|GHIMIRE, MUKTI - Animal And Plant Health Inspection Service (APHIS)|
|MYERS, SCOTT - Animal And Plant Health Inspection Service (APHIS)|
|PHILLIPS, THOMAS - Kansas State University|
Submitted to: Journal of Stored Products Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/2/2015
Publication Date: 1/1/2016
Publication URL: http://handle.nal.usda.gov/10113/62730
Citation: Ghimire, M.N., Myers, S.W., Arthur, F.H., Phillips, T.W. 2016. Residual efficacy of deltamethrin and ß-cyfluthrin against Trogoderma variabile and Trogoderma inclusum (Coleoptera: Dermestidae). Journal of Stored Products Research. 66:6-11. doi: 10.1016/j.jspr.2015.12.002.
Interpretive Summary: Dermestid beetles can infest mills and warehouses but there is little information on susceptibility of these insects to insecticides that are currently being used to control stored-product insects. We exposed larvae and adults of the warehouse beetle and the larger cabinet beetle to three application rates of Suspend® and two rates of Tempo® SC Ultra. There was little difference in adult control with the different rates of insecticides, and both insecticides generally killed 90 to100% of the exposed adults for up to three months after the insecticide was applied. Larvae of both species were harder to kill compared to adults. Mill managers can use the results to direct control towards the larvae stage rather than the adult, and improve pest management programs for dermestid beetles.
Technical Abstract: Trogroderma variabile Ballion, warehouse beetle, and Trogoderma inclusum LeConte, larger cabinet beetle, are dermestid pests of stored products. A series of laboratory bioassays were conducted to evaluate residual toxicity of the pyrethroids ß-cyfluthrin and deltamethrin, applied on a concrete surface substrate for control of adults and larvae and adults of both species, to provide initial baseline susceptibility data for dermestids. Commercial formulations were applied at calculated deposition rates of 8, 16, and 24 mg active ingredient [AI] per m2 for deltamethrin and 10 and 20 mg active ingredient [AI] per m2 for ß-cyfluthrin. Ten adults or larvae of either species were introduced individual untreated and treated arenas at 0, 0.5, 1, 2, and 3 mo. post-treatment. Adult mortality was evaluated after 4 d of exposure with no food provided, and larval mortality was assessed 30 d after exposure with provision of food. Adult mortality of both species exposed to both insecticides ranged from 73.3 ± 6.7 to 100% depending on exposure interval. Larval mortality ranged from 18.3 ± 5.4 to 96.7 ± 2.1% on arenas treated with deltamethrin, and was significantly lower than adult mortality (P < 0.001) at bioassays conducted at 2 and 3 mo. post-treatment for both species at all three rates. Larval mortality on arenas treated with ß-cyfluthrin ranged from 13.3 ± 7.1 to 71.7 ± 4.8%, and was always lower (P < 0.001) at all exposure times at both rates for both species. There were only 4 out of a possible 20 comparisons with a significant difference (P < 0.05) between the three rates of deltamethrin and no occasions where there was a significant difference in mortality between the two rates of ß-cyfluthrin. There were three occasions where mortality of T. inclusum adults or larvae was greater than T. variabile, and one occasion with the reverse, for exposures with deltamethrin. Results show larvae of both species were more tolerant than adults, and larvae could be used as an indicator stage for future studies of insecticidal susceptibility of dermestids.