Avermectins, are pesticides of fermentation products with high efficacy and low toxicity and play important roles in food and agricultural product safety, animal and human health. Ivermectins, the derivatives of avermectins, are used to treat Onchocerciasis, also known as River Blindness. Thanks to these discoveries, more than 200 million Africans are lucky to be exempted from blindness. Great efforts have been made on better understanding of the microbial production system of avermectins through genetic en...