Monday, March 17, 2014

Ground Bees Active But Pose No Threaten to People or Yards, by Steve Frank, NCSU Extension Entomologist

As I write this my front yard is abuzz with small bees. Many are flying around just above the ground while others fly back and forth to redbuds and camellias gathering pollen.

Although these bees do not generally sting, I watch as mothers nervously cross the street with strollers. Neighbors pass by and comment "Watch out for all those fire ants" referring to the small mounds that dot my sparsely vegetated lawn. Others offer suggestions on how to rid myself of these dangerous beasts that are "tearing up your lawn."

The bees I am watching are ground nesting bees in the family Andrenidae. All the species in this family are solitary and nest in the ground. Solitary means they do not maintain vast hives with hundreds of workers like honeybees or yellow jackets. A single female bee builds the nest by burrowing into the ground. She prepares larval cells where eggs will be laid. Mothers provision each brood cell with a mixture of pollen and nectar (called bee bread) that serves as food for young larvae. After laying an egg she closes the brood cell and starts another. After completing several brood cells the mother will seal the entrance and leave the nest to begin a new nest. After a few weeks she will die leaving the next generation safe in the ground.

Bee emerging from its mound (Photo: S.D. Frank).

In the spring, bees complete development and emerge as adults that dig their way out of the ground and forage for pollen and nectar to provision their own nests (see photo above). The visual spectacle of these bees is produced largely by males who swarm over nests trying to mate with newly emerged females. The other noticeable aspect of these bees is the small mounds of dirt excavated for each nest.

Hundreds of small mounds created by bees.
Hundreds of small mounds and swarms of bees often trigger calls to exterminators or landscape professionals (see photo at right). Homeowners fear that they will be attacked and stung as they bend over to pick up the paper and they believe that the bees are actively damaging their yard and want them gone. This is not the case.

An ovipositor is the organ female insects use to insert eggs into substrates such as leaves, wood, soil, other insects, or in our case brood cells. In social insects such as honeybees, most of the females are workers that do not mate or lay eggs and thus have no need for an ovipositor. However, they do need to protect the nest from invaders. Therefore, the ovipositor of these social species has evolved into a stinger to ward off threats.

With this in mind it is easy to understand why the threat of being stung by the ground nesting bees in my yard is so small. First, the bees swarming around are mostly males. Males don't lay eggs and thus do not have an ovipositor, modified or otherwise. The female bees are responsible for all aspects of nest construction and provisioning and are busy digging and foraging. Since the ovipositor of ground nesting bees is necessary for laying eggs, it is not well developed as a stinger, if at all. I won't say that you will never be stung because this would encourage some fool to torment bees until they proved me wrong. However, I have handled these bees quite a bit and have never been stung (see photo below).

Bee held safely for a portrait (Photo: S.D. Frank).
These bees prefer to nest in dry, sparsely vegetating areas. Therefore, if you have bees nesting in your lawn it is because the grass is thin and the soil is dry. The bees don't make it this way, they just take advantage of the conditions. If anything the bees are providing a valuable service by aerating the lawn!

The behavior and habitat preference of these bees leads us to the most promising ways to reduce their abundance in a particular yard. First they like dry soil they can dig nests in. Therefore, irrigation over the 3-4 weeks bees are active will encourage them to find other nest sites and reduce their abundance the following year. In addition, they like thin lawns with plenty of bare spots. Thus, you can take measures to improve the density of your grass to make it less appealing to bees. Native bees are an important part of ecosystems and food production. We should take steps to protect these bees or at least use non-lethal means to encourage them to nest somewhere else.

Wednesday, March 5, 2014

Termites Swarming

We are already starting to get reports of termites swarming. Just last week, we had termites swarm in a building on NCSU campus. You may have already experienced some swarms in some of your buildings. Eastern subterranean termites generally swarm from late-February to May. Swarming usually occurs during the day, particularly on warm days following rain. Swarms occurring outdoors near tree stumps, landscape timbers, etc., are not an indication that a structure is infested, but simply serve as a reminder that termites live around us. However, when swarming occurs indoors, it usually means that there is an infestation somewhere in the building.

