Mode of Action of Sefina

With the recent Section 18 permit to use Sefina insecticide for control of lygus bugs in strawberry, a number of growers and PCA's have approached both of us concerning the mode of action of Sefina, of which the active ingredient is afidopyropen.

From the paper included below we find that the mode of action is as follows:

"A recent study revealed that afidopyropen modulates the transient receptor potential vanilloid (TRPV) channels in insect chordotonal organs. Chordotonal organs, which are unique to insects and crustaceans, are mechano-sensors, which are located in the joints of body segments and provide information about relative rotation of body parts. Hyperactivation and eventual silencing of TRPV channels by afidopyropen perturbs function of chordotonal organs and leads to loss of coordination, which, in turn results in inability to feed, desiccation and eventual death"

Put another way, the mode of action is basically similar to an inner ear infection or what one can experience from an excess of alcohol consumption, in that the affected insect has a loss of coordination and balance. That makes them starve to death because they can't really attack the fruit again or makes them susceptible to predation.

It is valuable to point out that Sefina (afidopyropen) does have translaminar efficacy in the plant, but it does take time as you see with aphids in the paper. It is interesting to note that there is no downward movement of the chemical in the plant, they observed upward movement. 

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