Black Vine Weevil Larvicide Drench Test, Wooster, Ohio, 1986

Abstract

Abstract Taxus growing in 7.6-liter containers with a hardwood bark and peat medium were obtained from an Ohio nursery for evaluating the efficacy of insecticide drenches against black vine weevil larvae. Plants were maintained under normal nursery conditions throughout the test period and received 1.3 cm of overhead irrigation every Monday, Wednesday, and Friday. Containers were drenched with insecticide 2 Jun or 3 Sep, using a total of 946 ml of solution per container, delivered in 2 equal applications. Each insecticide treatment was replicated 5 times. Black vine weevil eggs were obtained from adults held at 22°C and at least 80% RH at a photoperiod of 16:8 (L:D). On 14 Jul, 6 wk after the Jun application, all containers received 400 brown eggs placed 2.54 cm beneath the surface of the potting medium. Treatment effects were evaluated in November, when larvae were approaching maturity, by removing the plant and medium from each container and counting the number of larvae.