Wooly Bugger of a Problem

Question: There is a tree in our yard that has rough warty bark and makes a small fruit about the size of a cherry. The problem is it is dripping a sticky substance on everything underneath its limbs. Do you have any idea what tree this is and what might be the problem?

Answer: The tree is probably a native hackberry or sugarberry tree, but the fuzzy white pest causing the sticky mess is not native. The pest is called the Asian Wooly Hackberry aphid and was first detected in North America on hackberry trees in Georgia in 1996 and in Alabama in 1998. It is not a severe problem every year, but it appears to be a problem this year. The aphid appears to be restricted to native hackberries or their relatives. Although the trees seem to survive the pest flair ups fine, the aphids produce large quantities of the sticky substance called honeydew. As you observed, this creates a sticky mess and promotes the growth of black sooty mold on leaves and on surfaces beneath infested trees. In August and September it can look like a mini snow storm near these trees because the aphids look like cotton fuzz balls. Although this tree is a very tough tree for urban environments, the honeydew can be an annoying problem in residential and business districts where the tree may be used to shade parking lots, walkways or patios.

Some municipalities out west have been treating all hackberry trees in parks and parkway strips with a systemic insecticide called imidacloprid, which is an effective, but relatively expensive insecticide. Researchers at the University of California have had good results with this insecticide even with rates as low as one eighth of the label recommendations. Since it is a fairly expensive product you might try these lower rates and just provide adequate water to make certain what you apply is not wasted. Imidacloprid can provide season long control and can be applied during the growing season after you notice an early infestation in the spring. Treatments are applied as a systemic insecticide, meaning that the product is taken up by the roots of the plant and spreads through all the tissues of the plant. The material may be mixed in a bucket of water and poured around the trunk. It is too late to treat trees now and it won’t be long before the leaves fall off anyway. Just to play it safe don’t use this product near edible plants since it is taken up by plant roots.

The fruit is a favorite fall treat of many birds and other wildlife. This is another reason to use the lowest possible effective rate of insecticides so that the pesticide will be out of the plant by fruiting time. Since there is no research to tell us if the chemical is totally gone by harvest time, I would suggest you avoid eating the fruit.

I talked with the director of the Plant Diagnostic Lab here at the Hanna Environmental Center, Dr. Jim Jacobi and he said “the wooly hackberry aphid does not cause appreciable damage to tree health but from time to time can be quite a nuisance. I would not plant this tree in an area near a parking area or patio, but it can still be used as a specimen tree in a natural area or at the fringes of your property where it won’t cause a mess and can still provide food for wildlife and act as a host plant for at least three species of butterflies that develop on the foliage.”
For more information visit the following web address: http://msucares.com/ and search for Wooly Hackberry Aphid. A great detailed article will be the first link that pops up.

Central South Native Plant Conference

Birmingham Botanical Gardens will host the Central South Native Plant Conference at which I have a small speaking part.

Every three years gardeners, landscape architects, and plant enthusiasts of all kinds are treated to one of the most extensive seminars in the nation, the Central South Native Plant Conference. The symposium, whose theme is “Tough Native Habitats”, will be hosted by Birmingham Botanical Gardens October 17 and 18.

Held about every 3 years since 1989, the conference “is a place for people to learn and to share their knowledge about our regional biological heritage” says program chair Jan Midgley. The focus of the weekend is native plants that call Alabama home. Birmingham Botanical Gardens plays host the 2008 conference, whose goal is to foster awareness, appreciation and increased usage of plants native to the Southeast.

Highlights include an outstanding line up of Southeastern native (and invasive) plant experts in a variety of lectures, break-out sessions, field trips and tours. From novice to expert, everyone is welcome but you need to pre-register. The complete program and registration information is available at www.bbgardens.org . You may also contact Shelly Busby, Special Events Coordinator at Birmingham Botanical Gardens for tickets or with any questions by calling her at 205-414-3965.

Ant Invasion

Question: My house is being invaded by ants. We do not leave food stuff or dirty dishes out so what is causing this ant explosion?

