Interaction between ticks (Acari: Ixodidae) and pathogenic nematodes (Nematoda): susceptibility of tick species at various developmental stages

Samish, M.; Alekseev, E.; Glazer, I.

The virulence of entomopathogenic nematodes (Steinernematidae and Heterorhabditidae) to tick species under laboratory conditions is reported. The susceptibility of larval, nymphal, and adult stages of the ticks Hyalomma excavatum (Koch), Rhipicephalus bursa (Canestrini & Fanz), and R. sanguineus (Latereille) to 2 strains of Steinernema carpocapsae and 3 strains of Heterorhabditis bacteriophora were compared in laboratory assays. Preimaginal stages of ticks were found to be more resistant to the nematodes than were adult ticks which exhibited 80-100% mortality in a dish containing 5,000 infective juveniles of H. bacteriophora IS-3 or IS-5 strains isolated in Israel. These 2 strains were found to be much more virulent to unfed adult ticks than were the other isolates. No marked difference was found between engorged ticks and unfed adults of R. sanguineus or H. excavatum in terms of mortality, whereas engorged males and unfed females of R. bursa were significantly more susceptible than unfed males or engorged females.