Effects of milbemectin acaricide on mortality rate of agromyzid leafminer, Liriomyza trifolii (Burgess), and its larval parasitoid, Diglyphus isaea (Walker) (Hymenoptera: Eulophidae)

The acaricide milbemectin causes high mortality of newly hatched larvae of the agromyzid leafminer, Liriomyza trifolii (Burgess) on kidney bean plants. A similar effect is observed with use of emamectin, which, like milbemectin, is derived from chemicals produced by soil bacteria. Most of the 1- and 2-day-old leafminer larvae died after application of milbemectin at 20 ppm. Even at 7.5 ppm, significantly fewer larvae grew to pupa compared to controls. Use of milbemectin did not have any adverse effect on development of the parasitoid Diglyphus isaea (Walker) during the larval and pupal stages nor on the survival rate of the emerged adult wasps. These results indicate that milbemectin can be integrated into IPM programs to control both L. trifolii and mites.