Answer: When outdoor temperatures get hotter and conditions get drier ant problems get markedly worse. The ants are most likely Argentine ants but during an extreme drought fire ants may also come indoors. Both travel in trails into kitchens, offices and bathrooms searching for food and/or water. Even if you are super clean they may come indoors in search of water.
Argentine ants which are small, just 1/8 inch long are very consistent in size. They are native to South America. They were accidentally introduced into the United States more than 100 years ago in New Orleans coffee shipments. Fire ants are likewise South American natives and came in sometime later through Mobile Alabama. Fire ants will often be quite variable in size from 1/16 inch to 1/4 inch long, they have reddish brown bodies and black abdomens and they also bite!
Entomologists say you can reduce your chances of having ants in your home but even the cleanest homes may become infested. To discourage them, rinse all drink cans before placing them into the garbage or recycling bin and empty garbage containers often. And, don't leave any food or drinks out for any length of time. Argentine ants love sugar and will show up to dine on it, literally by the thousands, overnight.
For Argentine ants most experts don't recommend using contact insect killers. These products may make you feel better because you can watch the suckers die in real time but you'll never get rid of them all. For long term controls of both types of ants you have to kill the queen or queens. For Argentine ants the ant bait stations or gels work the best. They don’t give you that immediate satisfaction of a contact killer but the results are much longer lasting.
If you have fire ants the control should involve a little more effort in finding the source. Treating outside will help control ants foraging inside from outdoor colonies. Although unlikely it is possible the ants are nesting in a wall. In this case, a contact insecticide should be used at the nest source and it may require assistance from a professional pest control operator to locate the nest. More likely, the fire ants are in an outdoor mound and foraging for food or water indoors. You might say they live in the suburbs and commute in to work. If you decide to treat indoors make sure the product you select is labeled for use indoors. Read and follow the directions on the product label for best results. Be sure to keep products away from children and pets. Again, eliminating the outdoor colonies will be critical to ridding your home of this menacing pest.

For more information visit the newest nationwide Extension website: www.extension.org and check out the fire ant portion of the site. This site has a wealth of information that you can trust has been well researched and is very up to date.

Spurweed is a Pain (click title for audio file)

Most of the time homeowners view weeds as a nuisance in lawns, but for most, these plants only cause ‘mental anguish’ – not physical. Well, spurweed (also called lawn burrweed) is a lawn pest well known throughout the warmer-climates of the south for its potential to inflict genuine physical pain to people and pets. Dr. Jeff Derr, Extension Weed Specialist at Virginia Tech, has indicated that spurweed is increasing in importance as a serious lawn weed every year throughout Virginia’s Tidewater region, and it has long been noted as a serious pest in the our area of the deep south here in Alabama.
This winter annual broadleaf plant has opposite leaves that are twice divided into very narrow lobes. It looks a lot like parsley in appearance but if you have any questions regarding its identification, you probably want to contact your local extension office for assistance.
Spurweed becomes a major problem in the landscape in mid-late spring when it flowers and sets fruit that are surrounded by razor sharp spines. It is a nuisance to pets, with the sharp spines potentially getting lodged into their paws. And all it will take is one step on this weed by someone walking across the lawn either in bare feet or loose fitting sandals to quickly identify that the weed is present— everyone will know from the shriek of pain! Of course, spurweed on athletic fields is even of more concern for athletes that might be doing a lot of sliding or tackling as part of normal play in spring sports.
There is little that can (or should) be done about spurweed after it has flowered and produced its troublesome spines. If you have it, anticipate that it will be producing plenty of seed to support next year's population and make a note on your calendar for the next fall to treat IF you identify it in the turf. Spurweed can be controlled by an application of many fall preemergent herbicides applied in September. Field research trials have shown excellent results in the fall pre-emergent applications of isoxaben, sold as Gallery and Green Light Portrait. This chemical is specific to broadleaf weed control, making it a compatible chemical for most for fall lawn seeding programs. You can also control spurweed quite easily with most two and three-way phenoxy broadleaf post-emergent herbicides (products containing 2,4-D, dicamba, MCPP or MCPA etc.) if you treat the weed while it is young and actively growing in the fall or early winter.
This is one of the pests that causes much more concern than just a disruption of turf uniformity and appearance-- it is a pest that actually inflicts physical pain if not managed appropriately.

Originally prepared by Mike Goatley, Virginia Tech with some modification by Tony Glover, Alabama Cooperative Extension System

June Bugs (click for audio file)

