Tuesday, March 31, 2009

Greenhouse - Sumagic Gets Label for Some Vegetable Transplants.

The following is some information on new labelled uses for Sumagic plant growth regulator on vegetable transplants.

The Plant Growth Regulator Sumagic from Valent Professional Products is now labeled for use on several vegetable transplants grown in commercial greenhouses. Sumagic, which contains the active ingredient uniconazole, is the first and only plant growth retardant that can legally be used on fruiting vegetable crops. This is a significant milestone, as growers have had to use a variety of environmental techniques and low levels of fertility to help maintain compact vegetable plugs.

Sumagic is specifically registered for use as a foliar spray on tomato, pepper, eggplant, groundcherry, pepino and tomatillo. The recommended label rate is 2 to 10 ppm at a volume of 2 quarts per 100 sq ft of crop. Experiments performed with Sumagic at Michigan State University in cooperation with Valent Professional Products, showed that as little as a single 1.0 ppm spray application had a noticeable effect on inhibiting extension growth of tomato seedlings. Therefore, as with all plant growth regulators, small-scale trials by growers are encouraged to determine appropriate rates for your growing conditions, crops grown and desired responses.According to the supplemental label, the total amount of Sumagic applied to vegetable transplants may not exceed that from a single 10-ppm spray application at 2 quarts per 100 sq ft. In addition, the final application may not occur later than 14 days after the 2 to 4 true leaf stage. Sumagic is registered for use on vegetable transplants in all states except California and New York. Finally, the supplemental label must be in the possession of the user at the time of application.

Reprinted from the current issue of the Michigan State Greenhouse Alert newsletter.

Nursery and Greenhouse - Caution When Using Glyphosate Around Nurseries and Greenhouses

The following is some information on cautions with using glyphosate around nurseries and greenhouses.

We have had cases of severe crop injury where glyphosate has been sprayed and has contacted pots or growing media in or around nurseries and greenhouses. Do not spray weeds in a media pile with glyphosate since it is absorbed on the organic material and can be taken up by the root system of plants grown in that media later on. The same goes for stacks of pots or containers. Glyphosate can be absorbed onto the organic matter adhering to pots or to the plastic itself and this residue can affect plants grown in those pots in the future. If you need to treat media piles or areas around pots for weeds, use Scythe instead since it has no residual impact.

Gordon Johnson, Extension Horticulture Agent, UD, Kent County

Monday, March 30, 2009

Landscape and Nursery - Plants for Delaware Landscapes Featured at the 2009 UDBG Spring Plant Sale #15

This year, the University of Delaware Botanic Garden spring benefit plant sale features those plants that add to the biodiversity of the landscape and offer food and habitat for wildlife, especially insects and the birds that eat them. Many native plants are featured. This is the 15th in a series on plants being offered at the UDBG spring plant sale that are recommended for Delaware landscapes.


Photo by Paul Wray, Iowa State University, Bugwood.org


Photo from The Dow Gardens Archive, Dow Gardens, Bugwood.org


Photo by Chris Evans, River to River CWMA, Bugwood.org



For more information on the 2009 UDBG Spring Plant Sale go to http://ag.udel.edu/udbg/events/annualsale.html

Sunday, March 29, 2009

Ornamentals Hotline - Issue 1, March 27, 2009

INSECTS
Brian Kunkel
Ornamental IPM Specialist

EUROPEAN PINE SHOOT MOTH larvae are active between 0 1889 [223 peak] GDD . This moth, Rhyacionia buoliana, prefers to feed 50 on Austrian, Eastern white, mugo and Scotch pines. Young trees between 6 8 m in height are very susceptible.

Overwintering larvae emerge and resume feeding on new shoots or expanding buds after about 20 200 GDD have accumulated 50 and this causes the greatest damage. Larvae are yellowish brown to brown with black head capsules and are about 13 mm when mature. Trees with feeding damage may have dead or stunted shoots appearing as if infected with Sphaeropsis (Diplodia) shoot blight. Shoots damaged but not killed continue to grow in an “S” shape called a posthorn. Spring feeding causes trees to produce numerous adventitious buds resulting in a witches-broom effect. The larvae pupate around mid-May and after about three weeks the orange-red adults emerge and lay eggs on needles, needle sheaths, or buds of new growth. First instars construct silken webs on needles of the current year's growth before they bore into needles to feed. Older larvae hollow out newly formed buds to overwinter.

NANTUCKET PINE TIP MOTH adults are active 100 1001 GDD , 50 when Syringa vulgaris is in bloom or Cornus mas is in full bloom. This moth, Rhyacionia frustrana, is a close relative of the previous moth and attacks most two- and three-needle pines shorter than 15 feet tall found in open locations. The adults are about ½ inch long. The forewings have reddish brown patches with silver-gray bands. Eggs laid by adults take between five and ten days to hatch unless cold weather follows oviposition, then it may take 30 days. The damage is often observed as delicate webbing found in the axil formed between the developing needle and stem. Shoots of infested terminals turn brown and are easily observed from a distance.

Predatory insects, parasitoids, and birds all attack the larvae of these moths. Chemical control includes: azadirachtin (Azatin), spinosad (Conserve), tebufenozide (Mimic), diflubenzuron (Dimilin), acephate, cyfluthrin (Tempo), or dimethoate.

DISEASES
Bob Mulrooney
Extension Plant Pathologist

WINTER DAMAGE. Temperatures have not fluctuated as drastically as in past years but we had cold temperatures this winter and there is some obvious winter damage on Japanese holly, yew and boxwood. These plants have dead branch tips scattered on the sun exposed sides. There has been minimal marginal leaf browning on broadleaved evergreens, but Mahonia species in the UDBG seem to have the most damage. Pruning out the dead branches and picking off the worst leaves is suggested now. It may be too early to assess other possible winter damage until new growth begins.

ROSES. Now is a good time to get out and prune roses to remove winter damaged and diseased canes. Cane cankers caused by black spot and powdery mildewinfected canes should be removed to reduce the incidence of these two important rose diseases, especially on hybrid tea roses. This is a good time to apply limesulfur to burn out any infections left after pruning.

KABATINA BLIGHT is present on susceptible upright and prostrate junipers. Look for scattered dead branch tips on infected plants. Often there will be a gray canker on the twig separating the dead tip from the healthy part of the branch. Infection takes place during the late summer and fall especially on stressed plants and the symptoms appear in the spring on the old growth. (As a reminder, Phomopsis tip blight it a different disease and only infects new growth.) Removing the dead tips is probably the best control. The infected tips will be shed anyway. Rake up infected tips as they fall to the ground and dispose of them to reduce the fungal spores at the site and limit future infection.

WEEDS
Gordon Johnson
Agricultural Agent, Kent County

CRABGRASS GERMINATION is closely correlated to soil temperatures and also to degree day accumulations based on maximum and minimum air temperatures. In work done in the 1990's at the University of Maryland, they found the following: The minimum soil temperature for initial crabgrass appearance is 54 F. The minimum soil temperature for major emergence of crabgrass is between 60-70 F. Soil temperature measured at the 1 inch depth should be used. Measuring soil temperatures first thing every morning is the best way to get this number. A rule of thumb is that crabgrass will start germinating with 3 consecutive night soil temperatures above 50 F. Preemergence herbicides should be applied prior to this time (when you observe the first nighttime soil temperature above 50 F germination will soon follow). Degree days can also be used. Degree days for crabgrass germination using a base of 53.6 follows: initial emergence 76-140 DD, 25% emergence 558 DD, 50% emergence 801 DD. As of March 23 in Dover we have accumulated 20.6 degree days based on 53.6 F. You can do your own degree day calculations using weather information from the DEOS system available at http://www.deos.udel.edu/.

Saturday, March 28, 2009

Landscape and Nursery - Plants for Delaware Landscapes Featured at the 2009 UDBG Spring Plant Sale #14

This year, the University of Delaware Botanic Garden spring benefit plant sale features those plants that add to the biodiversity of the landscape and offer food and habitat for wildlife, especially insects and the birds that eat them. Many native plants are featured. This is the 14th in a series on plants being offered at the UDBG spring plant sale that are recommended for Delaware landscapes.


