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10-Minute Presentation

Medical, Urban, and Veterinary Entomology

10-min: MUVE, Tick Talks

Laboratory and semi-field studies of biominerals to control the American dog tick, Dermacentor variabilis

Tuesday, November 12, 2024
2:36 PM – 2:48 PM MST
Location: Phoenix Convention Center, 221 C, PCC
Oral Presentation
Most vector-borne diseases in the United States are transmitted by ticks. Rising concerns about resistance to chemical pesticides for some tick species and the public increasing interest in more environmentally friendly, inexpensive biopesticides have stimulated interest in our group in applications in the materials sciences for pest control.Celite 610, a diatomaceous earth (DE) derived from skeletons of diatoms, is a mechanical insecticide that we showed previously was efficacious in killing Ixodes scapularis nymphs and adults in dip and choice bioassays. In this study reported here, we tested the efficacy of DE against D. variabilis nymphs. When D. variabilis nymphs were dipped in DE powder, the estimated median survival times at 30±1°C were 5.00 (4.50, 6.50) h at 50% relative humidity (RH) and 4.00 (3.50, 5.50) h at 70% RH. Two choice bioassays showed that D. variabilis would freely move into the DE when used as a trap, with a median survival time of 3 (2.5, 6) h at 30±1°C and 50±5% RH. A test of the effect of DE on the locomotor activity of D. variabilis nymphs revealed that DE did not significantly impact their movement. Although the D. variabilis nymphs were highly mummified with the DE before dying in the dipping and two-choice bioassays, a semi-field experiment at 30±1°C and 50% RH showed that a dose as low as 0.15 g/m2 of DE can cause mortality in D. variabilis nymphs.