What's Happening 8/25/2006

“WHAT’S HAPPENING?”

The University of Tennessee/Agricultural Extension Service

Entomology & Plant Pathology - EPP #60

August 25, 2006

Velvet Ants - Large, Fuzzy, Red/Orange and Black Wasps

Karen M. Vail

We’ve been receiving calls about large, fuzzy “ants” for few weeks now and even had a report of a velvet ant in an attic, but we are waiting to receive a specimen to confirm that identification. Often folks are concerned that these are fire ants and are amazed when I explain that velvet ants are wingless wasps. Most are also amazed that they are found in Tennessee because they have not seen them in the 30 or more years they have resided here.

Useful questions and answers that will help identify the mystery “ant” as a velvet ant are listed below:

1. Q: Does it resemble an ant? A: Yes.

2. Q: Is the insect hairy or velvety? A: Yes.

3. Q: Does the insect have a bump on the waist? A: No.

4. Q: Is it orange or red with black stripes on the abdomen? A: Yes.

5. Q: Is it difficult to crush? A: Yes.

6. Q: Does it produce a rasping sound when stepped on? A: Yes.

7. Q: Are there many of these ants in a trail? A. No.

The velvet ant’s common name is a misnomer. They are actually more closely related to wasps than ants and are often called wingless wasps. The wingless females resemble an ant, but lacks a node or bump on the waist. Males, on the other hand, do have wings and actively fly. These ants are orange or red and often have black stripes toward the back of the abdomen. A dense coating of velvety hair covers this insect. An image of Tennessee velvet ants can be found at http://web.utk.edu/~extepp/profiles/insects/velvetant.htm.

Biology. Velvet ants are solitary wasps. Larvae, the immature feeding stage, feed externally on the prepupal or pupal stages of ground-nesting bees, other wasps and some flies and beetles. Females actively search for hosts on which to deposit eggs. The host is attacked after the cocoon has been spun or the fly puparium formed. Upon locating a host, the female uses its long ovipositor (which can also function as the stinger) to penetrate the cocoon or puparium and deposits one or two eggs. Eggs hatch and larvae feed on the host, devouring it. After feeding, the larval velvet ant spins its own cocoon inside that of its host. Overwintering occurs as the prepupal stage inside the host's cocoon.

Upon emerging as adults, winged males search for mates. The male is attracted by a specific sound produced by a rasping structure located between their second and third abdominal segments of the female. The rasping sound also occurs when the wasp is pressed or attempted to be crushed. Mating usually lasts just a few seconds. Males may also be seen visiting flowers in search of nectar.

Importance. Females spend much time in sandy areas searching for hosts and may be encountered by adults and children. The females can sting repeatedly. The stinger is long and produces quite a painful sting – perhaps the reason that the large common species is called the"cow killer". People are most often stung by velvet ants while walking in infested areas without proper footwear. The intensity of pain and allergic reaction to the sting will vary according to the immune response of the person stung. These are solitary creatures and the possibility of being stung by a number of these insects at one time is unlikely. Ground-dwelling bees, which may be important pollinators of some crops, are known to be hosts for velvet ants. Other species are reportedly pests of white grub parasites, a condition known as hyperparasitism. Therefore, velvet ants can be considered either beneficial or pestiferous depending upon the host species attacked.

Control Measures. Chemical control of velvet ants is rarely needed. The best methods for dealing with velvet ants are: 1) to inform people, especially children, not to handle these insects and 2) to wear shoes in infested areas to avoid accidental encounters. On occasion, the numbers of velvet ants in an area such as gardens or underneath houses, trailers or other raised structures may be high enough to warrant control. In these cases, the best control tactic would be to eliminate ground-nesting wasps or bees on which immature velvet ants feed. Although the exoskeleton seems uncrushable, individual velvet ants can be killed by crushing. Household aerosol formulations labeled for wasp control can also be directed at the velvet ant.

If you are still unsure of the “ant’s” identification, more information on ant, including fire ant, identification and management, can be found in our new fire ant web site at: Imported Fire Ants in Tennessee http://fireants.utk.edu.

Modified from: Drees, B. 1988. VELVET ANTS. UC-001 Texas Agricultural Extension Service.

NEW Product may be available for mosquito control in late 2006

by Darrell Hensley

Cognis Corp. has been granted approval by the U.S. Environmental Protection Agency (EPA) for a new granular formulation of its liquid mosquito control product, Agnique MMF G (monomolecular film). This product offers outstanding biodegradability, is an effective, non-toxic weapon in the fight against mosquitoes.

The principle is quite simple. Sprayed either manually or from a helicopter, the agent spreads as a monomolecular, extremely thin, film on the water surface. It reduces the tension at the interface between air and water, thus preventing the mosquito larvae or midge grubs from “docking” at the surface in order to take in air. Seen from the opposite perspective, fully grown mosquitos have no chance of relaxing or laying eggs when they land on the water. The reduced surface tension ensures that they quickly sink.