Leucothoe fontanesiana ‘Nana’, Drooping Leucothoe, 3', full sun to full shade, moist soil conditions. The common name is quite appropriate as the arching branches droop effectively, particularly over a wall. The evergreen foliage becomes tinged red in the winter and displays the spring flowers well. Plants are best used in groups. Native plant. Photo from the Dow Gardens Archive, Dow Gardens, Bugwood.org.


Lindera benzoin, Spicebush, 6-12', full sun to full shade, moist soil conditions. Anyone who has walked our local woodlands has seen this shrub. The small chartreuse flowers appear in March before the foliage. Bright red fruit is produced on female plants in the fall. Leaves turn a clear yellow in the autumn. Native plant. Photo from the Dow Gardens Archive, Dow Gardens, Bugwood.org


Lindera melissifolia, Southern Spicebush, 3-6', full sun to part shade, moist soil conditions. Very similar to the spicebush in our local woodlands, it differs primarily in its shorter, slightly more suckering habit. It produces the same bright yellow flowers in March and bright red fruit in the early fall. Plants are dioecious. Native plant. Photo by Charles T. Bryson, USDA Agricultural Research Service, Bugwood.org

For more information on the 2009 UDBG Spring Plant Sale go to http://ag.udel.edu/udbg/events/annualsale.html

Turf and Landscape - Know Your Soluble Fertilizers 3

This is the third in a series on soluble fertilizers for use in turf and landscapes. This post is on ammonium nitrate, a nitrogen fertilizer.

Ammonium Nitrate is typically marketed in prilled form containing 33-34% N. It is highly soluble and is also marketed in solution form; generally it will be offered in combination with urea containing 28, 30 or 32% N. Prilled ammonium nitrate may be bright white in color, indicating that the prill has been coated with magnesium chloride, or beige in color, indicating that the product has been coated with a mixture of clays. Both of these coatings reduce the hygroscopicity of the product and improve handling properties. Ammonium nitrate and urea cannot be mixed together in dry form because of severely reduced handling properties. Ammonium nitrate produces only 1.8 pounds of acidity per pound of N applied upon nitrification, and thus is not as acidifying as ammonium sulfate. The salt index of ammonium nitrate, 2.99, is less than that of ammonium sulfate and thus there is less potential for turfgrass burn immediately after application. Ammonium nitrate generally does not impart as dark green a color as does ammonium sulfate and the longevity of the response is not as great.

Reprinted from "Selected Fertilizers Used in Turfgrass Fertilization" by J.B. Sartain & J.K. Kruse, University of Florida Cooperative Extension.

Friday, March 27, 2009

Landscape and Nursery - Systemic Insecticide Products

The following is information on systemic insecticide products for use in the landscape.

Imidacloprid: Bayer Company has released a slow release imidacloprid tablet that is inserted into the root zone of a tree and is being marketed under the trade name CoreTect. In trials in which hemlocks were treated for control of hemlock wooly adelgid a one-time treatment with the slow release formulation gave some control in the first year, improved control in the second year and 100 % control in the 3rd and 4th years after treatment. This material appears to have potential for longer term control of hemlock wooly adelgid.

Dinotefuran (Safari) : This neonicotinoid is 80 times more water soluble than imidacloprid and uptake is very rapid. It appears that dinotefuran works well for rescue treatments because of its rapid uptake by the plant. In applications made for control of whitefly it is giving knockdown within hours. It appears that it should be applied when plants are actively growing and transpiring. If you are trying to control aphids with dinotefuran it would be best to make a soil application. Foliar applications appear to be less consistent in control of aphids.

Reprinted from the March 20, 2009 edition of the TPM/IPM Weekly Report for Arborists, Landscape Managers & Nursery Managers, University of Maryland Cooperative Extension

Turf and Landscape - Know Your Soluble Fertilizers 2

This is the second in a series on soluble fertilizers for use in turf and landscapes. This post is on urea, a nitrogen fertilizer.

Urea is a white crystalline solid, generally marketed in prill form, containing 45-46% N. It has good physical properties and is not as hygroscopic as ammonium nitrate. It produces 1.8 pounds of acidity per pound of N and has a salt index of 1.62; thus it can be applied to turfgrass with little threat of burn when applied at recommended rates. If left on the soil surface, significant quantities of N may be lost by volatilization. Therefore, urea should always be watered in with the proper amount of water. Urea is a non-ionic compound when placed into solution and will leach rapidly through the soil profile if excess water is applied. Remember that one inch of water will effectively wet the top ten inches of a Florida sand soil profile. Urea is highly soluble and one of the materials of choice in N solution fertilizers. Generally speaking urea does not produce as good a turfgrass response as does ammonium sulfate or ammonium nitrate, but because of its ease of application in solution form, its high solubility, its low burn potential and low cost per pound of N, it is a popular soluble N source, particularly by lawn care maintenance personnel.

Reprinted from "Selected Fertilizers Used in Turfgrass Fertilization" by J.B. Sartain & J.K. Kruse, University of Florida Cooperative Extension.

Thursday, March 26, 2009

Turf and Landscape - Know Your Soluble Fertilizers 1

This is the first in a series on soluble fertilizer sources for use in turf or landscapes.

Ammonium Sulfate is a white crystalline material containing 20-21% N and 24% S. If produced in the pure crystalline form it is seldom marketed. The marketed product may be grayish in color due to carbon contamination during manufacture. Nitrification of ammonium sulfate produces acidity in the soil. Upon conversion to nitrate, the ammonium ion produces 5.35 pounds of acidity per pound of N applied, thus making ammonium sulfate the most acidifying N source available. This acidifying property makes ammonium sulfate the desired N source on alkaline turfgrass soils. When applied on high pH soils, particularly those containing free calcium carbonate, ammonium sulfate should always be watered in to limit volatile loss of N. Ammonium sulfate has a high burn potential with a salt index of 3.25, therefore, it should not be applied at high rates to avoid potential turfgrass burn. Due to limited solubility ammonium sulfate is not often applied in solution form. Ammonium sulfate imparts a dark green color in turfgrasses which tends to last for at least 30 days when applied at recommended rates. Turfgrass responses to ammonium sulfate tend to last for a longer period than for the other soluble N sources, and for this reason ammonium sulfate tends to be the preferred soluble N source of many turfgrass managers.

Reprinted from "Selected Fertilizers Used in Turfgrass Fertilization" by J.B. Sartain & J.K. Kruse, University of Florida Cooperative Extension.

Greenhouse - Common Issues with New Guinea Impatiens

New Guinea impatiens have been good sellers for greenhouse producers. However, they are somewhat difficult to grow well. The following are two common problems.

Lack of Blooming:

If New Guinea impatiens will not bloom then the problem is often that they are too crowded. When crowded the lower leaves are covered and do not photosynthesize well and reduces blooms. As the plants fill in, make sure they are adequately spaced.

Cupping of Leaves:

The cupping and wavy leaves appear to be favored by dry soil and cool moist air. These symptoms commonly show up in March and April and usually disappear as weather improves later in spring. A lot of the orange cultivars show this symptom in the early spring.

Information from the University of Maryland Greenhouse TPM/IPM Bi-Weekly Report.

Wednesday, March 25, 2009

Turf - Moss Control in Turf

The following are guidelines for moss control in Turf from Virginia Tech.

Moss gradually invades lawns in areas where the turfgrasses are growing poorly. The infested site may be described as wet, shady, highly acidic, and under low fertility. Aprogram to control moss involves correcting the turfgrass growing conditions as much as possible. Remove as much moss as possible by raking, vertical mowing and aerifying to prepare a seed bed to reseed thin turfgrass areas. Select a species/cultivar adapted to the area conditions. Maintain optimum growing conditions for the turfgrass as fertility, pH, moisture (not excessive) and mowing height/frequency. The turfgrass density is very important to prevent further moss encrochment. Sometimes a shade tree may be removed to allow enough light for good turfgrass growth.

Chemical formulations for moss control usually contain iron, copper, or potassium salts of fatty acids as active ingrediants. Ferrous sulfates and chelated iron products applied as liquid sprays are generally rapid and effective on moss. Dry formulations of ferrous sulfate monohydrate are available such as Moss Control Granules for Lawns containing 5% iron (follow label directions). Carfentrazone (Quicksilver T&O) is an herbicide for broadleaf control that can be used in lawns or putting greens for moss control. Apply 6.7 ounces Quicksilver T&Oper acre or 0.15 ounce per 1,000 square feet twice at 3-week intervals. Moss discoloration is a sign of successful treatment and takes longer under cool conditions. Moss control is temporary and treatment may be required annually. Managers should improve conditions for turfgrass growth while minimizing the favorable environment for the moss. Read and follow label directions carefully.

