Month: August 2014

What type of spider is this and what is the risk?

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Brown widow spiders – hiding in a log near you

Stephanie Schupska, news editor with the University of Georgia Public Affairs Office

A brown widow spider will usually hide when it senses danger. In fact, a person is more likely to be hit by lightning than be bitten by a brown or black widow spider. Image credit: Nancy Hinkle.
A brown widow spider will usually hide when it senses danger. In fact, a person is more likely to be hit by lightning than be bitten by a brown or black widow spider. Image credit: Nancy Hinkle.
Glove up before clearing brush, cleaning out the garage or pulling logs off the woodpile this winter. A brown widow spider or her more commonly known sister, the black widow, may be hiding in the shadows.

The brown widow’s camouflage – an orange hourglass on a brown body – makes her hard to see. That’s good for her but bad for the person who sticks a hand too close to her web.

Avoids people

The brown widow usually tries to stay away from people, said Whitney Boozer, an entomology graduate student with the University of Georgia College of Agricultural and Environmental Sciences.

“If they’re disturbed, they drop off the web, curl up in a ball or retreat,” Boozer said.

They can’t retreat when they’re pressed up against someone’s skin, though. A brown widow gets in this situation when someone wraps a hand around her while she’s holed up some place.

Wear long sleeves and gloves

Gloves and long sleeves will protect you “if you’re working in areas where brown widow spiders are commonly found,” Boozer said. Outside, brown widows prefer woodpiles, tires, empty containers and eaves. Indoors, the spider prefers protected places like under furniture and in shoes.

Shake clothes and check shoes before putting them on if they are left outside or in a garage.

Bites by brown widows cause severe reactions in 5 percent of people who are bitten. The young and old are especially vulnerable. With medical intervention, bites are almost never fatal.

The only scientific data collected on deaths attributed to widow spiders was taken between 1950 and 1959. During that time, 63 people died from the spiders’ bites, said Nancy Hinkle, a CAES entomologist.

Indoor plumbing lowered bite numbers

“Doubtless those numbers are much lower now that we have indoor plumbing because most widow bites occurred in privies,” she said.

According to Boozer, the brown widow’s venom is more toxic than that of her black cousin, but she injects less venom when she bites.

“In my whole life, I have known only one person bitten by a widow spider, and actually I didn’t know him, he just called my office,” Hinkle said. “On the other hand, I have personally known three people who were struck by lightning.”

She estimates that there are fewer than seven people killed each year by widow spiders. More than 1,000 people each year are struck by lightning.

A bad reputation

“So your chance of being killed by a widow spider bite — even without treatment — is over 100 times less than your chance of being struck by lightning,” Hinkle said.

Despite the odds, brown widows still aren’t spiders most people want wandering around in their homes. If you do see one, don’t panic. Boozer suggests taking it outside or vacuuming it up.

“Even outside, you’re allowed to kill widow spiders,” Hinkle said, who usually cringes when the conversation turns to smashing spiders.

Crush the egg sack, too, Boozer said. A brown widow’s egg sack is sphere shaped with spindly spikes of webbing sticking up all over it.

If desperation leads to a chemical attack, it’s best to spray spiders directly, Boozer said. Spraying a home’s perimeter may prevent spiders from entering it, but it won’t kill the ones already there. Brown widow spiders avoid places that have been sprayed.

Fall Armyworms in Turf

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Will Hudson1, Cheri Abraham2 and Kris Braman1

1 UGA Entomologists and 2 Field Operations Manager/ Entomologist at US Citrus, LLC

Fall Armyworms in Turf
Large armyworm. Photo by Kris Braman, UGA Entomologist

In late summer, almost every year, caterpillars invade turfgrass throughout Georgia. The damage to established turf is mostly aesthetic, but newly sodded or sprigged areas can be more severely damaged or even killed. While there are several caterpillars that can damage turfgrass, in late summer most of the problems are from fall armyworms.

Hot, dry weather can intensify fall armyworm problems when egg-laying adults concentrate their eggs in irrigated, green turf.  At least some cultivars of all warm season grasses are susceptible.  Cool season grasses like tall fescue are very favorable for fall armyworm growth and development too, and do not regenerate as readily as the stoloniferous grasses.

