Insect Control, Highland, N.Y., 1988

Abstract

Abstract Treatments were applied to 8-tree plots replicated 3 times in a randomized complete block design. All treatments were applied dilute to run-off using a high-pressure handgun sprayer at 400 psi delivering 3.1-4.2 gal spray/tree or 300-403 gal/acre. Trees were 24 yr old, 10 ft high, spaced 15 by 30 ft, and on the EMU rootstock. The XRD-473, XRD-473 + Lorsban, Lorsban, Guthion 3 F, and Guthion 35 W treatments were all tested in a seasonal program with sprays applied at pink, 4 May; petal fall, 23 May; and in cover sprays on 7 Jun, 21 Jun, 6 Jul, 23 Jul, 8 Aug, and 23 Aug. Pounce and Pounce/ALT were both applied at pink and petal fall then followed by cover sprays of Imidan on j Jun, 6 Jul, 23 Jul, 8 Aug, and 23 Aug; Thiodan was substituted for aphid control on the 21 Jun cover. Further treatments included Orthene at pink, followed by Guthion at petal fall and on 21 Jun, Danitol on 7 Jun, and Guthion at a reduced rate combined with Sevin on 6 Jul, 23 Jul, 8 Aug, and 23 Aug. A similar treatment used the same schedule except that Larvin was substituted for Sevin; Danitol at pink and 7 Jun, followed by Guthion at petal fall and 21 Jun and Guthion at a reduced rate combined with Sevin and Surfel applied on 6 Jul, 23 Jul, 8 Aug, and 23 Aug. A final treatment was the same as the preceding treatment except that Larvin was substituted for Sevin. Additional applications over the entire block included Difolatan 80 S 12.5 lb/acre, 6 Apr; Dithane M45 80 W 6 lb/acre + Rubigan 1 EC 6 oz/acre, 20 May, 27 May, and 9 Jun; and Dithane M45 80 W 6 lb/acre, 30 Jun. Naphthaleneacetic acid (Kling-tite formulation) was applied in thinning sprays on 27 May using up to 15 ppm depending upon the cultivar and fruit set. European apple sawfly, plum curculio, and rosy apple aphid were evaluated prior to the “June drop” by examining all of the apples in 25 fruiting clusters on one ‘McIntosh’ and one ‘Cortland’ or on one Golden Delicious’ and one ‘Cortland’ tree/plot on 6 Jun. Apple and spirea aphids were evaluated by examining 25 terminals on one ‘McIntosh’ tree/plot on 10 Jun and 24 Jun and on one ‘McIntosh’ and one ‘Cortland’ tree/plot on 16 Jun. Spotted tentiform leafminer was evaluated 19 Sep by counting the mines on 25 ‘Greening’ leaves/plot on 19 Sep. Insect damage to fruit was assessed at harvest by examining 100 apples/cultivar/plot from ‘Jersey Mac,’ 5 Aug; ‘McIntosh,’ 19 Sep; and ‘Golden Delicious,’ 7 Oct. ‘Golden Delicious’ fruit finish was evaluated using a russet rating from 0 (best finish) to 3 (worst finish). Rainfall was less than normal during April, June, and August, but above normal during July. Temperatures were above normal during June, July, and August. An extended bloom period with certain cultivars in bloom while the petals had fallen on others, resulted in greater than normal insect pressure especially from European apple sawfly and plum curculio. The extremely warm summer temperatures resulted in significant third-brood white apple leafhopper and spotted tentiform leafminer pressure.