Reprinted from the 2009 Virginia Pest Management Guide (PMG) - Horticultural and Forest Crops edition.

Turf - Tall Fescue Varieties Recommended

The following are the turf type tall fescue varieties recommended from the MD/VA Turfgrass Variety Recommendation Work Group.

Tall Fescue

Category I – Recommended Tall Fescue Varieties (90–100% on a weight basis)

2nd Millennium, Avenger, , Biltmore, Bingo, Bravo, Cochise III, Constitution, Coyote II, Crossfire II, Davinci, Daytona, Endeavor, Falcon IV, Fidelity, Forte, Good-En, Grande, Greenkeeper WAF, Guardian 21, Houndog 5, Inferno, Justice, Kalahari(3), Magellan, Masterpiece, Matador, Matador GT, Onyx, Padre, Picasso, Penn 1901, Quest(3), Raptor, Rebel Exeda, Regiment II, Rembrandt, Rendition(3), Southern Choice II, SR 8250, Tarheel, Tarheel II, Tempest, Titanium, Turbo(3), Ultimate, Watchdog, and Wolfpack.

Category II – Promising tall fescue varieties (may be 90–100% of the mixture on a weight basis)

Blackwatch, Escalade, Grande II, Guardian 21, Hunter, SR 8550, SR 8600, Taos, Tombstone

Tuesday, March 24, 2009

Landscape, Nursery, and Turf - Comparisons of Neonicotinoid Insecticides

Neonicotinoid insecticides have been important tools for controlling tough insects in ornamental plants such as aphids, whiteflies, mealybugs, and scales. The following are comparisons of the different products on the market. Click on table for a larger image in a new window.


Information from the March 20, 2009 edition of the TPM/IPM Weekly Report for Arborists, Landscape Managers & Nursery Managers from the University of Maryland Cooperative Extension

Greenhouse and Nursery - Slow Release Fertilizer: Osmocote

This is the seventh in a series on slow release fertilizers. This post contains information on Osmocote.


Osmocote.

Production of Osmocote involves the coating of a soluble fertilizer core with a thermoset copolymer of dicyclopentadiene and a glycerol ester (linseed oil) dissolved in an aliphatic hydrocarbon solvent. Nutrient release patterns vary with the amount of coating applied and the substrate used. Coating weights vary from 10 to 20%. Typically, commercial products are blends of different coating weights. Coating substrates include, but are not limited to, urea, potassium sulfate, and ammonium nitrate. Product longevities range from 5 to 16 months, depending on the temperature.

Osmocote products, like most polymer-coated products, release by diffusion through a semipermeable membrane. Water vapor penetrates the resin coating and dissolves the water-soluble fertilizer core. The dissolved nutrients then diffuse back through the coating to the environment. Since temperature influences the rate of diffusion, temperature plays a big role in the nutrient release. The Osmocote market has been mainly limited to commercial ornamental horticulture production, such as nurseries and greenhouses.

Reprinted from Selected Fertilizers Used in Turfgrass Fertilization by J. B. Sartain and J. K. Kruse, University of Florida Extension.

Monday, March 23, 2009

Greenhouse - Annual Vinca Production

The following is some information on successful annual vinca production in the greenhouse.


Flowering annual vinca is a tough plant that needs a high soil temperature. They grow best at nighttime temperatures between 68 and 72 °F. Keep pH levels between 5.3 and 5.8 for optimum uptake of iron and suppression of Thielaviopsis. Pythium and Botrytis stem cankers are very common on vinca.

Vinca require warm greenhouse conditions to grow well. Heating the greenhouse to 70 degrees F at night is expensive, but if you wish to grow quality vinca, it is necessary. Bottom heat will greatly improve this crop's seedling growth and accelerate transplant flower production. Installation of in-bench soil warming systems will be a wise investment in greenhouses if you grow large amounts for Mother's day. However, a more economic solution is to grow this crop much later in the season. Warmer outdoor temperatures and increased sunlight make production a bit easier. In Delaware, ordering larger plugs of this crop for transplanting into containers in late March through April and growing them out during warmer weather with longer day lengths is a very sound decision.

With vinca, the larger plug sizes have an advantage in that the increased amount of root system greatly improves survival and regrowth after transplant. The development of a strong root system after transplant is essential for success. Most growers purchase 512s or 288s for spring bedding production. However, growing small vinca plugs under cool condition limits how fast a root system will develop. Put a small 512 plug in a 4-inch pot where the soil is likely to stay wet due to the small root system, and you will increase the chances for disease and root damage due to over-watering. Purchasing larger plugs, such as 144s, provides more root development in relation to the pot it is planted in and reduces the time it takes for roots to grow throughout the new media. Larger plug sizes perform better, grow quicker and are essential for early spring crops.

Information from the March 20, 2009 edition of the Greenhouse TPM/IPM Bi-Weekly Report from the University of Maryland Cooperative Extension Central Maryland Research and Education Center and from "A Guide for Commercial Production of Vinca" by Paul Thomas, Jean Woodward, Forrest Stegelin and Bodie Pennisi, The University of Georgia

Turf and Landscape - Slow Release Fertilizers: IBDU

This is the sixth in a series on slow release fertilizers for turf and landscapes. This post contains information on IBDU.

Isobutylidene Diurea (IBDU). Unlike the condensation of urea and formaldehyde, which forms a distribution of different UF polymer chain lengths, the reaction of urea with isobutyraldehyde forms a single oligomer. Although similar in chemical structure to methylene diurea (MDU), its physical properties are quite different.

Isobutylidene diurea (IBDU) is a non-hygroscopic white crystalline solid available in fine (0.5-1.0mm), coarse (.7-2.5mm) and chunk (2.0-3.0mm) particle sizes. The product contains a minimum of 30% N with 90% of the N in water-insoluble form. The typical commercialized product contains 31% N.

Nitrogen from IBDU becomes available to plants through hydrolysis. In the presence of water, the compound will hydrolyze to urea and isobutyraldehyde. The rate of hydrolysis is accelerated by low pH and high temperature. Unlike UF polymers that rely on soil microbialpopulations to make the N available, IBDU is primarily dependent on water as the critical element in N availability. Its low water solubility controls the transport of the product into the soil solution. Once in the soil solution, the rate of hydrolysis is affected by both soil pH and temperature. The rate of dissolution is affected by particle size and amount of water available. The powder form is mineralized much more rapidly than large particles under the same field conditions. Because the release is not microbe-dependent, N can become available at low temperatures; thus IBDU is one of the preferred products for cool-season application. This attribute and the dependency on moisture are the distinguishing characteristics of IBDU.

IBDU is used on turfgrasses, in commercial nurseries, and in landscaping, forestry, and speciality agriculture. Although some fine-size IBDU (31-0-0) is used for direct application to golf course greens, most of the turfgrass use is in the form of blended fertilizers, often in combination with other types of controlled release fertilizers.

Reprinted from Selected Fertilizers Used in Turfgrass Fertilization by J. B. Sartain and J. K. Kruse, University of Florida Extension.

Sunday, March 22, 2009

Greenhouse - Common Greenhouse Crops that Develop Iron Deficiency

The following is information on common greenhouse crops that develop iron deficiency if the pH is too high.

High pH and iron deficiency in Calibrachoas, Bacopa, Diascia, Scaevola, Verbena, and Petunia

For this group of plants (Calibrachoas, Bacopa, Diascia, Scaevola, Verbena, and Petunia) make sure to keep the pH between 5.3 and 5.8 to avoid problems with iron deficiency. We often see plants with interveinal chlorosis show up in the growing season. One of the approaches is to use an acidifying fertilizer such as 21-7-7 or 18-9-18. If you have high alkalinity water sources then the first choice should be sulfuric acid injection to lower the pH level. Keeping the pH low is the best way to prevent iron chlorosis but sometimes additional iron may be needed – apply as iron chelate or iron sulfate (always rinse foliage when using iron sulfate to prevent foliar burn). The pH can be lowered using iron sulfate at 1 - 3 lbs per 100 gallons. Apply chelated iron such as Sprint 138 or 330 as a drench at 3-5 oz per 100 gallons.

