Texas Agricultural Extension Service
The Texas A&M University System


OCTOBER, 1996 VOL. 7, NO. 10

IN THIS ISSUE:

DENGUE FEVER
DON'T OVERLOOK STORED PESTICIDES WHEN PREPARING FOR A STORM OR FLOOD
FOOD QUALITY PROTECTION ACT
IR-4 FOOD USE WORKSHOP
NEW PESTS IN GRASSES
MERIT NOW AVAILABLE TO THE GENERAL PUBLIC
TICK REMOVAL
TEXAS PRODUCE CONVENTION
CURRENT ORNAMENTAL DISEASE SITUATION
NOTICE TO EXTENSION FACULTY
SECTION 18 FOR DUAL ON SPINACH

DENGUE FEVER:

I am sure by now that everyone is aware of the outbreak of dengue fever in Mexico and the first cases in the LRGV. This is of entomological concern because this disease is vectored by mosquitoes and the only method of battling the disease is to control the vector. The primary vectors are Aedes (genus) mosquitoes, especially Aedes aegypti. This mosquito is considered a small-container breeder (it lays eggs in small containers), a behavior that likely derived from breeding in tree holes and other natural 'containers' in response to opportunities provided by man. Eggs are laid singly on the sides of the 'container' at or near the water line and will complete development and hatch if they are flooded after four days. If no additional rain occurs, the eggs can withstand desiccation for up to a year and will still hatch when flooded. All of this leads to the recommendation for removal or drainage of artificial containers (empty cans, old tires, vases in cemeteries, etc.) to help reduce the mosquito population. This obviously is of benefit only in reducing the population in the near future (hatching to adult takes 10 to 14 days) and has no impact on adults (adult females probably live a couple of weeks in the heat of the summer but can live much longer with abundant food and cooler temperatures). The only method to significantly reduce the adult population is to treat with insecticides.

As a side note, it is interesting (to me anyway) that none of the reports I have seen or read have mentioned that Aedes aegypti is known as the yellow fever mosquito. This is probably because most people today are not familiar with yellow fever. The lack of experience with yellow fever is a testimony to the effectiveness of human disease control through insect vector control and the contribution of pesticides to human health.

Stormy Sparks
Associate Professor & Extension Entomologist

DON'T OVERLOOK STORED PESTICIDES WHEN PREPARING FOR A STORM OR FLOOD -----

I know that right now most of us would welcome a little flooding, particularly above the dams, but flooding also presents many problems. One of these is the potential for pesticide contamination problems associated with flooded pesticide storage facilities. Farmers and homeowners often prepare for damage but sometimes overlook potential complications from toxic materials impacted by wind and flood waters. During the 1985 flood in Virginia, authorities and landowners spent months dealing with chemical containers picked up by the flood waters. The lack of protected storage of chemicals resulted in contaminated waterways, land, and in some cases poisoned domestic and wild animals. This also resulted in direct economic loss to the individuals who had purchased the pesticides, and at the cost of many of our newer products, it would not take a great deal of volume to represent a significant loss.

Anyone storing pesticides at home, on the farm or in a business should take safeguards to move these chemicals to higher ground to prevent a cleanup and financial loss due to flood damage. Dr. Mike Weaver (Extension Pesticide Coordinator, Virginia Tech Pesticide Programs) put together a short list of suggestions for protection of pesticide storage facilities which we will be glad to provide to any interested individuals.

Stormy Sparks
Associate Professor & Extension Entomologist

FOOD QUALITY PROTECTION ACT -----

On August 3, President Clinton signed the Food Quality Protection Act of 1996 into law. The bill added more than 70 pages of amendments to FIFRA. FIFRA only has about 79 pages, so the act essentially rewrote the nation's primary piece of pesticide legislation. The overall impact of this bill is uncertain, however, major changes are going to occur in the way EPA regulates pesticides in this country.

