Muscarinic Agonists as Insecticides and Acaricides

A series of known agonists of the mammalian muscarinic receptor were prepared and evaluated for their insecticidal potential. It was discovered that pests such as Nilaparvata lugens (brown planthopper), Nephotettix cincticeps (green leafhopper), Tetranychus urticae (two‐spotted spider mite) and Aphis gossypii (cotton aphid) were particularly sensitive to most of these compounds. Several analogs proved to be extremely active, surpassing commercial standards in some of the laboratory bioassays. These compounds exhibited a range of potencies for the insect (Musca) muscarinic receptor. Addition of GTP significantly reduced the affinity of the most potent analog for the Musca mAChR, indicating the compound functions as an agonist in insect tissue. Regression analysis indicated that significant relationships exist between displacement of [3H]QNB at the Musca muscarinic receptor and whole organism toxicity to three insect and one mite species. The results suggested that the insect muscarinic receptor represents a viable target site for insecticidal action. © 1997 SCI.