Comparative selectivity of acaricides to the predatory mites of Phytoseiulus persimilis and Neoseiulus californicus (Acari: Phytoseiidae)‎

Abstract EN

To address suitable acaricides, the selectivity and efficacy of five acaricides of bifenazate, cyflumetofen, pyridaben, pyridaben+clofentezine and spirodiclofen to two predacious mites Phytoseiulus persimilis persimilis (Athias-Henriot), Neoseiulus californicus (McGregor) (Acari: Phytoseiidae) and its prey Tetranychus urticae Koch.

(Acari: Tetranychidae) were tested.

The general selective toxicity ratio (G.S.T.R.) of five acarcides which combines the selectivity ratios of both LC50 and LC90 levels was estimated.

Results revealed that both spirodiclofen and pyridaben +clofentezine had the highest toxicity on both predators, P.

persimilis and N.

californicus.

The values were 1.81 and 1.69 ppm for P.

persimilis and 2.69 and 1.66 ppm for N.

californicus at LC50 and LC90 levels, respectively.

However, cyflumetofen have the lowest toxicity values for each of P.

persimilis and N.

californicus with the same values of 0.001 ppm at LC90 levels.

Based on the G.S.T.R., cyflumetofen, and bifenazate recorded harmless performances, whereas the other tested compounds recorded harm effects on the two used predators.

The results of field studies showed that the greatest percent reductions of spider mite population on kidney bean plants were obtained by cyflumetofen (93.4 %) in China and pyridaben (89.3%) in Egypt.

On other hand, pyridaben treatment gave the highest significantly percentage of reductions of 98.2 and 96.7 % against the two tested predators, respectively, under greenhouse conditions.

However, the lowest percentage of reduction was obtained by the two treatments of bifenazate and cyflumetofen against the previous two predators with no difference effect between the two acaricides.

It could be concluded that the recommended acaricides to control spider mites are bifenazate and cyflumetofen, based on the efficacy and toxicity with no or less harmful on associated predatory mites.