Cognis received FDA approval in the USA for this innovation in 2000, a certificate that enjoys the highest recognition around the world. The product is also EPA-approved. Agnique® MMF is insoluble in water, and has no effect on the dissolved oxygen, pH or fluidity of the water. It is not toxic to fish, does not pollute the surrounding vegetation, and it contains no aromatic compounds. There is no method on the market of combating mosquitoes over wide areas that is more environmentally compatible. Agnique® MMF is available both as a consumer product for the home and gardening sector and for professional use in all mosquito breeding habitats. There are several benefits to the product which include; Non-toxic to most non-targeted wildlife, controls both larvae and pupae, effective in all stages of the mosquito life cycle, cost reduction because of low dosage and excellent spreadability, not visible on water surface, may be applied by conventional spray methods, has a long shelf life of over two years, no premixing, it is biodegradable. To find out more visit: http://www.mosquitommf.com. The product is being submitted for state registrations and should be available in late summer or early fall 2006. Source: Pest Control Buzz Online Newsletter.

Foreign Grain Beetle Adults, Pests in Newly-Constructed Homes, Are Active!

Karen M. Vail

We received a few calls about or specimens of foreign grain beetles. Foreign grain beetles are small (1/12 inch), reddish-brown beetles that feed on molds and fungi. Foreign grain beetles look very similar to red or confused flour beetles, hairy fungus beetles or sawtoothed grain beetles, but can be distinguished from these species by the presence of a projecting rounded lobe on the front corners of the pronotum. An image of the beetle can be found at EPP 654 - Foreign Grain Beetle Invades Homes http://web.utk.edu/~extepp/pubs/frgrnhtml99.pdf. Other pests of mold, such as minute brown scavenger beetles, have also been brought in for identification. With the heavy rains we have been experiencing, I expect will see more of these insects that feed on molds and I would expect next year’s “crop” of foreign grain beetles to be more numerous than usual.

Because there are so many similar species, it is best to seek identification from an expert. Your county Extension Agent should be your first stop. See the blue pages in the phone book or The University of Tennessee Personnel Directory Web Site (http://www.agriculture.utk.edu/personnel/districts_counties/default.asp) to find your local county Extension office. If the agent is unable to identify the insect, they can either mail it to the UT Extension Service Plant and Pest Diagnostic Center in Nashville or if they are one of 58 counties with distance diagnostic equipment (http://web.utk.edu/%7Eextepp/ddtrain/equipped-counties-web.jpg), they can upload a digital image of the suspect specimen through the Distance Diagnosis Web Site http://web.utk.edu/%7Eextepp/diagnost.htm. It is important that at least one magnified image of the pronotum’s (“shoulder’s”) front corners be included in the submission.

Foreign grain beetles may appear in newly-constructed homes by the thousands. Typically, the female is attracted to poorly-seasoned lumber or wet plaster and wall board that supports fungal growth. Foreign grain beetles can also be associated with plumbing leaks, condensation problems, or poor ventilation. Eggs are laid on these materials as the house is being built and larvae feed on the molds. In the late summer, adults become obvious when they emerge from the wall voids and are attracted to lights.

To control these beetles, wet wood and the moisture source should be eliminated. Adding ventilation such as air conditioners, dehumidifiers and fans may be needed to remove the moisture. Often, homes will dry out naturally in 1-4 years thereby eliminating the fungal food source and hence the beetles. Pyrethrin sprays can kill the adults, but need to be applied frequently as the beetles continue to emerge from wall voids. Vacuum cleaners work just as well as sprays to remove any visible beetles that are present. Pest control companies may be able to provide additional relief by locating the infested wall areas or source of dampness by using a moisture meter or by inspecting areas where the beetles are most abundant. A residual aerosol or dust can then be injected into cracks and crevices along baseboards and into the wall voids. This may provide some relief; however, the beetles may still emerge from the baseboards and die on the floor.

If the homeowner can tolerate the beetles during the period when they are most active (late summer) the problem may resolve itself. Remember, foreign grain beetles are a nuisance by their mere presence, they do not bite or damage wood, fabric or stored food in sound condition.

Modified from: Potter, M. 1997. FOREIGN GRAIN BEETLE. University of Kentucky, College of Agriculture, Cooperative Extension Service. http://www.uky.edu/Agriculture/Entomology/entfacts/struct/ef610.htm

Small Fruit Flies

Karen M. Vail

During the hot summer, when vegetables harvested from the garden are piling up on the counter and fruit ripens very quickly, small fruit flies often become a nuisance. Small fruit flies in the genus Drosophila are about 3 mm or 1/8-inch long, have a yellow to light brown thorax, a yellow abdomen with black stripes and the most striking characteristic is the red eyes. Most entomologists will use the wing venation to confirm identification.

