title: Toxicity and horizontal transfer of 0.5% fipronil dust against Formosan subterranean termites.
abstract: The toxicity and horizontal transfer of a new formulation of fipronil, 0.5% fipronil dust, was tested against Coptotermes formosanus Shiraki in the laboratory. The formulation was applied in three different ways: 1) Directly applied to termites (donors) and mixed with untreated termites (recipients) at three ratios, viz., 50 donors: 50 recipients, 20 donors: 80 recipients and 10 donors: 90 recipients. 2) Applied onto the surface of 3 mm thick sand or soil substrate in a petri dish and then topped with another 3 mm thick sand or soil layer whereupon termites were released. 3) Applied to the inner surface of a tube (either 5 cm or 15 cm long) that connected two foraging dishes, one containing dry sand and the other moist sand plus a wood block and termites were released into the dry sand dish. All donors and >93% of the recipients were dead by 42 h after treatment in the direct treatment experiment. Significant mortalities of both donors and recipients were observed at 5 h after treatment at all donor: recipient ratios. During this period, the mortality of the recipients (but not donors) at 10:90 was significantly lower than those at the other two ratios. All termites were dead at 65 h after exposure (HAE) on the sand treatment and at 190 HAE on soil treatment. More than 96% mortality was observed at 40 HAE on the sand treatment as compared with only 6% mortality onsoil treatment during the same time period. In the tube treatment experiment, > 97% mortality was observed at 90 h after release for both tube lengths as compared with < 3% mortality in controls. About half of the termites were dead by 15 h after release regardless of the tube length. Our results showed that 0.5% fipronil dust is nonrepellent and readily transferred from treated to nontreated termites.
authors.affiliation: Department of Entomology, Louisiana State University Agricultural Center, 404 Lif e Sciences Building, Baton Rouge, LA 70803, USA.
authors.forename: Bal K
authors.initials: BK
authors.lastname: Gautam
authors.forename: Gregg
authors.initials: G
authors.lastname: Henderson
authors.forename: Robert W
authors.initials: RW
authors.lastname: Davis
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D004391:Dust; D007300:Insect Control / Q000379:methods*; D007306:Insecticides / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity*; D020049:Isoptera / Q000187:drug effects*; D011720:Pyrazoles / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity*; D012822:Silicon Dioxide / Q000737:chemistry; D012987:Soil / Q000737:chemistry
chemical_list: D004391:Dust; D007306:Insecticides; D011720:Pyrazoles; D012987:Soil; D012822:Silicon Dioxide; C082360:fipronil