The use of a semiochemical bait to enhance exposure of Amblyomma variegatum (Acari: Ixodidae) to Metarhizium anisopliae (Ascomycota: Hypocreales).
Experiments were conducted to explore the use of a semiochemical bait to enhance exposure of Amblyomma variegatum Fabricius (Acari: Ixodidae) to different formulations of the entomopathogenic fungus Metarhizium anisopliae (Metsch.) Sorok. (Ascomycota: Hypocreales). Initially, the relative efficacies of attraction-aggregation-attachment pheromone (AAAP), made up of o-nitrophenol, methyl salicylate and nonanoic acid in the ratio 2:1:8, 1-octen-3-ol and butyric acid, were evaluated in an olfactometer. Only AAAP and 1-octen-3-ol were found to elicit attractive responses to the tick. Simultaneous release of 1-octen-3-ol and AAAP together with CO(2) from a trap in semifield plots attracted up to 94.0+/-6% of adult ticks from a distance of 6m, and up to 24.0+/-5.1% from 8m. Formulations of M. anisopliae (dry powder, oil, and emulsifiable) applied within the trap baited with AAAP, 1-octen-3-ol and CO(2) resulted in high levels of contamination of the ticks attracted to the traps. However, 48h after autoinoculation, 89.1 and 33.3% of conidia were lost in dry powder and oil formulations, respectively. Emulsifiable formulation showed least loss of propagules (17.1%). Samples of ticks attracted to the baited traps were transferred to plastic basins containing grass and maintained for 5 weeks. The experiment was conducted in rainy and dry seasons. Emulsifiable formulation gave the highest relative tick reduction in both seasons: 54.7 and 46.5% in rainy and dry seasons, respectively, followed by oil formulation (32.0 and 23.8%) and powder formulation (38.0 and 24.4%).
Nchu
F
F
International Centre of Insect Physiology and Ecology, African Insect Sciences for Food and Health, Nairobi, Kenya.
Maniania
N K
NK
Touré
A
A
Hassanali
A
A
Eloff
J N
JN
D000818:Animals; D000898:Antibiosis; D004655:Emulsions; D005260:Female; D006999:Hypocreales / Q000254:growth & development*; D026863:Ixodidae / Q000254:growth & development* / Q000382:microbiology*; D008297:Male; D010572:Pest Control, Biological / Q000379:methods*; D010675:Pheromones / Q000494:pharmacology*; D012621:Seasons; D013983:Tick Control / Q000379:methods*; D013984:Tick Infestations / Q000517:prevention & control / Q000662:veterinary
D004655:Emulsions; D010675:Pheromones