Molecular mechanisms of Tetranychus urticae chemical adaptation in hops field

The two-spotted spider mite, Tetranychus urticae Koch is a world-wide agriculture super pest that can feed on > 1,100 plant species in more than 140 families. In West Coast, some perennial specialty crops, such as hops are plagued by spider mite infestations. Hop (Humulus lupulus), as a flavoring and stability agent in beer, is an economically important crop valued at $163 million in Washington State, where produces 90% of all U.S. hops. In most situations, hops growers apply inexpensive disruptive pesticides to suppress the spider mite populations. Unfortunately spider mites have been shown to quickly develop tolerance and/or resistance to these chemicals which directly caused control failure. In order to design the most effective and sustainable spider mite management tactics, our long-term goal is revealing the molecular mechanisms underlying the chemical adaptation of T. urticae in hops field. To achieve our long-term goal, we collected about 100 T. urticae field samples across Washington State during hops seasons 2013-2014. Recent molecular studies revealed a number of target site mutations and detoxification associate genes that involved in the chemical adaptation to common used acaricides, such as Abamectin, Bifenazate, and Pyrethroids. We investigated the distribution of these multiple mutations and relative expression of detoxification related genes in field collected samples compared with the susceptible T. urticae population. The unique mechanisms underpinning the chemical adaptation of Tetranychus urticae in hops field will be discussed.