The act also amended the Federal Food, Drug, and Cosmetic Act (FDCA) to exempt pesticides from certain regulations under the Delaney clause. It left the Delaney clause untouched and Delaney will still govern additives, dyes, preservatives, and packaging materials used in processed food. Instead, the Food Quality Protection Act amended other sections of FDCA to exempt pesticide residues from regulation under Section 209. The new law regulates pesticide tolerances under other sections of FDCA and FIFRA and gives the EPA Administrator broad powers to establish tolerances for pesticide residues on processed and unprocessed foods.

Although the act exempts pesticides from Delaney (and does a few other potentially beneficial things), it is unclear what the overall effect will be on pesticide registration, particularly minor use registration. A variety of new 'concerns' will likely be addressed in the new regulatory procedures, including different effects on women and children, estrogenic effects of certain pesticides, and more detailed examinations of chronic effects and exposure. The immediate effect has been a tremendous reduction in work on pesticide registration while EPA figures out how to address these new regulations.

Stormy Sparks
Associate Professor & Extension Entomologist

IR-4 FOOD USE WORKSHOP -----

IR-4 recently held its annual Vegetable Prioritization Workshop (they also had an ornamentals section but I did not participate). Texas had strong participation in this workshop with representatives from Texas A&M, USDA-ARS and TVA. Each year at this workshop, all proposed IR-4 projects for 1997 are examined and prioritized by the participants. In this year's workshop, each project was ranked as an A (definitely work on in 1997), B (probably work on in 1997), C or D. Out of all projects (insecticides, fungicides, herbicides and rodenticides) considered, the workshop was targeted to end up with about 200 A and B rankings (total). IR-4 indicated it would likely be able to work on about 150-175 projects. Because of Texas' strong showing at this workshop, we were able to get most (if not all) of our priority projects within the A and B groupings. Texas' recent push for increased activity in IR-4 is beginning to show and should prove beneficial to Texas producers.

Stormy Sparks
Associate Professor & Extension Entomologist

NEW PESTS IN GRASSES -----

Dr. Bart Drees recently attended the Valent 1996 Turf and Landscape Management Seminar. In his report from this meeting he noted that eriophiid mite species are becoming major pests of buffalo grass and zoysia grass. These mites feed under leaf sheaths and cause emerging grass blades to 'stick' in the sheath, forming a loop-like configuration. If any of you run across this type of damage, pull some samples and let's check it out.

Stormy Sparks
Associate Professor & Extension Entomologist

MERIT NOW AVAILABLE TO THE GENERAL PUBLIC -----

Merit insecticide (same active ingredient as Admire) is now labeled for use by homeowners for control of white grubs and mole crickets in lawns and landscape areas. PCOs have had this product available for a couple of years, but now it can be sold directly to homeowners. Although the product is effective against a variety of sucking pests (whitefly, aphids , etc.) the current label is for white grubs and mole crickets only. Our most likely use at this time will be for white grubs. It is apparently highly effective when used properly. It will still require treatment in the spring‹target the early instar grubs‹but has a longer residual action than products homeowners currently use. This longer activity (and possibly improved activity) may allow for a little more 'play' in the application window, but we still do not have products that are effective against large larvae. Once damage appears in the lawn, you are dealing with an educational opportunity (tell them the proper approach for next year).

Stormy Sparks
Associate Professor & Extension Entomologist

TICK REMOVAL -----

Based on a couple of e-mails I received recently addressing an article evaluating various methods of tick removal, the old tried and true method of gently pulling the ticks off with fingers or forceps still appears to be the best bet. Use of products such as petroleum jelly, fingernail polish, alcohol (applied externally I assume) and hot matches failed to induce detachment of some ticks. These methods may also cause the tick to regurgitate which could add to your problems. The bottom line appears to be‹pull the tick gently so that it releases and does not leave mouthparts or head attached to your skin, then clean the bite site.