Reprinted from the March 20, 2009 edition of the Greenhouse TPM/IPM Bi-Weekly Report from the University of Maryland Cooperative Extension Central Maryland Research and Education Center.

Turf and Landscape - Slow Release Fertilizers: Ureaformaldehyde Reaction Products

This is the fifth in a series on slow release fertilizers for turf and landscapes. This post contains information on ureaformaldehyde reaction products.

Ureaformaldehyde Reaction Products, also known as Nitroform, Ureaform, UF, Methylene Urea, Blue Chip, Nutralene or Methex, represent one of the oldest controlled-release nitrogen technologies, having been first produced in 1936 and commercialized in 1955.

Ureaform is the oldest class of UF reaction products. Ureaform is sparingly soluble. It contains at least 35% total nitrogen with at least 60% of the total nitrogen as cold water-insoluble nitrogen (CWIN). Further, it must have an Activity Index (AI), i.e., the percent of CWIN that is soluble in hot (100°C) water, of not less than 40%. Ureaform is composed largely of longer-chained UF polymers, primarily tetramethylene pentaurea (TMPU) and longer. Unreacted urea nitrogen content is usually less than 15% of the total nitrogen. This product is commonly marketed under the following names: Nitroform, UF, Blue Chip, Powder Blue or Methex.

Methylene Ureas are a class of sparingly soluble products which evolved during the 1960s and 1970s. These products contain predominantly intermediate chain-length polymers, primarily trimethylene tetraurea (TMTU) and tetramethylene pentaurea (TMPU). The total nitrogen content of these polymers is 39 to 40%, with between 25 and 60% of the nitrogen present as CWIN. The unreacted urea content generally is in the range of 15 to 30% of the total nitrogen. This product is typically marketed under the trade name Nutralene.

UF solutions are clear water solutions. They contain only very low molecular-weight, water soluble UF reaction products plus unreacted urea. Various combinations of the UF solutions are produced. They contain a maximum of 55% unreacted urea with the remainder as one or more of methylolureas, methylolurea ethers, MDU, DMTU, or triazone. One of the commercial names under which this product is currently marketed as CoRon.

Agronomic Properties and Nutrient Release Mechanism of UF Products:

The conversion of UF reaction products to plant available N is a multistep process, involving dissolution and microbial decompositon. Once in the soil solution, UF reaction products are converted to plant available N through either microbial decomposition or hydrolysis. Microbial decomposition is the primary mechanism of N release with the carbon in the methylene urea polymers providing the site for microbial activity. Environmental factors such as soil temperature, moisture, pH and aeration affect the rate of N release.

The rate of N release from UF reaction products is directly affected by polymer chain length. The longer the methylene urea polymer, the longer it takes for the N to become available. For ureaform and methylene urea products, the rate of mineralization is reflected by the cold water insoluble N (CWIN) content and its Activity Index. It is questionable if the very long methylene urea polymers are effectively used by the plant.

Reprinted from Selected Fertilizers Used in Turfgrass Fertilization by J. B. Sartain and J. K. Kruse, University of Florida Extension.

Saturday, March 21, 2009

Greenhouse and Nursery - New Pesticides for 2009

The following is information on new pesticides available in 2009 for greenhouse and nursery use.

Kontos:

Bayer Company has introduced a new insecticide, Spirotetranat, sold under the brand name Kontos and distributed by OHP Company. This insecticide is a true systemic and is very similar to Judo which was released 3 or 4 years ago. Kontos has a label for greenhouses use, including application to vegetable transplants, nurseries and interiorscapes. Kontos can control most species of aphids. This might be a good material to try this spring for aphid control on pansy crops. It is also very effective in controlling whiteflies. Kontos contains an active ingredient with a mode of action classified as a Group 23 insecticide – lipid biosynthesis inhibitor (LBI). In studies to determine cross-resistance there have been no resistance detected.

Apply as a foliar or drench Application

Kontos can be applied as a foliar spray or applied as a soil drench. If you apply it as a foliar spray expect about 14 days of control. When applied as a soil drench the material is very water insoluble and will take 3 – 5 days to be uptaken by the plant. Once in the plant it will provide 30 - 40 days of aphid control. The rate is 1.7 oz in 100 gallons of water for use on herbaceous species and 1.7 – 3.4 oz/100 gallons of water for woody plants. Kontos works fairly well in controlling twospotted spider mites, but it is best applied when a population is small. It is presently being tested for efficacy in controlling thrips, fungus gnats and leafminers.

A different REI for greenhouse and nursery applications

If you apply as a foliar spray the material is listed as an eye irritant so there is a 24 hour REI. Applied as a soil drench the labels states “workers are allowed to enter the treated area if there will be no contact with anything that has been treated”.

Sucrashield:

Sucrashield is a new product that is based on a tobacco plant extract and is being marketed by Natural Forces. The active ingredients, sucrose octanoate esters, have an LD50 of 750 to1500 ppm. This product is classified by EPA as non-toxic to people and is in the same category as soaps and oil insecticides. Sucrashield bears a WARNING on the label because of eye sensitivity. There is no information on the label about phytotoxicity, so caution is recommended until you have tested it yourself or until phytotoxicity test data is available. Sucrashield is labeled for controlling aphids, mites, thrips, whiteflies and caterpillars on vegetables, and herbs in greenhouses and outdoors. This gives vegetable and herb growers one more option for insect control. It is labeled for use on ornamentals, flowers and bedding plants. Applications need to be repeated at 7 – 10 day intervals. This material is applied at a label rate of 104 oz (a little shy of a gallon) to 100 gallons of water for pests such as whitefly.

Reprinted from the March 6, 2009 edition of the Greenhouse TPM/IPM Bi-Weekly Report from the University of Maryland Cooperative Extension, Central Maryland Research and Education Center http://www.ipmnet.umd.edu/09Mar06G.pdf

Turf and Landscape - Slow Release Fertilizers: Thermoplastic Resin Coated Fertilizer

This is the fourth in a series on slow release fertilizers for turf and landscapes. This post contains information on another coated slow release fertilizer product using thermoplastic resins.

Meister products are produced by using thermoplastic resins, such as polyolefins, polyvinylidene chloride, and copolymers as coating materials. The coatings are dissolved in fast-drying chlorinated hydrocarbon solvents and are applied to a variety of substrates including urea, diammonium phosphate, potassium sulfate, potassium chloride, and ammonium nitrate. Because the thermoplastic polymers used are highly impermeable in water, release controlling agents such as ethylene-vinyl acetate and surfactants are added to the coating to obtain the desired diffusion characteristics. Coating thicknesses are essentially the same for all products with the release pattern being controlled by the level of release-controlling agent. Release rates can also be altered by blending talc resin into the coating.

As with other polymer-coated fertilizers, nutrients are released by diffusion through the coating. The various releasing agents incorporated into the coating change the permeability characteristics, while the amount of release agent contained in the coating determines how fast the nutrients will diffuse. As with most polymer-coated fertilizers, the release is largely controlled by temperature.

Reprinted from Selected Fertilizers Used in Turfgrass Fertilization by J. B. Sartain and J. K. Kruse, University of Florida Extension.

Friday, March 20, 2009

Turf and Landscape - Winter Annual Lamium Species as Weeds

There are a two winter annual Lamium species that are weeds of turf and landscapes. Other perennial Lamium species are used as ornamentals. The following are pictures of weedy species of this Genus.

Henbit, Lamium amplexicaule. Photo by Richard Old, XID Services, Inc., Bugwood.org

Purple or Red Deadnettle, Lamium purpureum. Photo by Richard Old, XID Services, Inc., Bugwood.org

Turf and Landscape - Slow Release Fertilizers: Sulfur-Coated Fertilizers

This is the third in a series on slow release fertilizers for turf and landscapes. This post contains information on sulfur coated fertilizers.

Sulfur-Coated Fertilizers.

Sulfur-coated urea (SCU) technology was developed in the 1960s and 1970s by the Tennessee Valley Authority. Sulfur was chosen as the principal coating material because of its low cost and its value as a secondary nutrient.

