Apple, Insect Control, Hudson Valley, Highland, NY, 1986

Abstract

Abstract Treatments were applied to 8 tree plots replicated 3 times in a randomized complete block design. Baythroid, TD 2207, and Lorsban treatments were applied on 28 Apr (pink), 10 May (petal fall), and in cover sprays on 26 May, 10 Jun, 23 Jun, 7 Jul, 21 Jul, 5 Aug, and 19 Aug. Orthene was applied 27 Apr and 10 May followed by Danitol in all remaining cover sprays, while Brigade was applied 28 Apr and 10 May followed by Thiodan in remaining cover sprays. Dimilin treatments were applied 28 Apr, 23 Jun, and 5 Aug with Guthion applied on remaining forementioned spray dates. Larvin was applied along with Guthion at the 4 oz rate on 10 May, and alone at the 8 oz rate on 23 Jun and 5 Aug, while Guthion was applied alone at the 8 oz rate on 28 Apr, 26 May, 10 Jun, 7 Jul, 22 Jul, and 19 Aug. Danitol was applied once at the 10 oz rate on 10 May, and in 4 applications at the 4 and 2.6 oz rates on 27 Apr, 10 May, 23 Jun, and 5 Aug. Kelthane treatments were applied 13 Aug. All treatments were applied dilute to runoff using a high-pressure handgun sprayer at 400 psi delivering 4.2 gal spray per tree or 403 gal/acre. Trees were 22 years-old, 12 ft high, spaced 15 by 30 ft, and on the EMII rootstock. Additional applications over the entire block included: Difolatan 80S 16 lb/acre 9 Apr; Bayleton 50W 3.5 oz/acre, 5 May; and Dithane M-45 78WP 4V2 lb per acre, 5 May and 20 May. Naphthaleneacetic acid was applied in thinning sprays on 15 May using from 5 to 15 ppm depending upon the cultivar. White apple leafhopper was evaluated by counting nymphs on 25 leaves from one ‘Greening’ tree per plot on 23 Jul and 6 Sep. Spotted tentiform leafminer was evaluated 15 Aug by counting mines on 25 leaves from one ‘Greening’ and one ‘Cortland’ tree per plot. Apple aphids were evaluated by examining 25 termianls on one ‘Mcintosh’ tree per plot on 13 Jun and 27 Jun. Woolly apple aphids were evaluated by examining 25 terminals from one ‘Mcintosh’ tree per plot on 6 Sep. European apple sawfly and plum curculio were evaluated prior to Jun drop by examining all fruits in 50 fruiting clusters on one ‘Mcintosh’ tree per plot on 29 May. Insect damage to fruit was assessed at harvest by examining 100 fruits per cultivar per plot from ‘Mcintosh’ 6 Sep, and ‘Golden Delicious’ 1 Oct. Insect pressure during the season was very great for all species evaluated except apple maggot and external lepidopterous fruit feeders, e. g. leafrollers, for which we were unable to determine the predominant species causing injury. An early spring resulted in an early bloom lasting longer than normal. During bloom, warm periods were often followed by sudden temperature drops, and frost damage occurred on at least 2 occasions in low lying areas of the valley. Rainfall was above average throughout Jun and Jul but below average in other months, while temperatures were generally below normal.