Control of Adult Black Vine Weevil on Nursery Grown Taxus in Connecticut, 1978

Abstract

Abstract A foliar spray program was initiated in June, two weeks after the first adult weevils were found around taxus plants in a commercial nursery in Waterford. The weevil population had been abundant enough in the test area to kill 2-3% of the plants in 1977. Insecticide treatments were timed to prevent weevils from reaching maturation. The time between treatments depended on established residual activity of each chemical on taxus foliage. The test was run on 3-year old plants and the plots were 3 rows (6 ft) wide and 16 plants (32 ft) long. Plots were laid out in a complete block design and randomized four times. Pydrin was applied only once on June 22, Guthion was applied two times, June 22 and Aug 4. Orthene and Ficam were applied four times, June 22, Jul 14, Aug 4 and 25. Insecticides were applied with a hydraulic sprayer developing 50 psi. Foliage was sprayed to runoff and the soil under each plant was moistened with the spray. Weevils were fairly uniformly distributed throughout the test area with a pretreatment count on June 20 showing 18 weevils per plot. Counts were made by counting all weevils under 3 plants in the center of each plot and allowing 3 minutes counting time per plant. Beetles were not removed after counting. A heavy rainfall of 2.45 inches occurred July 3-4, but precipitation for the whole test period was below normal.