Clover Mites

Clover mite
(Photo: Rayanne Lehman, PA Dept. of Ag)

You may soon begin seeing tiny, bright red insects crawling around on the sunny sides of buildings, windowsills, retaining walls, etc. Most likely, the insects are clover mites. They can become a problem in early spring when they invade structures in large numbers. Clover mites are tiny (1/30-inch long), red to reddish-brown, oval-shaped mites. Clover mites, as do other arachnids, have 8 legs. They hold the front pair of legs straight out in front of the head (see photo at left). Many people actually mistake this pair of legs for antennae.

Clover mites do not bite nor do they burrow under the skin. They are strictly plant feeders. Hosts include grasses, clover, and dandelion, to name a few. Most heavy outbreaks occur in the early spring, especially around heavily fertilized lawns. In heavy infestations, the mites may invade structures and can leave a reddish-brown stain if crushed.

Placing gravel around the structure can 

help prevent clover mite invasions.   

(Photo: M. Waldvogel, NCSU)

Control. Effective control means preventing entry into buildings in the spring. Exterior cracks around doors and windows or holes in the foundation should be caulked. An 18”-24” grass and weed-free zone around the structure’s perimeter can greatly reduce the number of invading clover mites (see photo at right). Many plants are actually unattractive to clover mites, including geranium, marigold, zinnia, salvia, rose, chrysanthemum petunia, juniper, spruce, yew and barberry. Planting these non-attractive plants in the weed-free zone will help reduce the number of clover mites around the structure. You may also contact your county Cooperative Extension Center for advice on proper fertilization of lawns. For extremely heavy infestations, it may help to treat a 5-10 foot wide area of ground along the foundation, as well as an 18-24 inch wide vertical band of the foundation wall with an appropriately labeled residual liquid insecticide. Keep in mind that you will be applying a broadcast spray in this case, so you must follow proper notification procedures.

 

The application of insecticides indoor for clover mites is not warranted. There is no specific target site and excessive indoor applications are potentially harmful to children, teachers, and staff. Clover mites are not a true “emergency” and so any spraying indoors would require that you follow the 72 hour notification policy. Simply use a vacuum cleaner to collect any mites found indoors. Care should be taken not to crush the mites. The vacuum bag should be sealed in a disposable plastic bag before throwing it away. 

Sugarcane Beetles

Adult sugarcane beetle (Photo: Cotinis, BugGuide.net)

We recently got a call from a NC school reporting that several buildings were being invaded by small black beetles. The insects, as it turns out, were sugarcane beetles (Euetheola humilis), a type of scarab beetle that can become a problem in the fall as it searches for a suitable place to spend the winter. The beetles are common insects, but their populations are usually so low that they go largely unnoticed. Sugarcane beetles can actually damage caulk or other sealants at expansion joints and other junctures as they attempt to dig into the area.


One thing to keep in mind about sugarcane beetles is that they are occasional pests that are normally present at relatively low levels. The beetles are attracted to light, so using sodium vapor lights in fixtures near buildings and mercury vapor lights for fixtures away from buildings can reduce the number of invading beetles; however, this may not be practical in school settings.

Sugarcane beetles gathering around expansion joint (Photo: Chris Mills, Union Co. Schools)

Insecticides are not very useful in controlling sugarcane beetles. The beetles may be sprayed directly in order to kill them, but the residual may not be sufficient to kill beetles that show up later. Any invading beetles should simply be vacuumed or swept up. In addition, replacing caulk that is damaged or missing should help decrease numbers of invading beetles.


For more information on sugarcane beetles, please see: http://msucares.com/newsletters/pests/bugwise/2009/bw0209.pdf

Brown Marmorated Stink Bugs are Causing a Stink!

Adult brown marmorated stink bug (Photo: Susan Ellis)

We have been getting a lot of reports of structures being inundated with what is likely the brown marmorated stink bug. This insect is a pest of a wide variety of agricultural and horticultural crops including soybeans, fruits, and ornamentals. During the fall, as things begin to cool down, adult stink bugs begin to search for a place to overwinter. Unfortunately, if school grounds are located near agricultural crops or orchards, or have  extensive plantings of ornamental trees, you may begin to see large numbers of this bug trying to invade buildings. Although their presence may be alarming to some, the stink bugs are not harmful. However, they do put off an unpleasant odor (they don’t call them stink bugs for nothing!).

This situation is virtually identical to the problems many of you have seen with boxelder bugs and the Asian lady beetles in that little can be done to stop them. With the upcoming frosts, particularly in western NC, we're likely to see the annual movement of lady bugs indoors by the time you’re reading this. It will progress in the Piedmont and eastern parts of the start likely towards the end of October.

Pesticide applications to the exterior of school buildings won’t have any real impact on the brown marmorated stink bug. In order to be effective, pesticides must be sprayed directly on the bugs or the bugs must land on a treated surface. If you decided the problem warrants an outdoor pesticide application, limit your treatment to exterior windows and doors, or other openings stink bugs are using to enter the building.

Spraying indoors for stink bugs won’t work because they show up in different places. There is no specific target site and excessive indoor applications are potentially harmful to children, teachers, and staff. Stink bugs are not a true “emergency” and so any spraying indoors would require that you follow the 72 hour notification policy.  Your best option is to use a vacuum cleaner to collect any invading stink bugs. They will stink up a shop-vac or regular vacuum cleaner fast, so use a “Knee-High” or part of panty hose inside the nozzle to collect the stink bugs and then discard it.  If you rely on just a vacuum cleaner bag, be sure to seal the bag inside a trash bag before disposing of it to keep the bugs from escaping.

This problem is relatively new for us but has been occurring north of

our border for some time and we expect it to spread to other counties over timeFor more information on the brown marmorated stink bug, please read NCSU’s publication which can be found at:

http://insects.ncsu.edu/O&T/trees/note148/note148.html