Orange Tortrix Larva Control, 1984

Single treated rows, 200-250 ft long and 9 ft apart, were alternated with untreated rows of the same length. Each treated row was divided into 4 or 5 subunits. Larval counts from each subunit were compared with counts from adjacent subunits in the untreated rows on each side of the treated row. The insecticides were applied as sprays with a vertical boom in 115 gal of water per acre at 150 psi. The first spray was applied on 18 Jun ’84, which was ca. 2 wk after the peak catches of male orange tortrix moths in pheromone traps (ca. 150/trap/week). Heavy rains on Jun 19 and 20 (total 1.7 inches) plus very low larva populations on 26 Jun caused us to reapply the sprays on 2 Jul. No rain fell during the following week. Treatments were evaluated on 9 Jul by examining 50 primocane tips in each subunit. The number of larval-infested tips was recorded.