Residual Mortauty of Twospotted Spider Mite From Agri-Mek Plus Various Adjuvants, 1992

This study was conducted using treated leaves from a mature ‘Delicious’ orchard at the Tree Fruit Research & Extension Center in Wenatchee, Washington. The four treatments (Agri-Mek 0.15EC 11 g Al/acre; Agri-Mek 0.15EC llg Al/acre plus 0.25% Volck Supreme Oil; Agri-Mek 0.15EC llg Al/acre plus Sylgard; and an untreated check) were applied on 1 Jun. Treatments were applied with a handgun sprayer operated at 250 psi to the point of drip. Ten leaves were collected on each bioassay date. A 2-cm leaf disk was cut from each leaf and floated upside down in a jelly cup of water and cellucotton. Ten adult female TSM were loaded on each leaf disk and evaluated for mortality after 72 h at 25°C. Dead and moribund mites were classed as dead, and mites that were not found on the leaf disk were not included in the analyses. Post-treatment assays were conducted on leaves collected at ca. weekly intervals. Treatment mortality data were corrected for check mortality with Abbott's formula.