ingestion, and subsequent insect death 2–4 days later. It has registered uses in many countries on fruits, vegetables, cereals, tree nuts, oilseeds, herbs and tea.
Emamectin exists in various forms: as emamectin (free base), as emamectin benzoate salt (MK244)
and as emamectin hydrochloride (MK243). Emamectin benzoate exists as the anhydrous and various
hydrated forms having different crystal morphologies. The amount of water is nonstoichiometric.
[Merck Index]. Experiments described in this evaluation were carried out with various hydrate forms
of the emamectin benzoate salt.
Emamectin benzoate (MK-0244) is the common name for (4"R)-4"-deoxy-4"-
(methylamino)avermectin B1 benzoate (MAB1), which is a mixture of 4"R)-4"-deoxy-4"-
(methylamino)avermectin B1a benzoate (MAB1a or emamectin B1a benzoate) and 4"R)-4"-deoxy-4"-
(methylamino)avermectin B1b benzoate (MAB1b or emamectin B1b benzoate). The avermectins in
emamectin benzoate are specified as a ratio MAB1a:MAB1b = 90:10 (w/w) and differ by a methylene
group at the C26 alkyl substituent: –CH2CH3 for MAB1a and –CH3 for MAB1b.