| Dedicated to McDonough County Voice, USA TODAY NETWORK
GALESBURG – When it comes to invasive insects, a lot of our attention is focused on those that cause great damage, such as: B. Japanese beetles and emerald green ash cutters. However, there are a few other invasive insects in Illinois that you should be aware of.
Asiatic tiger mosquito (Aedes albopictus)
Asian tiger mosquitoes were first discovered in 1985 in Texas, USA, and have spread to more than 20 states, including Illinois. It is believed that it was introduced into the United States in rainwater in tires and that way spread across the country.
They get their name because of their white and black color pattern. Adults have black and white ribbons on their legs and a white stripe down the center of their head.
Asian tiger mosquitoes feed during the day. They are often found in shady areas where they rest on foliage near the ground. While they may not have particularly painful bites, they are persistent.
In addition to their pesky bites, these insects can carry and transmit Zika, dengue, or chikungunya viruses. However, they are nowhere near as effective carriers of these diseases as some other mosquito species and are not a problem in Illinois right now.
Women lay eggs on the sides of water containers like hoops, bird baths, and tree holes. The eggs hatch when covered in water, usually due to rain. The mosquitoes don’t fly very far. Eliminating habitats for oviposition (they can develop in just one cup of water) therefore goes a long way in reducing populations. Wearing shoes, socks, long pants, and long sleeved shirts can help prevent bites. Additionally, using insect repellants that contain DEET, picaridin, or lemongrass oil can help prevent bites from Asian tigers and other mosquitos.
Spotted wing Drosophila (Drosophila suzukii)
Spotted Wing Drosophila (SWD) was first found in the continental US in California in 2008. Since then, it has spread across the country, including Illinois, in 2012. It was likely spread in infected fruits.
Most fruit flies lay their eggs in fruits that are already ripe or overripe. On the other hand, SWD lays its eggs in ripening fruits just before harvest. When the small, white, and cylindrical larvae of the brood hatch in the fruit, they begin to feed, and the fruit begins to collapse in just two days. Once this happens, fungi can enter and further decompose the fruit.
SWD is primarily a pest of fruits such as strawberries, raspberries, and blueberries. They also attack fruits like cherries, peaches, grapes, and tomatoes. It will also feed on “alternative” hosts such as elderberry, pokeweed, and dogwood. If you grow any of these fruits, you can build a trap to monitor them.
SWD are small (1/8 inch) flies with red eyes, a brown rib cage, and black stripes on the belly, similar to many other species of fruit flies. To distinguish SWD from other fruit flies, you can look at the wings of the males. Male SWDs have a dark spot on their wings near the wing tip. Female SWDs are a little harder to identify (they don’t have wing spots), but they have a fairly large ovipositor (structure for laying eggs) with jagged edges. These gears allow the females to lay eggs in unripe fruit.
Viburnum leaf beetle (Pyrrhalta viburni)
The viburnum leaf beetle (VLB) is native to Europe and was found in North America in Canada in 1947. It was first found in 1996 in the USA in New York. It was first found in Illinois in the Chicago area in 2009.
Both the adults and the larvae feed on viburnum leaves. The larvae often feed in groups and make the leaves look like spikes (like Japanese beetles). The adults create elongated holes in the leaves. When the beetle populations are high enough, they can defoliate plants, which over time weakens them and can eventually lead to death.
The larvae hatch in May and are yellowish-green in color. They have black spots and lines on their bodies. They feed for about a month and begin to pupate in the ground in early to mid-June. Adults are about ¼ inch long and golden brown and will appear in mid to late July. In summer and autumn, the females chew pits in twigs, lay eggs, and then cover the eggs with chewed pieces of wood. Females can lay up to 500 eggs in their lifetime, and those eggs hatch the following spring. Adults are active until the first frost.
Viburnum species differ in their susceptibility to attack by VLB. Some species such as arrowwood (V. dentatum) and American cranberrybush (V. opulus var. Americana) viburnum are very vulnerable and can be killed in as little as 2-3 years. In contrast, some species such as Koreanspice (V. carlesii) and Judd (Viburnum x juddii) are viburnum resistant.
If you plan to plant viburnum and live in an area with VLB, avoid planting susceptible varieties. If you have viburnum, examine your plants between fall and spring for branches with eggs. If you find any, prune them and destroy them. Chemicals can also be used to manage the beetles.
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