Question: My yard has been invaded by green bugs that are about twice the size of Japanese beetles. They buzz around my kids and pets and I am concerned about one of them being bitten or stung.
Answer: The pest is likely a June beetle or as I called them growing up, a June bug. Green June beetles are velvet green with orange or rust stripes along the outer margins of the wing covers. Beetles can range from ½ to 1 inch in length and as you described, they are twice as large as their more destructive relative, the Japanese beetle. Peak flights for this insect started in late June and will continue another couple weeks.
The adults out buzzing around in your yard are probably seeking a mate or there is a good food source that they are attracted to. The adults primarily feed on over ripe fruit but sometimes they feed on leaves of things like peach trees. Since they do have chewing mouthparts it may be possible to be bitten by them but more than likely if you feel something like a bite it is from their spiny legs and they don’t have a stinger. Even though they seem aggressive while buzzing around and I have been scared out of my wits when disturbing a group of them while picking peaches or blackberries I have never been bitten by them.
They will soon complete their lifecycle and lay eggs for a new generation. The eggs will develop into a grub that will develop and overwinter in the soil. These grubs are different from most grub species in the southeast in that they come out of the ground at night and move from one place to another. Even more unusual they crawl on their backs when moving. One of my kids used to do that as an infant so it may not be as unusual as I think. When disturbed the grubs curl up into a C-shape, much like my teenage girls do when I ask them to wash the dishes.
The adults can cause damage to the turf while nesting but it is normally not severe enough to treat with an insecticide. The grubs can actually be beneficial in the turf because small populations of them will aerate the soil while tunneling. However, large populations can cause excessive tunneling causing the grass roots to dry out and die in patches. If control of grubs appears warranted do so in August and September when the grubs are small, close to the surface and more susceptible to pesticides. Most recommended pesticides work best after an irrigation or a soaking rain.
I am not sure how wide spread this problem is in recent years because we get so many more calls about the dreaded Japanese beetle which causes much more damage to ornamental plants. Normally I don’t pay a lot of attention to what one or two folks say about pest numbers but if one of the people is your mother you better listen. In this case while visiting my mother in Cullman Alabama recently she asked me, “do you know, where have all the June bugs gone?” to which I responded, “No – but if you hum a few bars I may be able to pick it up”. After I picked myself up and brushed off a little I asked her what she meant and she swears she has not seen any June bugs since the Japanese beetles arrived a few years back. I would be interested to know if anyone else has observed a decline in June beetles around your home in the last few years. Send me an email with your observations to satisfy my mother’s curiosity. You may drop me a note or a question at gloveta@aces.edu . For more information and control options visit our web site at http://www.aces.edu/ and go to the publications area. We have two relevant publications you may want to read: “Biology and Control of the Green June Beetle” and “Controlling White Grubs on Lawns and Turf”.

Tomato Wilting

Question: Some of my tomato plants have wilted and died quickly and I noticed a white powdery substance on the base of the stem - any ideas?

Answer: The description you gave is very typical of "southern blight", also known as white mold and stem rot, and it is caused by the soil-borne fungus Sclerotium rolfsii. We have had numerous reports about this disease in the last few days. The disease is a common problem on vegetables, especially tomatoes, as well as most other broadleaf crops such as pepper, eggplant and beans. Plants of any age can be attacked if environmental conditions are suitable. Development of southern blight is favored by moist conditions and high temperatures (more than 85 degrees F).
Generally, the first above-ground symptoms are leaf yellowing and wilting of infected plants. The stem at the soil line often appears soft and sunken (cankered) and develops a brown to black discoloration both internally and externally. Under moist conditions, a white fungal growth can be seen on the lower stem near the soil surface; on fruit in contact with the soil; and on crop debris on the soil around the base of the plant. Spherical, light brown, mustard-seed size ( 1 to 2 mm) objects called sclerotia often form in the mycelium. Under dry conditions, fungal mycelium and sclerotia may not be visible. However, if southern blight is suspected, placing a section of the lower stem and a moistened paper towel in an enclosed plastic bag for 24 hours will stimulate formation of a white mat of fungal growth. This would be diagnostic for southern blight.

The fungus is spread as mycelium in infested organic matter or as sclerotia in infested soil. Infection usually takes place at the soil surface but may also occur below the soil line. The fungus may spread more than 3 feet through the soil and from plant to plant within a row. It is common to see five or six infected plants within a row killed. Sclerotia, produced on crop debris and dying plants, serve as inoculum for the next crop.

Control of southern blight is difficult to achieve when inoculum levels are high and environmental conditions favor its development. Rotations with crops such as corn, and grain sorghum will reduce disease. Rotations are most effective when tomatoes or other susceptible crops are not planted in the same area more than once every 3 to 4 years.

Deep-plowing the soil to bury crop debris and the fungus will also help reduce inoculum. Wider plant spacing to improve air movement and roguing infected plants will aid in reducing disease development and spread within a field. Adding copious amounts of organic matter may help as well. The information for this blog camer from the Alabama Cooperative Extension System - Tomato Wilt Disease publication.

Okra Problems

Question: Why is my okra growing so slow this year and making so few fruit?

Answer: In the mid to deep south this has been an unusually cool spring (dang global warming - you never know how it will manifest itself ;) ). Okra is a heat loving plant that simply will not grow when the soil or the air temperature is cool. It is a hibiscus and cotton relative that loves the heat. Interestingly, the blooms are only open for a day and if not pollinated they will shrivel up and fall off without forming a pod.

Be patient and keep the plants watered and actively growing and when the weather really heats up and its too hot to be in the garden they will be bearing when other vegetables have bit the dust.

For a little more information and interesting history visit this UGA site.