STOP – Don’t kill that bug! One of the best beneficial bugs controlling vegetable pests in your garden, looks just like a housefly. I’m talking about the Tachinid flies that often fall victim to mistaken identity. These are extremely beneficial in your garden both as pollinators and as parasitoids (or parasites that kill their hosts). The adult Tachinid fly closely resembles a common housefly but if you see it in your garden, especially feasting on your flowers’ nectar – STOP – since houseflies do not eat nectar.
Also, these flies can be recognized by their numerous dark bristly hairs covering their abdomens which aid them in their role as a pollinator. There are numerous species of Tachinids but the majority of them lay their eggs directly upon the bodies of their hosts. Some of their victims include important pests of vegetables such as the cabbageworm, cucumber beetle and Squash bug. When these eggs hatch, the larvae (or maggot) will tunnel into the host’s body and completely consume them from the inside out before emerging as adults.
Unfortunately, one of the biggest predators of this hard- working beneficial is…US (humans) since they so closely resemble houseflies, which breed in filth. So, before grabbing a flyswatter or running for an insecticide, try to observe what’s actually going on. Is the insect you see actually causing damage to your plants? If you’re seeing holes chewed in your leaves, it is not being caused by this insect since they don’t have chewing mouthparts. Therefore, the presence of another leaf-eating pest may actually be the reason why this insect was attracted to your garden in the first place.
This is another reason why it is so important to try to figure out what is actually going on in the garden. Many gardeners often blame the damage on whatever they happen to find in their yard and many of these good guys are often just in the “wrong place at the wrong time”. Learning to identify and protect good bugs as well as learning to tolerate some pests (as a food source for your beneficial) is one of the best ways to maintain a healthy balance in your yard. You can increase the incidence of this beneficial in your garden by planting plenty of nectar-rich flowers in the aster or carrot family. These include plants such as Shasta daisies, dill, fennel, yarrow and cosmos.
Dr. Winky is our very own Sloat staffer Helen Winkler. Helen is one of our long-time nursery professionals at our Sloat Blvd store and is a certified arborist and a CCNPro (California Certified Nursery Professional).