If you have an indoor swarm, simply suck up the swarmers in a vacuum cleaner. Place the vacuum bag inside a plastic bag and seal it before disposing of it. There is no real need to spray them; plus spraying in this situation would require notification. There is also no need to rush treating the building. This situation would not be considered an emergency. Plan the treatment for a teacher workday or holiday when that part of the building is or can be vacated. The treatment will vary depending on where the termites were found swarming. A spot treatment may be all that is needed and will not be as expensive as a full treatment of the structure.

Wednesday, February 5, 2014

New brochure on IPM for Schools and Child Care Facilities

A collaborative effort between NCSU, Texas A&M and Syngenta has produced this new IPM publication - "An Ounce of Prevention!" covering IPM for Schools and Child Care Facilities. 


Monday, November 4, 2013

Proper Use and Maintenance of Insect Light Traps

If maintained and used properly, insect light traps (ILTs) can be very effective at both capturing and monitoring for flies. ILTs allow for easy identification, because generally, intact flies are preserved in the sticky traps. The following maintenance and use tips will help ensure your ILTs are working to the best of their ability:

Light Trap Location. Location and proper positioning are main factors in successful light trap usage: 

Install light traps on the same wall as entryways, 
if possible (Photo: Mike Waldvogel, NCSU)
  • Install traps either on the same wall as the entryway (see photo at left), or on a nearby perpendicular wall. The attractant light should not be seen from the outside to avoid attracting outdoor flies.
  • Avoid other light sources that could potentially compete with the trap. Try to avoid placing ILTs in brightly lit areas, if possible.
  • Insects need to be able to see the light, so make sure that there is nothing placed in front of the ILT that would substantially block the light.
  • For day-flying insects like house flies, install wall-mount or corner-mount light traps low.
  • Ceiling-hung traps work better for night fliers like stored product moths.
  • Install ILTs along the path to stored or processed food. Narrow hallways are good installation sites. ILTs are most effective where flying insects are funneled into narrow spaces.
  • In food-processing areas, place ILTs so as to draw insects away from the food. Do not install ILTs over exposed food or near food prep surfaces.
  • Place open tube electrocuting traps near back doors that lead to garbage areas and dumpsters but are not near food or customers. 
  • To capture Drosophila (fruit flies), place an ILT that contains a sticky board low behind counters or behind beverage or salad bars.
  • Place ILTs in drop ceilings or attics to trap overwintering flies, such as cluster flies.
  • Don’t place ILTs near air blowers or in areas where there are strong air currents. 

Light Trap Maintenance. Be sure to dust off the lamps and the guard door on a regular basis. Use a wire brush to remove insects from the grid. The lamps, reflector and grid should be periodically washed with warm, soapy water. Inspect the trap for signs of electrical problems like damaged wires, cracked insulators, scorched transformers or loose electrical connections. Most ILTs will automatically turn off the electricity when the trap is opened for inspection or maintenance. However, it may be necessary to unplug the unit before cleaning.

Many ILTs use glue boards rather than a collection tray. Glue boards that are dusty or full of debris and insects will not be ineffective and should be changed. Even if the glue boards are clean and empty, they can dry out over time. Check the manufacturer’s recommendations for replacement of the glue board.

Most manufacturers recommend that lamps be replaced at least annually. The effective life of a lamp is about 7,000 hours or 9½ months of use. Even if the light appears alright, it may no longer attract insects. It’s good practice to replace the lamp in the spring to ensure they are most effective during peak season. 

Collection trays should be emptied and cleaned regularly. Dead insects left in the collection tray may attract dermestid beetles, so don’t wait until it’s full of insects to empty the tray. A small paint brush can be used to brush insect parts out of the catch tray and other parts of the trap. 