As with most flies, locating and removing larval food sources is the only way to eliminate an infestation. Repeated applications of fast-acting insecticides will knockdown the adult population, but the problem will continue as new adults emerge. Until larval sites are removed or cleaned, the problem will continue.

Biology

Eggs are laid near fermenting foods and other moist, organic materials. Favorite oviposition sites include melons (cantaloupe, watermelon) squash, tomatoes, grapes and other vegetable matter brought in from the garden as well as over-ripe or rotting bananas, potatoes, onions and other produce that had been purchased at the grocery store. Additional larval sites included dirty mops and cleaning cloths, “empty” bottle and cans in recycle bins, garbage cans and under the liner in garbage cans, and in-sink trash disposals. Less often, they can be found in drains, and some species may be found in human, chicken and pig feces.

Upon hatching larvae will surface feed on these fermenting products. Because they don’t burrow deep into the material, infested parts of the vegetable or fruit can be trimmed potentially leaving the remainder free of the larvae. Time to develop from egg to adult varies, but can be completed in about eight to ten days. One female can lay about 500 eggs in her 40 to 50 day life span.

Prevention - Eliminate attractive food sources.

Control

Find and remove larval sites described above. For areas that can’t be inspected such as garbage disposals or drains, try covering them with a clear plastic bag and tape down the sides to seal it against the surface. If flies are present, they will be caught in the bag.

The flies will often be found in more than one site, so such the entire structure for all potential fly food sources.

Once the larval sites have been eliminated, the structure can be rid of adult flies by using traps or spraying aerosols. Commercial fruit fly traps are available, but most folks can make an inexpensive and effective trap from materials found around the home (Figure 1). Make a paper funnel, i.e., roll a sheet of notebook paper, place it into a jar and bait the jar by adding a banana slice or a few ounces of cider or other vinegar. Place these traps where the fruit flies have been seen and soon the remaining adult flies will be caught.

Note: Several species of fruit flies besides our most common, D. melanogaster, are becoming more common as pests in commercial facilities. D. repleta and D. hydei are darker species of fruit flies, have dark red eyes, have narrower yellow bands on the abdomen and are slightly larger (3.5mm) than D. melanogaster (3mm), and have hairs or bristles on the middle section of the thorax that arise from dark spots which give the thorax a speckled or freckled appearance. D. repleta or the black fruit fly larvae feed on fungi, mold, yeast or bacteria on decaying matter and are a problem in confined poultry and swine production. D. hydei larvae prefer organic matter found in drains and sewers and are becoming more common in commercial food accounts.

Sources: Potter, M. 2006. Fruit Flies. Kentucky Pest News. No. 1105, August 14. University of Kentucky Cooperative Extension Service. http://www.uky.edu/Agriculture/kpn/kpnhome.htm.

Potter, M. 1994. Fruit Flies. Ent-Fact 621. University of Kentucky Cooperative Extension Service. http://www.uky.edu/Ag/Entomology/entfacts/struct/ef621.htm.

Anonymous. Small Fruit Flies. Whitmire Prescription Treatment Brand Pest Management Bulletin. Vol. 7. http://www.wmmg.com/pdf/pmb/bulletin_vol7.pdf.

Hedges, S. 1995. PCT Field Guide for the Management of Structure-infesting Flies. Franzak and Foster, 151 pp.

Figure 1. Fruit fly jars traps. From left to right, an old-timey glass trap; a new, inexpensive trap; and a homemade trap.

OTHER UT NEWSLETTERS WITH PEST MANAGEMENT INFORMATION

Fruit Pest News

http://web.utk.edu/~extepp/fpn/fpn.htm

Tennessee Crop and Pest Management Newsletter

http://www.utextension.utk.edu/fieldCrops/cotton/cotton_insects/ipmnewsletters.htm

This and other "What's Happening" issues can be found at http://web.utk.edu/~extepp/whatshap.htm

Precautionary Statement

To protect people and the environment, pesticides should be used safely. This is everyone’s responsibility, especially the user. Read and follow label directions carefully before you buy, mix, apply, store or dispose of a pesticide. According to laws regulating pesticides, they must be used only as directed by the label.

Disclaimer

This publication contains pesticide recommendations that are subject to change at any time. The recommendations in this publication are provided only as a guide. It is always the pesticide applicator's responsibility, by law, to read and follow all current label directions for the specific pesticide being used. The label always takes precedence over the recommendations found in this publication.

Use of trade or brand names in this publication is for clarity and information; it does not imply approval of the product to the exclusion of others that may be of similar, suitable composition, nor does it guarantee or warrant the standard of the product. The author(s), the University of Tennessee Institute of Agriculture and University of Tennessee Extension assume no liability resulting from the use of these recommendations.

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