“WHAT’S HAPPENING?”

The University of Tennessee Extension Service

Entomology & Plant Pathology - EPP #60

September 9, 2005

LADY BEETLE REMINDER - “THE GAME IS WON OR LOST IN LATE SEPTEMBER/EARLY OCTOBER”

by Karen M. Vail

Predicting the Day of the Invasion

According to predictions by Ohio State University (OSU) IPM Program personnel, Multicolored Asian Lady Beetles (MALB) start searching for overwintering sites, your home, on the first or second day when temperatures are greater the 65E̊F after a dramatic drop in temperature, usually to near freezing. The MALB invasion started on October 6, 2004 in Minnesota. In Knoxville, the peak flight occurred around October 20 or 21, 2004.

Vertical Contrast and Not House Color Influence Attractiveness of Homes to MALB

Research from North Carolina revealed that it is vertical contrast, such as black shutters against light colored walls, shadows cast by a chimney, white shutters against a dark background, that is attractive to beetles. Color of the house will not matter in attractiveness to the beetle. After all, they are looking for a crack in a white/light-colored cliff or rock outcropping.

Management

Conduct Steps 1 and 2 by late September/early October , before MALB start their invasion.

1. Pest-Proof: seal entry points, keep window screens intact, screen vent openings, etc., before the beetles arrive. (See our UT Extension Service SP 503C Lady Beetles Invading Homes [http://www.utextension.utk.edu/publications/spfiles/sp503c.pdf ] for more specific recommendations on sealing entry points.)

2. Treat roof lines or soffits, vertical contrast areas, and entry points (around the following outdoor items: windows, doors, vents, pipe penetrations) with pesticides before the beetles arrive. According to Ohio State University results, professionals products such as Demand CS (lambda-cyhalothrin), Suspend (deltamethrin) or Talstar (bifenthrin) provided 96, 95, and 84% effectiveness at 3 weeks post-treatment, respectively, when applied to vinyl siding. Products available to homeowners, such as Terro Ant Killer (0.2% permethrin w/PBO) and Bayer Advanced Home (0.1% cyfluthrin) provided 96 and 92% effectiveness at 3 weeks post-treatment. Retreatment in 3 weeks may be necessary, especially if beetles have not invaded yet and if rain has been common.

3. Remove dead beetles as they pile up because they may cause other MALB to aggregate.

4. If the beetles make their way into the home, vacuum or try a light trap (see description below). Insert a knee-high nylon stocking into the extension hose or wand of a vacuum or dry vac and secure the stocking with a rubber band (see http://ohioline.osu.edu/hse-fact/1030.html). When the vacuum is turned off, remove the stocking so the rubber band will close around it, thus catching the lady beetles. You can then discard the contents of the stocking. Use a vacuum with a HEPA filter to prevent allergens from becoming airborne.

Refrain from using foggers indoors because they will not kill the majority of lady beetles which are hidden, they increase your exposure to insecticides unnecessarily and could supply dermestid beetles (carpet beetles, larder beetles) and other scavengers with food.

Trap Updates from OSU. A commercial black light trap caught 90% of the lady beetles released into an OSU study room. The manufacturer, Southeastern Insectaries, (877-967-6777 or 478-988-9412, sei@alltel.com) has upgraded this indoor light trap (BL) and suggests it is most effective when it doesn’t compete with sunlight and, to a lesser degree, other light sources. Thus, it is best operated during the night with no or limited competing light sources or in dark spaces such as attics or crawl spaces. These traps are mobile and should be moved to the rooms with the most beetle activity. If the beetles can’t see the light, it won’t work. Cost of this light trap is about $140.

The Ohio State University IPM Staff developed an inexpensive trapping device for use in homes. In their tests, the homemade trap caught about 70% of the released beetles in a room. During a presentation, Dr. Joe Kovach, OSU, mentioned that an incandescent bulb worked as well as a black light tube, but a black light incandescent bulb was not very effective. The homemade trap worked better if the funnel and collecting container (both plastic milk jugs) were painted black and dusted with talc. Descriptions of both light traps listed above can be found at http://ipm.osu.edu/lady/Lighttraps.htm .

While camphor and menthol may be repellent to lady beetles, more research is needed to make the formulation last longer.

