Efficacy of a novel neem oil formulation (RP03™) to control the poultry red mite Dermanyssus gallinae

Dermanyssus gallinae (Mesostigmata: Dermanyssidae) is the most harmful ectoparasite of laying hens, represents an occupational hazard for poultry workers, and a growing threat to medical science per se. There is increasing demand for alternative products, including plant-derived acaricides, with which to control the mite. The present study investigated the efficacy of neem oil against D. gallinae on a heavily infested commercial laying hen farm. A novel formulation of 20% neem oil, diluted from a 2400-p.p.m. azadirachtin-concentrated stock (RP03â ¢), was administered by nebulization three times in 1week. Using corrugated cardboard traps, mite density was monitored before, during and after treatment and results were statistically analysed. Mite populations in the treated block showed 94.65%, 99.64% and 99.80% reductions after the first, second and third product administrations, respectively. The rate of reduction of the mite population was significantly higher in the treated block (P<0.001) compared with the control and buffer blocks. The results suggest the strong bioactivity of neem, and specifically of the patented neem-based formulation RP03â ¢, against D. gallinae. The treatment was most effective in the 10days following the first application and its effects persisted for over 2months. Further studies will aim to overcome observed side effects of treatment represented by an oily layer on equipment and eggs.