Fall armyworm adults migrate northward every year from southern overwintering areas.  Adult armyworm moths are active at night and females lay eggs in masses of 50 to several hundred.  These night-flying moths are attracted to lights and to lighter colored surfaces.   Egg masses on structures around turf (eaves and gutters, fence and porch posts, flags on golf courses) and even on taller foliage plants can be the first indicators of incipient infestations.

Fall Armyworms in Turf
Small armyworms feeding on leaves. Photo by Kris Braman, UGA Entomologist

Eggs hatch in a few days, and the young larvae begin to feed on leaf tissue.  Damage from small larvae may at first look like skeletonizing, but as the worms grow, the entire leaf is consumed.  Small larvae at this time are easier to control and have inflicted less damage than full grown (35-50 mm long) larvae.  Full grown larvae will soon pupate in upper soil/thatch layer and will not be susceptible to insecticides at this point.

Armyworm larvae are most active early and late in the day, spending the hotter hours down near the soil in the shade. Larvae feed for 2 to 3 weeks before pupating in the soil.  Moths emerge 10 – 14 days later.  The entire life cycle from egg to adult moth takes about 28 days in the warm weather of August and September.

Fall Armyworms in Turf
Paper wasp eating caterpillar. Photo by Cheri Abraham, Field Operations Manager/ Entomologist at US Citrus, LLC

If there is any doubt about whether worms are present, pouring soapy water on the grass (1/2 oz. dishwashing soap/gallon water) will bring them up very quickly.  Heavily infested turf will also have visible greenish-black fecal pellets on the soil surface.  Other indicators of armyworm infestations may include birds or even paper wasps that use the fall armyworms as food.

Control of Armyworms

Control of armyworms and other turf caterpillars is relatively simple once the problem is identified.  There are several pesticides from which to choose depending upon the site you are treating. Consult the UGA Pest Management Handbook or your local Extension Agent for recommendations. Read and follow all label directions when using pesticides.

Armyworms are most active late in the day and at night, so pesticide applications should be made as late as practical for best results.  It is not necessary to water after application but an application rate of 20 – 25 gallons of solution per acre as a minimum will ensure good coverage. Cutting the grass prior to application may improve control, but do not cut grass for 1 –3 days after application.

In addition to the birds and paper wasps mentioned above, a number of other insects feed on armyworms, including tiger beetles and other ground beetles.  Fall armyworms, like many other turf infesting caterpillars can also be heavily parasitized by tiny wasps that kill the caterpillars and cause no harm to humans or pets.  These natural enemies can be conserved by spot rather than blanket spraying and properly timing control efforts.

Looking Forward to Fall Vegetables-Guest Post by Amy Whitney

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The summer vegetable garden is still producing plenty of great food for most Georgia gardeners, but the first frost date is getting close enough that we all can begin to think about fall crops.

As Extension Horticulturist Robert Westerfield says in the UGA publication Home Gardening, “Fall-grown vegetables are usually of very high quality. If you supply water as needed, use pesticides properly and fertilize according to label recommendations, you will be rewarded with tender vegetables in a season when few people are enjoying such delicacies.”

Young Broccoli Plant (PHOTO/Amy Whitney)
Young Broccoli Plant (PHOTO/Amy Whitney)

While many summer vegetables will grow and produce into the fall, cold-hardy crops that can withstand some freezing weather can extend the harvest well into winter for much of the state. The list of these cold-hardy crops includes broccoli, cabbage, cauliflower, spinach, beets, turnips, collards, kale, carrots, and more!  Your local UGA Extension Agent will be able to tell you what fall crops grow well in your area.

When the first frost wilts and blackens the last of our summer crops, the fall crops should already be in place and growing strong.

To get them far enough along that they will reach maturity before a very hard freeze damages the more tender of these crops, they should be planted according to the times listed in UGA’s Vegetable Planting Chart. The dates in the chart are for middle Georgia, so an adjustment of one, two, or more weeks will need to be made in the planting dates for most Georgia counties.

For gardens north of middle Georgia, an earlier planting date is needed to allow time for good growth before their earlier frost. Gardeners farther south can plant later than the recommended dates, since their frost date will be later.

At planting time, don’t forget to follow the soil preparation guidelines that make the summer garden such a success. Add more composted organic matter to the soil, since some will have been lost to decomposition over the hot summer, and remember to provide good nutrition to your crops through fertilizer additions.

