Tuesday, November 20, 2007

Greenhouses - Judo, a New Chemical Option for Mite and Whitefly Control in Greenhouses

Judo is a new mite and whitefly control chemical for use in greenhouses. It is of a new and different chemical class and can help with resistance managment. It is very useful for Poinsettias. However, it does show phytotoxicity on some other greenhouse plants so check the label for plant sensitivities and test on a small number of plants before you use it in the whole greenhouse if you have not used it before. The following is an article from New York on using Judo.

Judo is labeled for spider mites, Tarsonemid mites (broad and cyclamen) and Tenuipalpid mites, and greenhouse, silverleaf and sweetpotato whiteflies (see label for specific species). It is reported to be active on all mite development stages, with juvenile stages more susceptible than adults, and to be most active against whitefly nymphs and pupae. Dan Gilrein has found Judo to be effective against the Q-biotype of silverleaf whitefly (Bemisia argentifolii), which is less susceptible to many of the insecticides currently used to manage the A and B biotypes of silverleaf whitefly in the greenhouse, and has the potential to become an increasing pest in New York State greenhouses.

Judo is reported by the manufacturer to be soft on beneficial insects used for biological control. Based on the Koppert Biological Systems website on side effects (check for Side Effects in the left sidebar), it would be appropriate for use with some of the common biological control agents for whitefly or spider mites. Spiromesefin is listed as harmless to Encarsia formosa adults and Amblyseius swirskii adults and eggs. However, it is slightly to moderately harmful to adult Phytoseiulus persimilis. There is no information concerning impact on other life stages of these beneficial insects or on Eretmocerus eremicus or Amblyseius californicus. While Judo has a reported residual control of 20-30 days, depending on the pest species, it has only short residual effects (low persistence) on some of the beneficial species. Persistence is 2-3 weeks for P. persimilis and 0 weeks for A. swirskii and E. formosa, but has not been determined for A. californicus or E. eremicus.

Spiromesefin is a lipid biosynthesis inhibitor in the class tetronic acids and can be rotated with all other labeled miticides for resistance management purposes. It affects water balance in the insect, resulting in desiccation. Feeding stops after 1-2 days and death occurs 4 -10 days after treatment. While no injury has been reported on poinsetia, there is an expanded list (not yet on the label) of plants that show sensitivity to Judo. Other crops require the use of lower rates. Both lists are included on the Judo Product Information Bulletin. Growers are advised to check for phytotoxicity on other crops, as not all crops have been included in the manufacturer's tests.

Reprinted from "New Greenhouse Miticide/Insecticide has Potential for Use with Biological Control" by Betsy Lamb, NYS IPM in the Spring 2007 edition of Ornamental Crops IPM E-newsletter from Cornell University.

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