Bacillus thuringiensls var. Israelensis for Control of Fl00Dwater Mosquitoes, 1981

Two commercial formulations of BaciIlusthuringiensis var. Israelensis were evaluated at different water temperatues in small-plot field trials for control of Aedescanadensis, A. stimulans, and Psorophoraferox at Tuskegee National Forest, Macon Co., AL. Both materials were compared with Abate 4-E and untreated controls. The area surrounding the standing water in which the tests were carried out was dominated by loblolly pine and mixed hardwood species including tulip poplar, sycamore and water oak. All tests were conducted in circular, plastic-sided, open-bottom pools (ht = 50 cm) delimiting a surface area of 1 m2. Each pool was pressed into the substrate and secured in place with iron rods, preserving the natural bottom conditions. A polyvinyIchloride cylinder (dia = 10 cm,length = 30 cm) was attached to a wooden stake within each test plot and positioned with the lower end (covered with muslin screen) in contact with the substrate, providing a column of water virtually identical to that of the natural pool. Prior to treatment, 20 III- and IV-stage mosquito larvae of a given species were placed in each test cylinder, eliminating predation and providing a convenient means by which mortality could be acurately assessed following treatment. Water temperature was recorded immediately prior to each test. Treatments and rates were randomly assigned to test plots and were replicated 3 times/test. Materials were applied to the entire surface within each test plot with 1 gal compressed-air hand sprayers at 40 psi.