Apple, Leafroller Control, 1976

Abstract

Abstract Insecticide treatments applied as full-season dilute sprays in a block of 12 year-old trees (MM 106) were evaluated for leafroller control and monitored for any change in mite populations. Single-tree plots were replicated using 2 Staymans, 1 Winesap, and 1 York. Trees were sprayed to runoff using a Bean high pressure sprayer (35 gal/min pump) operating at 540 psi on the following dates: 18 June (all plots); 30 June (plots 1-11); 2 July (plots 12-14); 20 July (all plots); 10 Aug (all plots); 31 Aug (all plots except Shell SD 43775). Cover sprays (rate/100 gal/acre) for ail trees included: 25 Mar, Dikar 6.0 lb + Systox 10.0 oz (both sides); 1 Apr, Dikar 6.0 lb (both sides); 16, 21 Apr, Dikar 6.0 lb (one side); 29 Apr, Guthion 1.5 lb + Systox 10.0 oz + Dikar 6.0 lb (one side); 6 May, Guthion 1.5 lb + Systox 10.0 oz + Dikar 6.0 lb (both sides); 18, 26 May, Guthion 1.5 lb + Dikar 6.0 lb (one side); 1, 10 June, Guthion 1.5 lb + Phosphamidon 6.0 oz + Dikar 6.0 lb (one side); 2 July, Polyrom 6.0 lb (one side); 26 July, Phaltan 5.0 lb (both sides); 11 Aug, Captan 5.0 + Karathane 1.0 lb (both sides). Mean temperatures were average for June (72.9°F) and below average for May (62.3°F), July (74.3°F), Aug (71.7°F), and Sep (66.8°F). Rainfall in inches was below normal in May (3.6) and above normal for June (6.8), July (5.2), Aug (5.4), and Sep (3.9). Mite counts were made by examining 80 leaves (20 leaves/tree) on 13 July and 13 Aug. Leafroll counts were made by examining each tree for 15 minutes on 19-20 Aug. Each treatment was evaluated by examining 200 apples (50 per tree) on 22, 25 Oct.