Sources:

Jones, S.C. and J. Boggs. 2001. HSE-1030-01 Multicolored Asian Lady Beetle. Ohio State University Extension. http://ohioline.osu.edu/hse-fact/1030.html

The Ohio State University Web Site, Multicolored Asian Lady Beetle

http://ipm.osu.edu/lady/lady.htm

Vail, K. 2004. Lady Beetle Update Spring 2004 - “The Game Is Won or Lost in October”. In “What’s Happening?” University of Tennessee Extension, Entomology & Plant Pathology - EPP #60, Volume No. 1 - March 5, 2004. http://web.utk.edu/~extepp/whats/wh2004/Volume-1-04

DOWNY MILDEW OF CUCURBITS

by Steve Bost

Downy mildew has become widespread on cucurbits throughout the state. Try to catch the disease in the early stages, which appear as lime-green to yellow leafspots, turning necrotic. The lesions are tiny, about 1/16 inch, on pumpkin and squash leaves, but may be up to ½ inch on cantaloupe and cucumber leaves. Hopefully, growers have been using a basic fungicide such as chlorothalonil or mancozeb so that the first spore shower of downy mildew to hit the field doesn't hit so hard. When downy mildew does appear, add a more specialized fungicide such as Acrobat or Tanos to the basic fungicide. Another option is to substitute Cabrio, Pristine, Gavel, or Ridomil Gold Bravo for the tank mix. Whatever the fungicide choice is, two of them must be chosen. That is because any of these specialized fungicides needs to be rotated with another one that is not related to it. It is okay to apply chlorothalonil or mancozeb continuously, but not so for the specialized fungicides. There are many downy mildew fungicides on the market now; choose two that you like. Others that are not mentioned above are provided in UTAES PB1282.

In dealing with a cucurbit downy mildew outbreak, remember this: Although it needs moisture for infection, rainfall is not needed. If spores are present when a heavy dew forms, one night (8 hours, at typical temperatures) is all that is needed for infection. Also remember that, unlike most downy mildew species, high temperatures do not inhibit cucurbit downy mildew. It can proliferate in the heat of mid-summer.

CUCURBIT POWDERY MILDEW REMINDER

by Steve Bost

Remember that we no longer recommend the strobilurins (Quadris, Flint, Cabrio, Pristine) for control of cucurbit powdery mildew because of the prevalence of resistant strains. During powdery mildew season (now), use Nova, Procure, or sulfur in a tank mix with a basic fungicide such as mancozeb or chlorothalonil. Since resistance to the sterol inhibitors (Nova, Procure) is also a threat, you should rotate occasionally to sulfur. Remember that sulfur is strictly a surface protectant and coverage of both sides of the leaves is needed for good control.

FIRST 2005 HUMAN CASES OF WEST NILE VIRUS (WNV) CONFIRMED IN TENNESSEE

by Karen M. Vail and Reid Gerhardt

Three human West Nile virus cases, one female and two males, have been confirmed in Shelby County and all three are expected to recover. People contract the virus when bitten by an infected mosquito. While it is encouraging that the first cases occurred three weeks later than in the last two years, onset of the virus has been reported through October in the past. WNV-positive groups of mosquitoes have been recorded from two counties, Shelby and Davidson; however, only one group (0.2%) was found positive from Davidson while 320 (26%) Shelby County groups of mosquitoes were positive for WNV. As of September 8, birds have tested positive in Hamilton, Knox, and Robertson Counties. Therefore, to prevent other human cases we should emphasize protection from mosquito bites through the end of the mosquito season which could be as late as November.

To reduce the risk of a mosquito bite:

• Wear mosquito repellent containing products such as DEET, picaridin or oil of lemon eucalyptus when venturing outdoors. Read the repellent label and remember most repellents only last a few hours and must be reapplied.

• Wear long-sleeve shirts, long pants and socks when outdoors.

• Avoid outdoor activities at dawn and dusk when many mosquitoes are the most active or follow the above precautions.

• Remove standing water where mosquito larvae can live. See SP503B Mosquito Control Around the Home (http://www.utextension.utk.edu/publications/pests/default.asp) for a list of potential larval sites.

Sources

Turner, A.E. 2005. First Human West Nile Virus Cases of 2005 Confirmed:
Three Tennesseans Test Positive. Tennessee Department of Health September 2 Press release http://www2.state.tn.us/health/Newsreleases/90205a.htm

Tennessee Department of Health’s West Nile Virus Report Web Page, http://www2.state.tn.us/health/Ceds/WNV/wnv_report.asp

Tennessee Department of Health’s West Nile Virus Web Site,

http://www2.state.tn.us/health/Ceds/WNV/wnvhome.asp

Vail, K., K. Gottfried and R. Gerhardt. 1998. SP503B Mosquito Control Around the Home. UT Extension, http://www.utextension.utk.edu/publications/pests/default.asp

Disclaimer Statement

Pesticides recommended in this publication were registered for the prescribed uses when printed. Pesticide regulations

are continuously reviewed. Should registration or a recommended pesticide be canceled, it would

no longer be recommended by the University of Tennessee.

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.

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 mix, apply store or dispose of a pesticide. According to laws regulating pesticides, they must be used only as directed by the label.

Persons who do not obey the law will be subject to penalties.

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