Sulfur-coated ureas (SCUs) are typically brown to tan to yellow depending on the source of urea, whether or not a sealant is used, and the type sealant employed. Soft sealants are typically used as a secondary coating over the sulfur coating to fill in imperfections in the sulfur coating and to provide handling integrity to the brittle sulfur coat. The total N content of SCUs varies with the amount of coating applied. SCUs available in the early 1990s ranged from 30 to 40% N.

Agronomic Properties and Nutrient Release Mechanisms of SCU :

The mechanism of N release from SCU is by water penetration through micropores and imperfections, i.e., cracks or incomplete sulfur coverage, in the coating. This is followed by a rapid release of the dissolved urea from the core of the particle. When wax sealants are used, a dual release mechanism is created. Microbes in the soil environment must attack the sealant to reveal the imperfections in the sulfur coating. Because microbial populations vary with temperature, the release properties of the wax-sealed SCUs are also temperature dependent.

The release rate of a SCU particle is directly affected by the coating thickness and the coating quality. Particles with higher sulfur loads, i.e., thick sulfur coatings, typically show fewer imperfections than particles with lighter coatings. There is a risk, however, that particles with too-thick sulfur coatings will exhibit lock-off, i.e., they may never effectively release their N.

Depending on the coating weight, N application rate, and environmental conditions, SCUs can have residual characteristics which provide agronomic response from 6 to 16 weeks in turfgrass applications. Because of the differential release of N due to the lack of uniformity in coating thickness and the influence of temperature on N release, severe mottling has been observed in turfgrass when SCU was applied during the cool-season growth period.

Reprinted from Selected Fertilizers Used in Turfgrass Fertilization by J. B. Sartain and J. K. Kruse, University of Florida Extension.

Thursday, March 19, 2009

Turf and Landscape - Slow Release Fertilizers: Polymer/Sulfur-Coated Fertilizers

This is the second in a series on slow release fertilizers for turf and landscapes. This post contains information on combination polymer/sulfur coated fertilizers.

Polymer/Sulfur-Coated Fertilizers. Polymer/sulfur coated fertilizers (PSCF) are hybrid products that utilize a primary coating of sulfur and a secondary polymer coat. These fertilizers were developed to deliver controlled- release performance approaching polymer-coated fertilizers, but at a much reduced cost. Sulfur is employed as theprimary coating because of its low cost. Low levels of a polymer surface-coat are used to control nutrient release rate. Unlike the soft wax sealants used to cover imperfections in the sulfur coatings of SCUs, the polymers in this case are chosen to provide a continuous membrane through which water and nutrients must diffuse. The water permeability characteristic of the polymer controls the rate of water diffusion into the particle. The combination of the two coatings permits a positive cost/benefit value over products with singular coatings of sulfur or polymer. They posses excellent abrasion resistance and handling integrity. Since the outer coating is a hard polymer, the products do not leave waxy residues on material handling and application equipment.

The nutrient release mechanism is a combination of diffusion and capillary actions. Water vapor must first diffuse through the continuous polymeric membrane layer. The rate of diffusion is controlled by the composition and thickness of the polymeric film. Once at the sulfur/polymer interface, the water subsequently penetrates the defects in the sulfur coat through capillary action and solublizes the fertilizer core. The solubilized fertilizer then exits the particle in reverse sequence. This diffusion-controlled mechanism permits greater uniformity in nutrient release as compared to the typical matrix release of sulfur-coated fertilizers. The agronomic advantages of this material are reduced surge growth after application and longer residual of up to six months. In addition, the combination coating renders the nutrient release much less temperature sensitive than most polymer-coated fertilizers.

Reprinted from Selected Fertilizers Used in Turfgrass Fertilization by J. B. Sartain and J. K. Kruse, University of Florida Extension.

Turf and Landscape - Winter Annual Speedwells

Winter annual speedwell species are common weeds of lawns and landscape beds. The following are three common annual speedwells found in Delaware.

Persian Speedwell. Photo from the Oregon State University Nursery Weed Identification Web Site.

Ivyleaf speedwell. Photo from the Oregon State University Nursery Weed Identification Web Site.

Corn Speedwell. Photo from Michigan State University Turf Weeds web site.

Wednesday, March 18, 2009

Greenhouse - Phytotoxicity in Greenhouses

The following is an article on pesticide phytotoxicity in greenhouses from the New England Greenhouse Update.

Pesticide phytotoxicity on plants can often be distinguished from pest problems by the pattern and timing of symptom development. Although the damage may take up to several days or more to occur, pesticide damage symptoms often occur all at once and have a regular distribution on the crop. Symptoms caused by pathogens usually develop over an extended period of time in random or grouped patterns. Pesticide phytotoxicity can be expressed by a number of different symptoms, including leaf speckling, cupping and twisting and other leaf distortions or plant death. Pesticides with hormone-type activity such as the insect growth regulator Distance and herbicides containing 2,4-D tend to produce leaf cupping and twisting. Other pesticides that have caused twisted growth include Judo applied to dracaena plugs and Botanigard ES applied to tomato plants.

Phytotoxicity can also be caused by the solvents in a formulation (EC formulation vs WP), impurities in spray water, using a higher rate of pesticide than is listed on the label, tank-mixing or inadequately mixing the spray solution. Environmental conditions such the temperature, humidity, and light can also influence phytotoxicity. High temperatures can speed up pesticide degradation and volatilization, but may also result in increased phytotoxicity for some products. Plants that are stressed are more susceptible to pesticide injury.

Growers can prevent pesticide damage to plants by applying pesticides during the cooler part of the day such as the early morning or evening. Treatments made in the early morning allow foliage to dry before temperatures reach 85-90°F. Take special precautions when using oils. Treat when conditions allow plants to dry quickly. Other suggestions to prevent burning plants with pesticides include:

1) Add surfactants only when recommended on the pesticide label.
2) Never use a sprayer for insecticides that was previously used to apply herbicides.
3) Do not apply pesticides to plants that are under moisture stress.
4) Avoid using more than one emulsifiable concentrate in a tank mix.
5) Do not apply pesticides with fertilizers unless the label states otherwise.
6) Never use broad-leaved weed killers and brush killers around the greenhouse.

To prevent injury due to pesticides, be sure to follow label directions exactly. See the company’s website to read any technical bulletins about the product or call the company’s technical representative before using a product for the first time.

If minor phytotoxicity is suspected from foliar applications of an insecticide, miticide or fungicide, watch the new growth as it emerges. Plants will often grow out of one-time spray damage. As plants grow, the damage will remain on the oldest leaves and the new growth will appear healthy.

Reprinted from the current edition of the New England Greenhouse Update.

Tuesday, March 17, 2009

Greenhouse and Nursery - Managing Spider Mites

The following is a good article from the New England Greenhouse Update on managing spider mites in greenhouses. It would also apply to perennial nursery production under protection.

Watch for two-spotted spider mites on ipomoea, New Guinea impatiens and other crops. Mites may come in on incoming plants or have over-wintered in your greenhouse. Look for dull stippled foliage on plants particularly in warm, dry locations in your greenhouses such as near steam pipes, furnaces, heaters or overhead hangers. Use a 10x handlens and look on the underside of mature leaves, especially along the midvein for eggs, immature stages and adults. Note that young nymphs do not have the dark two spots.

Contact or translaminar miticides can be used to manage two-spotted mites. Translaminar means that the material penetrates leaf tissues and forms a reservoir of active ingredient within the leaf which provides extended residual activity. Miticides with translaminar activity include abamectin (Avid), etoxazole (TetraSan), chlorfenapyr (Pylon) and spiromesifen (Judo). After treatment, mark several plants and use a 10X hand lens to look for live and dead mites and eggs. Most miticides are not effective against the egg stage, so repeat applications may be needed in 5-7 days. Thorough coverage is important for contact activity. Insecticidal soaps and horticultural oils are also effective. Consult label for plant safety. Go back and check plants within a few days to see how effective the treatment worked. You will hopefully see dead and dying mites, but you may also see eggs. Continue to monitor and repeat treatments as needed.

