“WHAT’S HAPPENING?”

The University of Tennessee/Agricultural Extension Service

Entomology & Plant Pathology - EPP #60

Volume No.7 - May 21, 2004

EXOTIC GIANT AFRICAN SNAIL ALERT

by Beth Long (Source: APHIS Press Release)

Giant African snails are being used increasingly in science lessons in schools. These snails are illegal in the continental United States because they are highly invasive, and can cause extensive damage to important food crops and other agricultural and natural resources. These snails can also pose a risk to human health. The U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS) is interested in finding these snails, and encourages those using these snails in classrooms, nature facilities or keeping them as pets to turn them in to APHIS voluntarily without fear of a penalty.

If you have a giant African land snail, PLEASE DO NOT RELEASE IT INTO THE ENVIRONMENT OR GIVE IT AWAY. Instead, report it to TDA at (615) 837-5338, or to the USDA APHIS office at (615) 781-5477.

“Giant African land snail” is the common name used to describe any of three snail species native to Africa and considered serious agricultural pests in the United States. The giant African snail (Achatina fulica), the giant Ghana tiger snail (Achatina achatina), and margies (Archachatina marginata) are large, terrestrial snails that reach up to 20 cm (8 inches) in length and 10 cm (4 inches) in maximum diameter. These snails are about the size of an average-size adult fist. The brownish shell with darker brown vertical stripes covers at least half the length of the snail.

Giant African snails have a voracious appetite. They are known to eat at least 500 different types of plants, including peanut, beans, peas, cucumbers, and melons. If fruits or vegetables are not available, the snails will eat a wide variety of ornamental plants, tree bark, and even paint and stucco on houses.

These snails also reproduce rapidly, laying as many as 100 to 400 eggs in a single session. Snails contain both male and female reproductive organs, and can lay up to 1,200 eggs per year.

A giant African snails toll-free number, 1-888-703-4457, was established for persons wishing to voluntarily surrender their giant African snails or report these snails as part of PPQ's snail amnesty program. Callers can leave contact information on the toll-free line and it will be forwarded to the appropriate state officials for follow-up.

More information on these and other exotic pests is available on the APHIS web site located at http://www.aphis.usda.gov/ppq/ep/emerging_pests.html

PYTHIUM STEM ROT OF TOMATOES

by Steve Bost

We are seeing quite a few tomato samples with Pythium stem rot. Young plants are pale and stunted and some become chlorotic and die. The lower stem shows dark rot and the roots are not developed. Pythium stem rot is a young plant disease - - if the plant survives, it will develop tolerance to the fungus and produce a normal plant. Gardeners can mound some soil up around the stem to encourage root development above the rot. There are no effective chemical treatments for homeowner use. Commercial growers can use Ridomil Gold or Ultra Flourish injected into the drip or as a directed spray to the base of the plants. This treatment will not rescue infected plants, but will protect uninfected plants. Pythium stem rot is usually found in poorly-drained areas of the field.

ORNAMENTAL UPDATE

by Frank Hale

Periodical cicadas have emerged from the ground in East Tennessee but are apparently vary scarce in Middle and West Tennessee. So far I have not had any confirmed reports of emergence from this part of the state. Let me know where they are occurring in your individual counties if you have not already done so. This will allow me to update the current distribution map.

There are many types of saw flies out now. They have the potential to defoliate trees, shrubs and other plants. Usually, an occasional defoliation does not adversely effect the health of the plant. After the defoliation, the plants tend to put out new leaves and continue to grow. The maple petiole borer has been particularly noticeable this year causing many leaves to drop from infested sugar maples. Usually less than a third of the leaves drop and if the leaves were not littering the ground, you may not have known that the tree had lost any foliage. Pine saw flies have been reported feeding on pine along I-24 between Murfreesboro and Nashville. We have also had reports of saw flies on pin oak and the dusky birch sawfly on birch. Other saw flies to be aware of include the dogwood sawfly, a sawfly on mock orange, and a sawfly on hollyhock. Many common ornamental insecticides are labeled for control of saw flies including Conserve SC. The Bt insecticides (Dipel and other brands) are not effective on saw flies (Order Hymenoptera) that usually have 8 pair of fleshy prolegs on the abdomen. Bt is specific for control of lepidopterous caterpillars which usually have no more than 5 pair of prolegs.

