Friday, September 5, 2008

Landscape - Tulip tree and Magnolia Scales

Tulip tree and Magnolia scales are often noticed in late summer because of the large amount of honeydew produced. The following is more information.

TULIP TREE & MAGNOLIA SCALE. Tulip tree scale feeds on tuliptree, magnolia, and occasionally lindens; whereas magnolia scale feeds on magnolias, tuliptree, and possibly Virginia creeper. Both species resume feeding in the spring and mature by late July. Feeding by either species results in copious amounts of honeydew and sooty mold may be found July through August. Female tulip tree scales are grayish green to pinkish orange mottled with black and their crawlers are active from 2016 to 3212 [2860 peak] GDD. Female magnolia scales are tan brown, smooth and are often covered with a white mealy wax until crawlers emerge. Magnolia scale crawlers are active from 2075 to 3247 [2746 peak] GDD. Crawlers may also be dispersed by wind or birds and once crawlers find a suitable place they settle to feed. There is only one generation per year and both overwinter as second instars. Ants and wasps found in trees may indicate an infestation because they frequently feed on the honeydew. A number of natural enemies feed on this scale including a predaceous caterpillar; however they are often insufficient to manage populations. Horticultural oil, insecticidal soap, or Distance is recommended for control during crawler activity. Imidacloprid or other neonicotinoids can be used for control, but must be applied earlier in the summer so there is sufficient time for the product to move to target areas of the plant. Other treatments applied during crawler activity include acephate or one of the pyrethroids.

Tuliptree scale. Photo by Gerald J. Lenhard,

Magnolia Scale. Photo by Brian Kunkel, UD Ornamental IPM Specialist.

Information from Brian Kunkel, Ornamental IPM Specialist, UD

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