Biological ControlA fast acting predatory mite that is commercially available is Phytoseiulus persimilis. This predatory mite only feeds upon spider mites, and will disperse or starve with no prey. The adult P. persimilis is bright red in color, pear shaped, long-legged and slightly larger and more active than spider mites.

P. persimilis is best released when mite populations are first noticed, in hot spots of mite activity and adjacent areas. Relative humidity should be greater than 75% and temperatures above 68F for some hours of the day. (At low relative humidity, less than 60%, eggs shrivel and do not hatch.). According to Raymond Cloyd, University of Kansas, P.persimilis is suitable for short-term crops such as bedding plants at release rates of 1-4 mites per ft² per week. Two applications, one week apart may be required. Spider mite colonies should be reduced in two to three weeks. To scout, shake plants over white paper and observe mites. Pest control materials that have been shown to be compatible with P. persimilus include spinosad (Conserve), pymetrozine (Endeavor) and clofentezine (Ovation). Bifenazate (Floramite), spromesifen (Judo) and chlorfenapyr (Pylon) may be harmful.

The spider mite predator Neoseilus californicus is slower acting than P. persimilis, but can survive longer in the absence of prey. It is useful for keeping low spider mite populations under control. In certain situations where high temperature or relative humidity variations can occur, N. californicus may be an option. N. californicus is active at temperatures between 46°F to 95°F, 40-80% relative humidity. At low pest densities, it declines less than P. persmilis, for N. californicus can survive on other mites, thrips, molds and nectar. N. californicus can also be introduced preventively and is compatible with P. persimilis. Some suppliers offer a mix of different species of predatory mites.

Reprinted from the New England Greenhouse Update http://www.negreenhouseupdate.info/greenhouse_update/index.php

Greenhouse and Nursery - Spider Mites and Predatory Mites for Their Control

The following are pictures of spider mites and predatory mites that are used for their control.

Two spotted spider mite. Photo by Whitney Cranshaw, Colorado State University, Bugwood.org.

Predatory mite, Phytoseiulus persimilis, a biological control for spider mite. Photo from "Biological Control of the Twospotted Spider Mite in Greenhouses" University of Florida, Central Florida Research and Education Center.

Neoseilus californicus, another predatory mite of spider mites. Photo from y Mark S. Hoddle, Department of Entomology, University of California, Riverside.

Monday, March 16, 2009

Landscape - Honeybee Swarm Removal

Honeybee swarms can cause home owners to become alarmed. Landscapers should be aware of these swarms and be prepared to help the homeowner by calling a bee keeper to remove the swarm. The following are some beekeepers in Delaware you can call to see if they will remove a swarm.


Click on lists for a larger version in a new window.





Nursery and Landscape - Insect Control Basics

The following are are some insect control basics for nurseries and landscapes.

There is no simple magic formula for pest control on trees and shrubs. More than 250 species of insects and mites are commonly found which damage or are potentially injurious to over 100 genera of woody ornamentals. Great diversity by insects in host preferences, seasonal development, periods of activity, habits, and susceptibility to insecticides requires careful planning and critical timing of control measures. It is a simple fact that insects and mites will occur, multiply, and cause serious losses if ignored or inadequately controlled.

The most frequent cause of insect problems is the failure of nurserymen and landscapers is to carry out necessary control procedures properly at the right time due to pressures from other phases of production and maintenance. The consequence, without exception, is a much more difficult and costly situation.

The best way to control insects and mites is a preventive program. First, do not introduce pest problems. In nursery production, propagate or buy ONLY clean, uninfested stock plants. In municipal tree plantings or private landscaping, set out ONLY insect-free plant materials. The presence of a few hardly noticeable insects or mites at planting time is a sure source of extra work and costly effort later on. Second, draw up a seasonal pest monitoring schedule to prevent the establishment and buildup of insects and mites. Third, maintain regular surveillance of established plant materials and be prepared to schedule control measures for difficult or complex pest problems which arise.

Take advantage of assistance from your local Extension agent and the Extension specialists at the University of Delaware. Sussex - Tracy Wooten (302) 856-7303; Kent - Gordon Johnson (302) 730-4000; New Castle - Carrie Murphy (302) 831-1426.

Information take from the Virginia Pest Management Guide, Nursery Insect section by Peter B. Schultz, Extension Entomologist, Hampton Roads AREC, and Eric R. Day, Extension Entomologist, Virginia Tech.

Sunday, March 15, 2009

Landscape and Nursery - Plants for Delaware Landscapes Featured at the 2009 UDBG Spring Plant Sale #13

This year, the University of Delaware Botanic Garden spring benefit plant sale features those plants that add to the biodiversity of the landscape and offer food and habitat for wildlife, especially insects and the birds that eat them. Many native plants are featured. This is the thirteenth in a series on plants being offered at the UDBG spring plant sale that are recommended for Delaware landscapes.

Ilex opaca ‘William Hawkins’, American Holly, 6-15', full sun to part shade, moist to wet soil conditions. If you did not know this is an American holly, you would never guess it by looking at it. The foliage is extremely narrow and results in slower than normal growth but produces stunning plants at maturity. After 15 years, the UDBG plant is 7 feet tall. Native plant.


Ilex verticillata ‘Red Sprite’, Winterberry Holly, 3-5', full sun to part shade, moist to wet soil conditions. The more compact habit of this cultivar, combined with the large red fruit, make this a great plant for foundation plantings, shrub borders and group plantings. Native plant. Photo from Natural Landscapes Nursery, West Grove, PA, http://www.naturallandscapesnursery.com/ilex_vert.html.


Ilex verticillata ‘Winter Red’, Winterberry Holly, 6-10', full sun to part shade, moist to wet soil conditions. One of the most widely planted cultivars due to it numerous, bright red fruit. The fruit is one of the showiest of all deciduous hollies. Native plant. Photo Copyright © 2009 by Nature By Design. All rights reserved website http://www.nature-by-design.com/plantlist2009.html


For more information on the 2009 UDBG Spring Plant Sale go to http://ag.udel.edu/udbg/events/annualsale.html

Saturday, March 14, 2009

Landscape and Nursery - Plants for Delaware Landscapes Featured at the 2009 UDBG Spring Plant Sale #12

This year, the University of Delaware Botanic Garden spring benefit plant sale features those plants that add to the biodiversity of the landscape and offer food and habitat for wildlife, especially insects and the birds that eat them. Many native plants are featured. This is the twelth in a series on plants being offered at the UDBG spring plant sale that are recommended for Delaware landscapes.


Hypericum kalmianum ‘Blue Velvet™, St. John’s-Wort, 2-3', full sun, dry to moist soil conditions. Striking blue foliage offers a perfect backdrop for the bright yellow flowers in summer, followed by red fruit. Great plant in masses or mixed with perennials. Pollinators love. Native plant.

Hypericum kalmianum ‘Deppe’ Sunny Boulevard™, St. John’s Wort, 2-3', full sun, dry to moist soil conditions. Numerous golden yellow flowers throughout the summer followed by red fruit combine to make for a long season of interest in the garden. Pollinators love this plant. Native plant.

Ilex glabra ‘Nova Scotia’, Inkberry holly, 2-4', full sun to part shade, moist to wet soil conditions. One of the best inkberries as it maintains a compact dense habit without pruning. It is a female and produces small black fruit, slightly hidden by the evergreen leaves. It is valuable for foundations, hedges, and massing. Native plant.


For more information on the 2009 UDBG Spring Plant Sale go to http://ag.udel.edu/udbg/events/annualsale.html

Friday, March 13, 2009

Thursday, March 12, 2009

Greenhouse and Nursery - Crown Gall on Perennials

The following is a good article on crown gall, a disease that attacks woody plants in the nursery, but can also perennial plants.

Agrobacterium tumefaciens is the bacterial pathogen that causes crown gall. Crown gall is well known as a disease of woody ornamentals and tree fruits, but it can also affect herbaceous perennials. Producers of perennials, especially those propagated by cuttings, should be aware of the disease and the symptoms it causes. The bacterium typically induces plants to produce an abnormally large number of cells that make up the gall. Galls range from pea-size to larger than one foot in diameter and are produced on roots, stems and foliage. Agrobacterium tumefaciens is soil borne and can survive in soil without a host for several years. The bacterium enters plants through wounds, often those made by cultural practices such as grafting, pruning or taking cuttings. Once inside the host plant it induces gall formation. Larger galls may destroy vascular tissue of the plant, causing dieback or plant death. With time gall tissue breaks down, releasing A. tumefaciens back into the soil or onto other host material.

