Question: Last week I discovered more than 30 dead or dying fig beetles under a desert willow that grew from seed near the foundation of my home.ย We had decided to leave the tree, and it has grown at an angle away from the home and is now about 6 years old and as tall as the house (maybe 14-16 feet).ย I picked up the beetles, but every day since there has been a similar number of dead or dying beetles. So in the past week we have had more than 200 dead beetles and dozens of dead or dying bees and wasps, mostly carpenter bees, a few blue mud daubers and various other striped bees and waspsย I could not identify. My first thought because of the treeโs close proximity to the house is that the pesticides that are applied every other month may have been systemic and been absorbed by the tree and put out in its nectar and pollen, especially since the bugs are all nectar drinkers and are all on their back with their legs twitching the way they do when killed by pesticides. I called the pest-control company and they insisted this was not the case. My exterminator uses bifenthrin, which according to info I can find is not systemic.ย All the info I can find seems to indicate the fig beetle mates and leaves their eggs in turf, so my thought that they were mating and reaching the end of their life cycle in my tree seems inaccurate.ย I worry about this because we were planning on putting in a raised vegetable gardenย in that corner of the yard.
A:ย Bifenthrin is not a systemic but rather a contact poison and an effective tool against a variety of insect pests. It will kill all of the insects you mentioned and is toxic to bees. It shouldnโt be sprayed on or near flowering plants, to protect pollinators and other nectar feeders. You will need to avoid spraying bifenthrin in a raised vegetable garden, so you might want to ask your pest-control company which pests they are seeing in that part of your yard to determine if they might be pests of your garden. While you are at it, you might evaluate the need for a regular insecticide treatment.ย Sometimes a calendar spray is recommended, but many times it is just recreational pesticide use. It really depends on the pest problem you are addressing.Make sure you know what pests they are seeing and ask them to show you specimens so you arenโt paying and spraying for no good reason.
Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed toย tucsongardensage@gmail.com
