Control of Dermatobia hominis larvae by manual extraction is effective and does not cause abscesso

ABSTRACT: In order to study alternative ways of control of Dermatobia hominis fly larvae, three processes were tested: T1, cypermethrin 5% + chlorpyrifos 7% + citronellal 0.5% (Pour on); T2, trichlorfon powder dissolved at 2% in burnt oil passed on the nodules; T3, manual larva extraction. The study was conducted at Instituto de Zootecnia in Nova Odessa, São Paulo State, Brazil. In a dairy herd of 176 animals, 29 with at least one larvae were found, distributed in the three treatments. Each treatment’s efficacy percentage was based on the number of live botflies present after 14 days. The animals were observed on days +4, +7, +14 and +21, and new botflies and abscesses were annotated. All treatments presented high effectiveness (above 98%). New botflies were already seen in the first week after applying the three treatments, and on day 21, two abscesses in each chemical treatment were observed. Larva extraction was 100% effective, with no originating abscesses, and should be encouraged in small and medium-sized properties and those with resistant botflies to chemical products.