Emamectin benzoate: a novel avermectin derivative for control of lepidopterous pests

Emamectin benzoate (MK-0244) is a novel semi-synthetic derivative of the natural product abamectin in the avermectin family of 16-membered macrocylic lactones. This epi-methyl amino derivative has unprecedented potency against a broad spectrum of lepidopterous pests with LC90values ranging between 0.001–0.02 ug/ml in ingestion-based foliar spray assays. Emamectin benzoate is ca. 1,500-fold more potent against certain armyworm species, and 2to 5-fold more potent against diamondback moth, Plutella xylostella (L.), than abamectin. It is 18to 80,400-fold more potent against P. xylostella, cabbage looper, Trichoplusia ni (Hubner), and beet armyworm, Spodoptera exigua (Hubner), than other new insecticides, such as fipronil, chlorfenapyr, and tebufenozide. In the field, the compound is very effective at controlling all lepidopterous pests of cole crops at low use rates (8.4 g ai/ha). The mode of action is similar to abamectin (GABA and glutamate-gated chloride channel agonist) and is not cross resistant with any other compound currently used commercially. The first registrations for the compound on cole crops in the U.S. and Japan are anticipated for 1997. An overview of its potential for control of lepidopterous pests in cole crops is provided.