Good sanitation is an important component of crown gall disease control. Equipment used to prune plants or to take cuttings should be thoroughly disinfested. Symptomatic plants should be removed and destroyed. Greenhouse plants that are in close proximity to those with galls should also be removed and destroyed; these may be infected although they are not yet showing symptoms. There are several disease control products available for crown gall control; these contain a strain of Agrobacterium that is antagonistic toward the gall causing pathogen. The efficacy of these products varies somewhat with the type of plant material being treated. These products are meant to protect healthy plant material; they do not eradicate current infections. Copper-based fungicides can be used to help limit spread, but again these will not eradicate current infections.

Crown gall on rose. Photo from the Online Guide to Plant Disease Control from Oregon State University Extension.

Article reprinted from "Managing crown gall" by Jan Byrne, Diagnostic Services, Michigan State University, from the current issue of the Michigan State University Greenhouse Alert newsletter.

Greenhouse and Nursery - Good Publication on Heating With Biomass Fuel

There is increasing interest in alternative fuels for heating greenhouses and nursery propagation areas. The following is a link to a great new publication on the topic of heating with biomass fuel from Michigan State University.

New MSU Extension publication: Heating buildings and business operations with biomass fuel

This new MSU Extension publication written by Dr. C.H. Schilling at Saginaw Valley State University and Mark Seamon, Thomas Dudek and Stephen Harsh from Michigan State University, is a detailed 24-page publication written by experts in the field of biomass fuels as alternative heat sources. The publication outlines the pros and cons of biomass heating systems, economics involved, and the environmental and regulatory issues related to the use of biomass burners in Michigan.To obtain a copy of this publication either download the pdf at: www.web2.msue.msu.edu/bulletins/Bulletin/PDF/E3044.pdf

Tuesday, March 10, 2009

Landscape - New Sustainable Landscapes Web Site at UD

Sustainable landscaping is being promoted throughout the country, yet there is considerable confusion on what sustainable landscaping means. The Univerisity of Delaware has produced a website to help explain the concept of sustainble landscaping in an easy to understand format. The following is more information:

A sustainable landscape Web site has been launched by the University of Delaware Botanic Gardens. The site's content was written in large part by Rebecca Pineo, who is serving her second year-long internship with the Botanic Gardens. A 24-year-old graduate of St. Mary's College of Maryland, she has applied to UD's Longwood Graduate Program in Public Horticulture for the 2009-2010 academic year. “The term 'sustainable landscape' gets thrown around a lot but there's not always agreement on what it means,” said Pineo. “This Web site defines it as a stable and productive ecosystem that conserves the physical and biological processes occurring on that landscape.” Most importantly, said Pineo, the Web site explains why sustainable landscaping is a good thing to do. Sustainable landscapes are promoted for maintaining soil integrity, hydrological function, plant and animal diversity, and contributing to human wellness.

The site is divided into five major categories - soils, hydrology, vegetation, human wellness and materials (which includes such topics as renewable landscape products and recycling leaves).
The soil section gives an overview of the basics, including how to do a soil test. But it also details the ins and outs of fertilizer usage, composting, soil compaction, and 10 full pages of info about integrated pest management.

“Rebecca did a great job of taking complex topics and material and presenting it in a reader-friendly format,” said Sue Barton, UD Cooperative Extension's specialist for ornamental horticulture, and Pineo's adviser on the project. “I think the sustainable landscape Web site will be a useful tool for Delaware gardeners who want to protect the natural environment.”

The website is at: http://www.ag.udel.edu/udbg/sl/

Nursery and Greenhouse - Phytophthora Root Rot

Phytophthora root rot and aerial blight can be a major source of losses in nurseries and greenhouses. The following is information on Phytophthora control from Michigan State University.

Phytophthora (Phytophthora nicotianae and Phytophthora drechsleri are examples) can be found in floriculture crops and can cause root, crown, and foliar blights. Losses can be especially severe in greenhouses and production fields where warm temperatures and ample water favor epidemics. Recirculating irrigation water can enhance the spread of Phytophthora.

Phytophthora is difficult to control because it produces several different spores that can cause disease. Thick-walled oospores survive between crops on plant containers, benches, floors, and in potting media or soil. Other spores include lemon-shaped sporangia, thick-walled chlamydospores, and swimming zoospores. Water is important for disease and under warm, wet conditions many spores develop on infected plants and lead to a rapid build-up of disease and spread in a short period of time.

Once an epidemic has developed in a production site it is often difficult to determine how the Phytophthora was introduced, how it is spreading, and if it is surviving from year to year. Using genetic tools, research conducted at MSU showed that Phytophthora spread within the greenhouse or nursery can occur from sporangia that can travel through the air or zoospores that spread through the water. Recent research also shows how Phytophthora may spread among producers. For instance, snapdragon producers at two locations purchased plugs from the same supplier. The Phytophthora from the two locations was identical. While it is possible that the disease was introduced to the locations via infected plants, it is also possible that the Phytophthora was already established at these production sites. The Phytophthora recovered from snapdragons was identical to the Phytophthora collected from the same facility in a previous year indicating the potential for this pathogen to survive even with a fallow period and treatment with a fumigant (methyl bromide/chloropicrin).

In another example, verbena propagated at one greenhouse via cuttings was sold to two other greenhouses for finishing. The finding that the Phytophthora from all three locations were genetically identical suggests that infected plants could have spread P. nicotianae from the propagator to the two growers.

Controlling the spread of Phytophthora spp. within and among production facilities can be difficult and there are two major challenges. First, Phytophthora must be kept out of the production site. This is particularly difficult with floriculture crops because of the widespread distribution of pre-finished plants. Also, plants may not exhibit obvious symptoms until the infection is well established or the plant becomes stressed (e.g., over- or under-watering). Infected plants treated with fungicides may appear healthy until the fungicides wear off and Phytophthora increases. The second challenge is eradicating Phytophthora once it has been introduced. Removing visibly diseased plants will not prevent spore production and spread from plants showing few if any symptoms. Sanitation can limit disease and includes removing plant debris, disinfecting pots, and production surfaces. Routinely treating plants with fungicides including mefenoxam (Subdue MAXX) can be helpful. However, Phytophthora can develop resistance to these fungicides and new management strategies and tools are needed.

Reprinted from "Phytophthora root rot update" by Mary Hausbeck and Blair Harlan, Plant Pathology, Michigan State University the current issue of the MSU Greenhouse Alert Newsletter http://www.ipm.msu.edu/grnhouse09/G02-02-09.htm#9.

Monday, March 9, 2009

Landscape and Nursery - Plants for Delaware Landscapes Featured at the 2009 UDBG Spring Plant Sale #11

This year, the University of Delaware Botanic Garden spring benefit plant sale features those plants that add to the biodiversity of the landscape and offer food and habitat for wildlife, especially insects and the birds that eat them. Many native plants are featured. This is the eleventh in a series on plants being offered at the UDBG spring plant sale that are recommended for Delaware landscapes.


Hydrangea arborescens ‘Hayes Starburst’, Smooth Hydrangea, 3-4', full sun to full shade, moist soil conditions. Sterile, double white flowers, with fertile flowers held beneath, add significant interest to the garden from June through August. Native plant.


Hydrangea quercifolia ‘Alice’, Oakleaf Hydrangea, 8-12', full sun to part shade, moist soil conditions. To sum it up in one word – robust! A vigorous plant producing flower clusters 1 foot or more in length with quarter sized flowers. The white flowers fade pink in the fall, looking great with the burgundy colored foliage. Native plant.


Hydrangea quercifolia ‘Sikes Dwarf’, Oakleaf Hydrangea, 3-4', full sun to part shade, moist soil conditions. Half the mature size of the straight species and perfect for planting under windows, where you can enjoy white flowers in summer and burgundy leaves in fall. Native plant. Photo from ecommons@cornell, http://hdl.handle.net/1813/1195.


For more information on the 2009 UDBG Spring Plant Sale go to http://ag.udel.edu/udbg/events/annualsale.html

Greenhouse - Fungicide Trials Michigan State

The following are results from some greenhouse fungicide trials at Michigan State University.

