Q. I have heard that some wasps were introduced in Fort Wayne to kill the emerald ash borers. Where can I get some wasps for my trees?
A. Purdue Entomology specialist Dr. Cliff Sadof was given 1,000 beneficial wasps from APHIS, a division of the U.S. Department of Agriculture that is responsible for invasive insects and plants. These wasps are given to scientists at land-grant colleges such as Purdue University so that the scientists can conduct research that may help eliminate or control a pest. Unfortunately, the wasps are not available to the public.
There are three beneficial wasp species that have been considered for use by scientists. The wasps attack either the eggs or larvae of the ash borer. The wasps released in Fort Wayne by Purdue are ones that attack the larvae of the insect. These tiny wasps, native to regions of China and Russia, do not sting and have no known adverse effects to humans or pets.
Some folks might ask, “Isn’t there a chance these wasps might end up to be a bigger problem – affecting something else – or multiplying beyond control?” There is always a chance that something could go wrong, but preliminary research by APHIS concluded that there was little if any chance that this could occur.
Scientists also concluded that the risk of using the beneficial insects was less than doing nothing at all. The state of Michigan has already lost millions of ash trees.
In an initial economic analysis of emerald ash borers, the USDA estimated that emerald ash borers, if not contained and eradicated, could cause about $7 billion in additional costs to state and local governments and landowners to remove and replace dead and dying ash trees in urban and suburban areas over the next 25 years. Cities in Michigan have reported substantially higher water and electrical use because of the loss of ash as shade trees.
Many introduced insects to control invasive pests are not successful. Only 12 percent of all parasitoid introductions have led to significant sustained control of the target pests. The insects simply don’t make it in our climate. Certainly these wasps won’t die because of a lack of available food.
Significant damage and death of ash trees are occurring in our area, which is why Fort Wayne was chosen for the release of the wasps. Just drive around the city and observe the increased woodpecker damage sprouting on the lower trunks and limbs, and thinning of the tops of all the ash trees. For now, this situation is like a slow-moving hurricane. Most folks knew the pest was arriving, but we are all still amazed at all the damage it can do.
Purdue Extension will continue to inform citizens about emerald ash borer in the years to come. Hopefully, better treatment options will continue to be developed for control of this invasive insect.
Google the words “emerald ash borer Purdue” for the most up-to-date information about this pest. Links are also available at our local Extension office website at www.extension.purdue.edu/allen.