Oak phylloxerids (Phylloxera spp.) are very tiny, aphid-like insects that feed on the buds and foliage of oak trees. The new foliage is severely distorted and heavy infestations can stunt tree growth and weaken trees during spring and early summer. The insects are only 0.3 to 0.6 mm long, spiny somewhat wedge shaped and unlike aphids, they lack the tailpipe looking cornicles. For control, we recommend a dormant oil spray in February-March followed by treating the nymphs when they first appear in April to early May and before much damage is seen with Bioneem, Azatin, Ornazin, Sevin, Carbaryl, Tempo, Decathlon, Dursban, horticultural oil, or insecticidal soap.

Cottony camellia scale is fairly common on holly. The female overwinters on the underside of the leaves. In May, they each lay an egg mass covered with white, waxy filaments called an ovisac. Control of the overwintering females with a dormant oil application directed primarily to the underside of the leaves is the best approach. If this was not done, apply a horticultural oil spray now to kill the eggs and any emerged crawlers. In a week, when any surviving crawlers are active, treat again.

Eriophyid mites that cause leaf and stem galls are called gall mites. Some eriophyids called rust mites feed on leaves or needles with their piercing-sucking mouthparts, removing the cell contents which causes a yellowish brown or grayish discoloration to the foliage. Privet rust mites are in high number on privet. Other rust mites have been reported on hemlock and elm. Horticultural oil sprays are a good choice for control of these rust mites.

Flatheaded appletree borers and two lined chestnut borers are probably our most damaging tree borers. The flatheaded appletree borer attacks some 30 species of shade and ornamental trees such as maple, oak, sycamore, dogwood, crabapple, hickory, linden, tuliptree. The two lined chestnut borer attacks oak, chestnut, chinkapin, and occasionally beech. Now (Mid-May) is the time to apply permethrin (landscape or nursery) or Dursban (nursery only) as a protective insecticide spray followed by a second spray in late June. Imidacloprid (Merit, Marathon, Bayer Advanced Garden Tree & Shrub Insect Control) can be best applied as a soil drench in the late winter through mid-April. This systemic insecticide will protect against new infestation by the flatheaded borers and will also control aphids and Japanese beetle adult feeding. Although not specifically listed on imidacloprid insecticide labels, oak phylloxerid damage could probably be prevented by using imidacloprid in February to March.

IMPLICATIONS OF PHYTOPHTHORA RAMORUM DETECTION IN TENNESSEE

by Alan Windham

Phytophthora ramorum, the causal agent of Sudden Oak Death (SOD) has been confirmed on camellia in two Tennessee nurseries (one in Shelby Co. and one in Bradley Co.). This fungus has a growing host range that includes ornamental plants such as camellia, rose, pieris, mountain laurel, rhododendron and viburnum. In the United Kingdom, P. ramorum has been found attacking northern and southern red oak.

As of May 13, trace forward surveys have confirmed P. ramorum in 97 nurseries/garden centers in 14 states. The number of nurseries/garden centers with positive samples in the Southeast are: Alabama (1), Florida (5), Georgia (13), Louisiana (5), North Carolina (9), Tennessee (2), Texas (5), Virginia (1). The infected camellias originated from Monrovia Nursery, Azusa, CA

In the Bradley Co. nursery, the infected plants arrived (one week after I had surveyed the nursery for P. ramorum) from Monrovia in Azusa, CA in July 2003; P. ramorum was not detected on these plants until April 2004. Most of the plants remain on site; no doubt that some are probably in landscapes in East Tennessee. In North Carolina, many of the nurseries had sold all of their camellias by the time inspectors from the NC Dept of Agriculture arrived to collect samples.

Predictably, CA nursery organizations, CA Dept of Ag and some nursery trade magazines are downplaying the potential for damage and trying to minimize long term damage to the CA nursery industry valued at three billion dollars. Also, just as predictable, SOD researchers at UC Berkeley and UC Davis have been under attack by these same organizations. Some green industry spokespersons have said that P. ramorum is probably already in the Eastern Forests; that no one has bothered to look. With that statement, I can disagree. In 2003, TN, GA, NC, SC, and VA ran a pilot survey of nurseries and forests for P. ramorum. P. ramorum was not detected in any of these five states (that is until the camellias arrived from CA).

