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United States Department of Agriculture

Agricultural Research Service


item Lapointe, Stephen
item McKenzie, Cindy

Submitted to: Entomological Society of America Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: March 30, 2002
Publication Date: November 1, 2002
Citation: Lapointe, S.L., Mckenzie, C.L. 2002. A particle film enhances citrus tree growth and deters oviposition by the diaprepes root weevil. Entomological Society of America Proceedings.

Technical Abstract: Damage by the larvae of the Diaprepes root weevil, Diaprepes abbreviatus, is a primary concern of citrus producers in Florida and the Caribbean because of the difficulty of detecting and monitoring soil-inhabiting larvae in general, and the particularly destructive habits of D. abbreviatus. A hydrophilic formulation of the inert silicate kaolin was tested in a screenhouse for its effect on the behavior of D. abbreviatus. Feeding by adults on treated foliage was reduced by 75 - 84% compared with adults fed untreated foliage. No acute insecticidal activity was detected. Oviposition was completely suppressed on treated foliage in cage studies. While females oviposited more than 19,000 eggs during two trials on untreated foliage, no egg masses were found on foliage treated with the kaolin formulation. Field trials in the absence of D. abbreviatus have demonstrated a postitive effect of kaolin on early tree growth. At Ft. Pierce, trees sprayed for two years with the commercial kaolin product Surround (R) at the recommended rate (3%) were 22% taller and had stem diameters 32 to 36% larger than untreated trees. In infested fields, oviposition by adult weevils on Surround (R)-treated trees was reduced by 73% compared with untreated trees. Problems to overcome include frequency of use due to limited rainfastness, and resurgence of nontarget insect pests (scales). These data include potential for kaolin as a barrier to oviposition in citrus groves and may prove to be an economically viable and environmentally sound component of an integrated approach to control of D. abbreviatus and related root weevils.

Last Modified: 9/2/2015
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