Examine the catch. Examine traps regularly. An increase in trap catch or the appearance of a new pest may indicate a developing pest problem somewhere in the building.

Use and promote IPM. Fly management will get an extra boost if other pest control strategies, such as exclusion and sanitation, are integrated with ILTs. Discuss with and educate your customers about the issues that may be contributing to a fly problem. Provide recommendations for minimizing these conditions. In addition, take advantage of any opportunities for some up-selling. For example, you might recommend the use of fly fans (air curtains) and/or vinyl strips at exterior doors and loading docks.

Tuesday, September 17, 2013

Kudzu Bugs on the Move Again

Kudzu bugs aggregating on structure searching for 
overwintering sites (Photo:  Dan Suiter, Univ. of Georgia)
Kudzu bugs will soon be moving out of soybean fields, which means you may begin seeing them aggregating on or inside structures, including homes and schools. The kudzu bug's fall movementindoors is very similar to what we've experienced since the 1990’s with the Asian lady beetle. The major difference between the two insects is that the Asian lady beetle is actually beneficial as a biological control agent because it feeds on aphids and other plant-feeding insects. By contrast, the kudzu bug's primary food source (aside from kudzu) happens to be field crops, such as soybeans, where they can significantly impact yield. The kudzu bugs fondness for soybeans is one reason why we could see significant numbers of them invading homes and other buildings, even in rural areas. In more urban areas, there are plenty of other hosts, such as wisteria and privet. The insects are quite mobile; they are able to catch rides on wind currents, as well as automobiles, trucks, trains, and planes. This helps explain why this pest has managed to spread in about 4 years from the north-central Georgia to most of South Carolina, North Carolina, and on into Virginia (plus west into Mississippi).

At this point, we still do not have anything new to report in terms of recommendations as to how to address this problem. Kudzu bugs are attracted to light-colored surfaces but that certainly doesn't mean that brick buildings or those with dark-colored siding will escape the bug invasion. While shortcuts and easy solutions would be nice, there simply aren't any.

The emphasis still has to be on exclusion because chemical control is only partially effective and relies primarily on targeting the insects that are aggregating on surfaces. Preventive sprays are not recommended because they simply won't be durable enough to last the weeks during which these insects will be actively seeking overwintering sites. If you feel a treatment is required, stick with targeted treatments of critical areas: windows and doorframes, soffits, and eaves. If you choose to treat using a pyrethroid insecticide, remember to follow new label requirements. For the latest label changes, visit:

For more information about the kudzu bug, please visit our website:

Friday, May 24, 2013

Cockroaches Quickly Lose Sweet Tooth To Survive

Thursday, April 11, 2013

Paper Wasps Showing Up

Paper wasps (Polistes sp.) are long-legged, reddish brown to black insects with slender spindle-shaped abdomens. They may have differing degrees of yellowish or brown striping. Paper wasps can become a problem in the fall as the inseminated queens invade homes in search of overwintering sites. But paper wasps can also become a problem in the spring. As temperatures begin to climb, queens that spent the winter in structures become active and fly about. If they have been resting in an attic, wall void or crawlspace, the wasps may be attracted to light coming through a gap in the baseboard or a wall fixture, or around an AC vent and emerge inside the building. Since there are no nests or young to defend, the only real danger of being stung is from accidentally stepping on or pressing against one.

Figure 1. Use an aerosol insecticide 
to destroy a paper wasp nest
(Photo: Patty Alder)
Control. Queens that are found indoors may simply be swatted or vacuumed. If a queen does manage to get outdoors and start a nest, a broom may be all that is needed to knock it down. If a wasp nest has had some time to grow and is considered to be a hazard, they are most easily destroyed in the evening with an aerosol insecticide that is labeled for "hornets or wasps" (see Figure 1). This type of treatment may be considered an emergency (especially if the nest is located in place likely to be encountered) which means application to the nest can be made as long as notification occurs within 72 hours of application.

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