Will P. ramorum be a problem in the Southeast? Will this fungus cause major problems to native oaks in southern forests? No one really knows at this point. We really don’t know how this fungus will survive in our climate or how aggressive of a pathogen it will be on southern oaks. One thing that is safe to say is that P. ramorum probably has a toe-hold in scattered landscapes across the Southeast. A national survey now underway should let us know, at least in nurseries, if P. ramorum has spread to additional hosts and new locations. Developing . . . . .

EPP/PSEP INFORMATION HOT LINE

by Gene Burgess

Anyone who has questions concerning pesticide certification and/or licensing process, may call the Entomology & Plant Pathology (EPP)/Pesticide Safety Education Program (PSEP) Information Hot Line at 865/974-0875.

The hot line will address the following topics:

1. Information on how to order pesticide certification and licensing study materials and the source of PSEP publications and forms.

2. Information as to whether you need to be certified, licensed or chartered.

3. Information on certification categories and study materials to order.

4. Information about the various licensing categories and study materials to order.

5. Information on the Recertification process.

6. Information about the licensing process of Pest Control Operators.

ELECTOR

by Gene Burgess

Elanco has now made available the first product in the new spinosyn class, Elector. It offers effective control of flies and lice as well as superior safety. It is an ideal rotational alternative to older and in sometimes resistant products on the market. It has a relative recent label on other products, and now the first time for livestock.

It is labeled as a pour-on or dilutable spray for control of horn flies and lice on lactating and non-lactating dairy and beef cattle. It is also labeled as a dilutable spray for control of stable and house flies on agricultural animal premises.

It is available in both 1-liter and 5-liter bottles. The cost is around $35.00/L.

Dose information is as follows:

Pour-on: 4 mL per 100 lbs body weight

Animal Spray: Dilute 10 oz (approx. 300 mL) to 5 gal water. 1-2 qt of coarse spray per animal or until runoff over whole body surface

Premise spray: Dilute 20 oz (approx. 600 mL) to 5 gal water. Use approximately 1 gal of diluted spray per 500-1000 sq ft.

This appears to be a good substitute for horn flies and face flies that may be resistant to pyrethroids and phosphates.

NEW CORE MANUAL UPDATE

by Gene Burgess

EPA has had a committee work on revising the national core manual for pesticide applicators. They are behind on its production. The status of the manual is as follows.

All chapters have been written and the core manual subcommittee has been working with a designer/illustrator/printer. The manual will be available in electronic format. Hard copies will also be available. The manual will hopefully be available from EPA this fall. Then, we can make it available to Private and Commercial Applicators shortly thereafter.

SUDDEN OAK DEATH UPDATE

by Beth Long

A new SOD find was made in Pennsylvania this week. It was in the possession of a homeowner and the host was a bonsai Camellia. This is the first positive sample from Pennsylvania.

The Eastern Region trace forward positives currently include: Alabama (2 positive samples), Florida (5 positive samples), Georgia (43 positive samples), North Carolina (17 positive samples), Pennsylvania (1 positive sample), Tennessee (3 positive samples), and Virginia (1 positive sample).

A National SOD survey is beginning and samples will be collected by the Tennessee Department of Agriculture during the next few weeks.

PSEP QUESTION AND ANSWER

by Gene Burgess

Question 5: What are the types of pesticide applicators and how do they become certified?

There are two types of applicators, Private and Commercial. Private Applicators become certified by attending a training session offered at your local Extension Agent office. There is a certification fee is $10, which is sent to TDA.

Commercial Applicators may attend training at the state level, which is optional. But, a Commercial Applicator exam must be taken and passed in their category of work. This exam consists of questions from the CORE or general standards manual and the respective category of service. These exams are offered several times a week at various county Extension offices and Tenn. Dept. Of Agriculture offices across the state. One must prepay a fee of $15 to TDA in order to take the exam. TDA will then assign you a date to take the exam. One should indicate on the prepay form if you intend on taking one of UT’s training seminars in Knoxville.

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.

The Agricultural Extension Service offers its programs to all eligible persons regardless of race, color, age, national origin, sex, veteran status, religion or disability and is an Equal Opportunity Employer.

COOPERATIVE EXTENSION WORK IN AGRICULTURE AND HOME ECONOMICS

The University of Tennessee Institute of Agriculture, U.S. Department of Agriculture,

and county governments cooperating in furtherance of Acts of May 8 and June 30, 1914.

Agricultural Extension Service Charles L. Norman, Dean