These additions can be based on soil test results (preferred) or based on instructions on a home-garden fertilizer package. Careful soil preparation pays off in higher yields, so these are important steps.  Most important of all, though, is to enjoy the beautiful fall weather and bountiful harvest!

Amy Whitney is a Horticulture Program Assistant with Cobb Extension.  She lives in Kennesaw where she is famous for the creative way she grows food crops in her suburban yard.

Happy Gardening!

What is this large spider hanging around in landscapes?

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Female Golden Garden Spider, Image by Hancy Hinkle

The picture is of a Yellow Garden Spider which are often seen in the landscape in late summer and fall. Read on to learn more about this and another fall spider.

Late Summer & Autumn Spiders

Nancy C. Hinkle, UGA Department of Entomology 

Between now and Halloween we will be seeing more spiders around our yards.  The first hard frost will kill them off. Now they are mating and producing egg sacs so their eggs can overwinter and re-establish the population next spring.  There are two orb-weaver spiders with large webs that are most commonly seen.

Barn spiders (Araneus cavaticus) can be found on porches, where flying insects attracted to porch lights get trapped in their webs.  These spiders are nocturnal, constructing a new web every evening and taking it down before dawn.  This rusty brown spider has legs extending about 2 inches, making it look large and noticeable.  These spiders hide during the day, but at night are found in the middle of the web, waiting for insects to be trapped.

The yellow garden spider (Argiope aurantia) is one of the longest spiders we have here in Georgia.  It is frequently found in gardens and around shrubbery where it constructs large webs to entrap flying insects.  The abdomen has distinctive yellow and black markings while the front part of the body, the cephalothorax, is covered in white.

The female yellow garden spider typically remains in one spot throughout her life, repairing and reconstructing her web as it is damaged and ages.  Her web may have a distinctive zigzag of silk through the middle, explaining its other common name, “writing spider.”  Unlike the nocturnal barn spider, the yellow garden spider can be found in its web anytime.  Sometimes a smaller spider will be found in the web with her; this is the male garden spider.

These spiders have been present all summer, eating pest insects and growing.  By late summer they are large enough that people start noticing them.  Remember,Georgia has over 800 species of spiders, all of which are harmless if you leave them alone.  All spiders are more afraid of you than you are of them.

For more information:

Call your local Extension Agent at (800) ASK-UGA1 or locate your local Extension Office.

Stinging and Biting Pests of People

Golden Garden Spiders

Pest Management Handbook Follow all label recommendations when using any pesticide

Tiger, tiger…Aedes albopictus

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Taken from the April 10 issue of Dideebycha, newsletter of the Georgia Mosquito Control Association

Aedes albopictus was introduced into the Port of Houston in 1985 in shipments of used tires from northern Asia. Movement of tire casings has spread the species to more than 20 states since 1985.

The Asian tiger mosquito is a small black and white mosquito. The name “tiger mosquito” comes from its white and black color pattern. It has a white stripe running down the center of its head and back with white bands on the legs.  These mosquitoes lay their eggs in water-filled natural and artificial containers like cavities in trees and old tires; they do not lay their eggs in ditches or marshes. The Asian tiger mosquito usually does not fly more than about ½ mile from its breeding site and generally flies a considerably shorter distance.

Asian Tiger Mosquito range in the U.S.
Asian Tiger Mosquito range in the U.S.

Aedes albopictus associates closely with people and is an aggressive, daytime biting mosquito.  It is native to the tropical and subtropical areas of Southeast Asia, and is now found in 1/3 of the Unites States. New Jersey, southern New York, and Pennsylvania are currently the northernmost boundary of established Ae albopictus populations in the eastern United States.

The tiger mosquito is an important disease carrier in Asia. In North America, Ae albopictus is among the most efficient bridge vectors of WNV. In addition to vectoring exotic arboviruses, this species can also transmit the endemic eastern equine encephalitis and La Crosse viruses in the laboratory and in the field.  It is a competent vector of both Dengue and Chikungunya virus.  In fact, Ae albopictus is a competent vector for at least 22 arboviruses.

