Laboratory evaluation of four commercial repellents against larval Leptotrombidium deliense (Acari: Trombiculidae)

Four commercial repellents were evaluated in the laboratory against Leptotrombidium deliense chiggers. Both in vitro and in vivo methods were used to determine repellency of the compounds. The repellents were Kellis (containing citronella oil, jojoba oil and tea tree oil), Kaps (containing citronella oil), BioZ (containing citronella oil, geranium oil and lemon grass oil) and Off (containing DEET). The combination of three active ingredients: citronella oil, geranium oil, lemon grass oil gave the highest repellency (87%) followed by DEET (84%). In vitro repellencies ranged from 73% to 87%. There was no significant difference between the four products. All the repellents had 100% in vivo repellency compared to 41-57% for the controls.