Click on graphs for a larger version in a new window.






Information from Mary Hausbeck and Blair Harlan, Plant Pathology, Michigan State University http://www.ipm.msu.edu/grnhouse09/G02-02-09.htm#11

Sunday, March 8, 2009

Landscape and Nursery - Plants for Delaware Landscapes Featured at the 2009 UDBG Spring Plant Sale #10

This year, the University of Delaware Botanic Garden spring benefit plant sale features those plants that add to the biodiversity of the landscape and offer food and habitat for wildlife, especially insects and the birds that eat them. Many native plants are featured. This is the tenth in a series on plants being offered at the UDBG spring plant sale that are recommended for Delaware landscapes.

Fothergilla × intermedia ‘Blue Shadow’, Hybrid Fothergilla, 6-10', sun to part shade, moist soil conditions. A new hybrid with powdery-blue leaves, most prevalent on new foliage. It also boasts bottlebrush white flowers in spring and brilliant orange red color in fall. Native plant.


Gelsemium sempervirens ‘Pride of Augusta’, Carolina Jessamine Vine, trellis, full sun to full shade, moist soil conditions. Evergreen vines are a welcome sight in the winter landscape and this one does not disappoint. The twining vine is appropriately vigorous and beckons spring with fully double golden flowers in March and April. Native plant.


Hamamelis vernalis, Vernal Witchhazel, 6-10', full sun to full shade, moist to wet soil conditions. This plant flowers well before the vernal equinox. Flowers are typically yellow, somewhat fragrant, and can start in February and last 4 weeks or more. Combined with good yellow fall color, this is a great plant for the shrub border and naturalizing. Native plant. Photo from The Dow Gardens Archive, Dow Gardens, Bugwood.org.


Hamamelis virginiana, Common Witchhazel, 20-30', full sun to full shade, moist to wet soil conditions. Relatively common in our native woodlands, this large shrub often grows along streams. It produces numerous 4-petaled yellow flowers in October and November. Native plant. Photo by Chris Evans, River to River CWMA, Bugwood.org.


For more information on the 2009 UDBG Spring Plant Sale go to http://ag.udel.edu/udbg/events/annualsale.html

Greenhouse - Downy Mildew and Its control

Downy mildew is a relatively new disease for greenhouse growers to contend with. The following is some information on this disease and its management.

Downy mildew is a water mold and related to the well-known Pythium and Phytophthora pests. Impatiens, rose, snapdragon, alyssum, pansy and salvia are susceptible to downy mildew and often suffer from the disease. Other crops such as cineraria, lisianthus, ranunculus, coleus and anemone may also become infected by a downy mildew pathogen although the disease problems are less frequent. Snapdragons, roses, impatiens and other crops susceptible to downy mildew each have a unique downy mildew pathogen. While the disease may look similar on the different crops, they are quite different. The downy mildew on snapdragons cannot blight roses, nor can the downy mildew on impatiens spread to coleus.

Downy mildew recommendations

Don’t forget to look under the leaves. Downy mildew may be restricted within the plant without causing severe injury. For instance, leaf spots are called “local infections” and are considered mild symptoms because the downy mildew is limited within the plant. However, if downy mildew advances and invades the internal or vascular part of the plant, the disease becomes “systemic” and is more destructive. When the infection is systemic, it affects the internal mechanism of the plant and hampers its ability to grow. Plants become stunted and yellowed with distorted leaves. When young plants and seedlings are infected, they generally do not survive. Downy mildew produces purplish, gray fuzz on the underside of the leaves. This can go unnoticed because growers are not accustomed to turning over the leaves to look for plant problems. Other than an especially severe case of Botrytis, no other disease causes gray or purplish fuzz on the underside of the leaf.

Look for the disease.

Downy mildew is often explosive and early detection is critical. The downy mildew pathogen produces plenty of spores called sporangia that are spread via air currents to nearby healthy plants. Turn the leaves over to look for gray or purplish fuzz. Susceptible crops should be scouted weekly. Don’t forget to check the susceptible crops when you receive them and continue to check them once they’re potted especially if they’re in baskets that are hard to monitor.
Keep the production area clean. If you had downy mildew last year, this pest may persist in soil and growing media and mats via a thick-walled spore. The downy mildew pest can also reside in compost or cull piles where volunteer plants are likely. Once these volunteer plants become infected, spore production ramps up and the disease is off and running.

Downy mildew likes water.

Limit this disease by venting, reducing the time that leaves are wet, and keeping relative humidity to a minimum. Water plants at a time of day that allows the foliage to dry quickly. Downy mildew is a water mold because it needs water to grow and develop. Any strategy that reduces water, leaf wetness, and relative humidity in a greenhouse will help limit downy mildew.
Apply effective fungicides preventively.

Fungicides should be used for plants prone to downy mildew when the weather is favorable for an outbreak but before disease develops. A protectant fungicide such as mancozeb acts as a barrier to the downy mildew pathogen but is not absorbed by the plant so the spray program must begin prior to a disease outbreak. At MSU, downy mildew studies with snapdragons and vegetable crops have shown that weekly sprays of mancozeb effectively limit downy mildew if applications are made early and repeated frequently. Mancozeb sprays can serve as a relatively low cost, effective foundation for downy mildew protection. Systemic fungicides can be added to the fungicide program as needed. Systemic fungicides can be especially helpful in managing downy mildew because these products are absorbed by the plant in a limited way and can fight the pathogen from the inside out. Systemic fungicides include mefenoxam (example: Subdue MAXX), which is labeled as a soil drench only. Mefenoxam 2 applied to the soil performed well in most of our downy mildew trials with snapdragon. Stature and Fenstop are also downy mildew fungicides. Cyazofamid is currently an unregistered product that provided exceptional control in two trials. Other products that appeared helpful but did not always perform as well as Stature include Compass, zoxamide + mancozeb (not registered), Echo, Aliette, and cymoxanil (not registered).

Downy mildew has a tendency to change and become resistant to the systemic fungicides (Subdue MAXX is an example.). Since Subdue MAXX is especially at risk, it should only be used once in a production program and must be applied as a drench only. Using mancozeb is not likely to cause the pathogen to change and become resistant so using multiple applications of this fungicide is considered OK. Fungicides such as the strobilurins (Compass is an example.) and Aliette should be used only in rotation with other fungicides that have a different mode of action to ensure that they remain effective and reliable tools.

Reprinted from "Downy mildew update" by Mary Hausbeck and Blair Harlan, Plant Pathology, in the February 2009 edition of the Greenhouse Alert newsletter from Michigan State University.

Saturday, March 7, 2009

Landscape and Nursery - Plants for Delaware Landscapes Featured at the 2009 UDBG Spring Plant Sale #9

This year, the University of Delaware Botanic Garden spring benefit plant sale features those plants that add to the biodiversity of the landscape and offer food and habitat for wildlife, especially insects and the birds that eat them. Many native plants are featured. This is the ninth in a series on plants being offered at the UDBG spring plant sale that are recommended for Delaware landscapes.


Cornus alternifolia, Pagoda Dogwood 15-25', sun to part shade, moist soil conditions. A much underrated native shrub with white flowers in April to May, blue-black fruit borne on red stems in late summer, and rich burgundy foliage in the fall. Very horizontal habit. Native plant. Photo from the Dow Gardens Archive, Dow Gardens, Bugwood.org.


Cornus racemosa,Grey Dogwood, 10-15', 2-3', sun to part shade, dry to wet soil conditions. The common name is derived from the winter stem color. Plants produce abundant white flowers in the spring and white fruit are borne on showy red stems in the late summer. Fruit is a delicacy, sought by more than 100 species of birds. Native plant. Photo by Richard Webb, Self-employed horticulurist, Bugwood.org.


Corylus americana, Filbert 4-6', full sun to full shade conditions, moist to wet soil conditions. A frequent component of our native woodlands, this shrub typically grows as an understory plant but becomes denser in habit, fruits more heavily, and exhibits intense fall color when grown in full sun. Wildlife love the nuts. Native plant. Photo by Richard Webb, Self-employed horticulurist, Bugwood.org.

For more information on the 2009 UDBG Spring Plant Sale go to http://ag.udel.edu/udbg/events/annualsale.html