Codling Moth Control with XRD-473,1989

Abstract

Abstract Cover spray programs of the insect growth regulator (IGR) XRD-473 by itself and in combination with Lorsban were compared to a standard Guthion program. Sprays were applied dilute by handgun operating at 200 psi to 28-yr-old pear trees. Treatment rates given assume a spray volume of 400 gal/acre. Each treatment consisted of 4 single-tree replicates arranged in a randomized complete block. Streptomycin was applied to the whole block for control of fireblight. Cover sprays were timed to codling moth phenology (see Washington State University Extension Bulletin 1072). The IGR XRD-473 was applied 100 to 150°D (base 50°F) earlier than organophosphate cover sprays to coincide with the beginning and peak of egglaying activity. Fruit (25/tree) was checked in mid-season at the end of the first CM generation and at harvest. Stings as well as entries were recorded. The harvest fruit sample was also checked for pear psylla as well as pear rust mite russet. Leaf samples were taken 10 Jul and 21 Aug and checked for PP, spider mites and PRM. Ten terminals were sampled on a tree by removing a leaf from the top, middle and bottom of a terminal (30/leaves/tree; 120/treatment). Mites as well as PP immatures were removed from leaves with a mite brushing machine onto a sticky glass plate and counted under a stereo microscope.