In the US, the worst stink bug summer for farmers was 2010, however the summer of 2013 may also be a bad year. These Asian stink bugs probably came to the US inside imported Asian products sometime in the late 1990s because a short time later they were seen in Allentown, Pennsylvania, and since that time, they have also been seen in at least 39 other states.
During the cold months, they find warm places inside to live, but after the temperatures starts to rise, they go back outside and look for food and mates. It is this time that farmers dread the most, because the Asian stink bug will feed on over half a dozen different North American crops including peppers and peaches.
They get their name because of the pungent odor that results from them being squashed, but there are main two fears from this particular invader. One fear is of their insatiable appetite for vegetables and fruits, sucking out the juice and breaking down the flesh until there is very little left at all. The main crops the Asian stink bug enjoy include tomatoes, peaches, grapes, apples, soybeans and peppers, this is according to research entomologist Tracy Leskey who is leading a team of dedicated USDA people, who are trying to find ways to manage this problem. According to Leskey, the insects caused $37 million in 2010 of damages to just apple crops.
The Asian stink bug can be distinguished from the native American stink bug by a mottled appearance on the abdomen and white stripes on the antennae. Stink bugs that are native to the US also cause damage, however their population is too low to have much of an impact. The second fear is that the amount of insects that prey on the Asian stink bugs is not enough to keep up with their population, and this gives it nearly unchecked freedom to reproduce, eat and flourish. There are some solutions that Leskey and her team have been working on, but some farmers have resorted to using pesticides.
The farmers are not at all happy about having to use pesticides because many of their families partake on the fruits and vegetables they grow, so they are looking for both an economically feasible and environmentally safe solution. The Leskey team has found some things that attract stink bugs are white, black and blue light as well as certain pheromones. These pheromone lures have been successful on a small scale to draw the bugs into traps, but a method has not been devised to catch the stink bugs on a large scale.
It is clear that using pesticides for a long term solution is out of the question because of the danger to humans. The USDA’s stink bug management team’s Hoelmer, is working on ways to to contain the insects and is looking for “natural enemies” to help provide control. When none could be found in the US, they started looking toward the stink bugs natural enemy in Asia.
In flies the Trissolcus wasp.
The Trissolcus is a tiny, parasitic wasp that thrives in Asia from destroying the Asian stink bug, which is why they are not a problem in Asia, but are in the US. The way these tiny wasp control the stink bug population is when a female finds a cluster of stink bug eggs and lays her own eggs inside them. As the wasp larva begins to develop it will feed on the host stink bug eggs until there is nothing left to feed on. This method in the insect world is called the “balance of nature.”
All insects have a natural enemy that preys upon it and in this way, nature controls itself. Certainly, turning the tiny wasp loose in the US is a more cost effective and safer approach than using other methods like pesticides and once they are introduced they will spread and reproduce and not be a threat to humans at all. Extensive research has shown that the Trissolcus wasp are only a threat to stink bugs and their eggs and there is no possibility of them stinging humans or animals nor do they feed on plants. However, there is one possible downside and that is if the wasp go after the native North American stink bug or other insects.
Naturally, the scientist do not want to cause harm to species that are not the target so the Asian Trissolcus will continue to be studied in a Newark laboratory until it is determined they will not be a threat to anything other than the Asian stink bug. If the research goes well, the wasp will be let loose as soon as next year. As far as the farmers in the US go, it cannot be soon enough to save their crops and millions of dollars in revenue.