Apple, Effects of Insect Growth Regulators on Stethorus Punctum, 1992

Abstract

Abstract Experimental sprays were applied to 2 tree plots each consisting of a ‘Golden Delicious’ and a ‘Rome Beauty’ tree that were replicated 4 times. Treatments were blocked according to a precount of the ERM population on ‘Golden Delicious’ trees on 10 Jul. These trees were planted 24 x 30 ft apart and were 30 years old. Treatments were applied with a truck-mounted John Bean sprayer, 35 gpm pump, equipped with a handgun to thoroughly wet the trees. Approximately 6 gals of spray were applied per tree (400 gal/A). All treatments were applied at 14 day intervals on 13 and 28 Jul, and 11 and 25 Aug. During the season, regular maintenance fungicides of Benlate, Captan, Penncozeb, Rubigan were applied to all plots. Maintenance insecticides were applied on 8 Jun for aphids (Swat 8EC 1 pt/100 gal) and on 24 Jun (Penncap-M 2F 1 pt/100 gal + Asana XL 0.66EC 0.5 oz/100 gal) for tufted apple budmoth control and to stimulate ERM populations. ERM populations were evaluated weekly by counting mites on 25 leaves/tree, 100 leaves/treatment from the ‘Golden Delicious’ trees only. Effect of treatments on SP was evaluated on the ‘Golden Delicious’ trees by separate 3 min counts of adult, larval and pupal stages around the periphery of the tree. Only pupae that had not yet eclosed were counted. Pupal mortality was evaluated by bringing into the lab approximately 200 non-eclosed pupae from the ‘Rome Beauty’ trees of each treatment on 28 Aug. These pupae were checked for eclosion or mortality every 2-3 days for 10 days. Each pupa from each treatment, regardless of the collection tree, was considered a replicate for analysis.