A lot of work has been done recently on control of Ae albopictus.  Since it is a daytime biting species and an asynchronous emerger, conventional truck-based ULV spraying doesn’t always work well.  According to one study, an integrated pest management approach can affect abundances, but labor-intensive, costly source reduction is not enough usually to maintain Ae albopictus counts below a nuisance threshold.

References

Fonseca, et al, Area-wide management of Aedes albopictus. Part 2: Gauging the efficacy of traditional integrated pest control measures against urban container mosquitoes. 2013. Pest Management Science, 69 (12): 1351–1361.

Regulatory Restrictions Protect Human and Animal Health

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Nancy C. Hinkle, Ph.D.

Veterinary Entomologist, Dept. of Entomology, University of Georgia

One of the foundations of Integrated Pest Management is prevention, and one of the essential underpinnings of prevention can be regulatory restrictions. If we prevent the introduction of a pest or disease into an area where it does not occur, we avoid the risks associated with the pest or pathogen.

WNV cycleUp until fifteen years ago we had never had a case of West Nile Virus in the U.S. So how did West Nile Virus come to North America? Probably someone smuggled in an infected bird that was carrying the virus. The smuggler didn’t think he was doing anything bad; after all, he had paid good money for the bird and wanted to bring it home with him to New York City. What was wrong with tucking the bird into his pants and not declaring it when the agent asked if he was bringing any living animals as he passed through Customs? Once home, the bird was placed in a cage near the apartment window, a local mosquito flew in and sucked a little of its blood, then flew out and fed on a local sparrow. The sparrow became infected with West Nile Virus, more mosquitoes fed on it and picked up the virus, and a few weeks later dozens of birds at the Bronx Zoo dropped dead of West Nile Virus after being fed on by these infected mosquitoes.

Meanwhile people in Queens were developing high fevers, severe headaches, and nerve problems like paralysis. Even though New York mobilized and started treating for mosquitoes, the virus was already established in birds and mosquitoes. West Nile did not exist in the U.S. prior to 1999; since that year mosquitoes have spread West Nile westward through the continental U.S., resulting in over 1,700 human deaths and ten times that many paralysis cases.

WNV incidence in the US
Source – http://tinyurl.com/qdm4u65

There is a reason the Customs Declaration Form that people entering the U.S. fill out contains the question, “Are you bringing with you meats, animals, or animal/wildlife products?”  While we don’t often think about it, animals in other countries can contain pathogens that we don’t have here in North America and that can be lethal to humans or animal life on our continent. If these hosts get moved into our country, the pathogens can rapidly spread to local wildlife and then to humans.

Before traveling outside the U.S., travelers should visit the Centers for Disease Control website to determine which vaccinations and medications are needed for the areas to which they’ll be traveling. It’s important to follow appropriate precautions to avoid insect bites. And people reentering the U.S. should not bring back with them any living animal or plant, meat, or other animal products. The fellow who smuggled in the West Nile-infected bird had no idea that his action would result in the death of over 1,700 Americans, thousands of horses, and countless wild birds.

Fungicide Efficacy Chart Available Online

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Information from Jean Williams-Woodward, UGA Extension Plant Pathologist

I’ve been asked on numerous occasions for an efficacy table for fungicides labeled for ornamental plants. Well, myself, Alan Windham (University of Tennessee), Kelly Ivors (Cal Poly) and Nicole Ward Gauthier (University of Kentucky) put one together that lists products and their relative effectiveness for managing 14 diseases as part of a Southern Region IPM project. Diseases include:

  • bacterial leaf spots/blights
  • black root rot (Thielaviopsis basicola)
  • cedar rusts (Gymnosporangium rusts)
  • Conifer Tip Blights
  • Downy mildew
  • Fire blight
  • Fungal stem cankers
  • Fungal leaf spots
  • Fusarium stem rot
  • Passalora (syn. Cercosporidium, Cercospora) needle blight on Leyland cypress and other needled evergreens
  • Phytophthora root rot
  • Pythium root rot
  • Powdery mildew
  • Rhizoctonia blight/root rot

The table is not all inclusive, but it’s a start that we hope to expand upon and update. You can find the table here

Editor’s note – You can save the file as a pdf file to your computer. If you print it, do so in landscape format. I find the file to be more easily read as a pdf file on the computer since you can enlarge the size of the page. This is a great resource!

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