Effectiveness of imidacloprid, spirotetramat, and flupyradifurone to prevent spread of GLRaV-3 by grape mealybug, Pseudococcus maritimus (Hemiptera: Pseudococcidae)

Pseudococcus maritimus status as an economic pest increased substantially after it was identified as a key vector of most grape vine leafroll-associated viruses (GLRaVs). Of these viruses, GLRaV-3 is the most economically destructive. Current control recommendations for slowing the spread of GLRaVs include one to two applications of insecticides to reduce vector populations. Systemic insecticides require the insect to feed before death or paralysis occurs. It was unknown if systemic insecticides could paralyze or kill P. maritimus quickly enough to reduce their ability to vector GLRaVs. Hence, we tested imidacloprid, spirotetramat, and flupyradifurone to see if these insecticides would have any effect on P. maritimus’ efficiency to vector GLRaV-3 on treated grapevines. We conclude that these systemic insecticides do not convey any additional protection to grapevines. However, these insecticides are still useful for reducing vector populations and indirectly reduce the potential spread of GLRaVs among vines in vineyards.