Stormy Sparks
Associate Professor & Extension Entomologist

TEXAS PRODUCE CONVENTION -----

The 1996 event was quite good and most of us are looking forward to next year when Texas Fruit Growers Association, Texas Apple Growers Association and Texas Blueberry Growers Association again join with Texas Citrus Mutual, Texas Vegetable Association and the Texas Produce Association in this event. That one will be at the Bayfront Plaza Convention Center in Corpus Christi on September 10-13, 1996.

The good news for us in Extension is that we were invited to participate without having to pay the registration fee, only for any meals in which we participated. Hopefully, this policy will continue.

Julian W. Sauls
Professor & Extension Horticulturist

CURRENT ORNAMENTAL DISEASE SITUATION -----

Rains in late August and early September have led to a resurgence of plant diseases. I have confirmed take-all patch on several samples of St. Augustine grass lately. There is still no clear understanding of how it operates in our climate, although we now suspect that the fungus can cause root rot throughout much of the warmer part of the year. Judging from the sudden influx of samples, it seems that the fungus grows well under warm, wet conditions. I recommend that whenever the symptoms of dead patches are found in lawns, one of the first things to be done is to check for this fungus. Bayleton, which is the fungicide available to homeowners for control of this disease, should be applied. However, the cultural practices used by the homeowner should also be evaluated and changed where appropriate. As a generalization, I find that the common mistake made is frequent waterings (e.g daily) of a short duration.

Rainy weather will also favor fungal disease development in foliage of ornamentals. A common disease of periwinkle is Phytophthora aerial blight. Aliette or Subdue are fungicides that can be used to control this disease, but homeowners could probably achieve an acceptable control by such cultural practices as spacing plants to allow air to circulate and quickly dry foliage, or the use of mulches to prevent splashing of soil onto foliage. I recently identified an anthracnose disease on periwinkle that may be mistaken for Phytophthora aerial blight.

Anthracnose is caused by the fungus, Colletotrichum gloeosporioides. It infects the shoots, resulting in leaf wilt. It can also infect leaves. Infected portions of the stems are bleached in color and have small, black fruiting bodies. With a very good hand lens, or a microscope, dark brown hairs can be seen in the fruiting body, which give it the dark color. The cultural practices mentioned above apply for control of this disease. Duosan or Zyban are the fungicides of choice for this disease.

Additionally, rainy weather will favor the development of fruiting bodies of wood decay fungi. These will be seen about two weeks after the rainy period. Ganoderma is the most common species seen. It is easily recognized by the brown, varnished appearance on the upper surface of the fruiting body. There have been other wood decay fungi documented in south Texas. There is no control recommendation for any of these fungi. Homeowners should be advised to take out the tree once there is a noticeable decline in the vigor of the tree (e.g. numerous dead branches).

Thomas Isakeit
Assistant Professor & Extension Plant Pathologist

NOTICE TO EXTENSION FACULTY -----

Effective September 17, 1996, new state regulations allow ALL Extension faculty (county agents and specialists) to provide pesticide applicator training to BOTH private and commercial / noncommercial applicators.

In addition, a 2-CEU limit has been increased to 3 CEUs for continuing education credits that Extension faculty may issue without advance course approval from the Texas Dept. of Agriculture. Courses worth more than 3 CEUs MUST be submitted to TDA for approval at least 30 days before the event.

Remember, course content must provide 1 hour of instruction per CEU. The content must pertain to the safe, legal or effective use of pesticides or the reduced use of pesticides (e.g. through IPM).

More information about these developments will follow soon in a mailout.

Stormy Sparks
Associate Professor & Extension Entomologist

SECTION 18 FOR DUAL ON SPINACH -----

One thing that you should be aware of, particularly if you have spinach producers in your county is that Dual herbicide has again received a section 18. But, and this is a big one, producers may or may not be able to sell the crop if Dual is used for weed control. What has occurred is that the EPA has given the go ahead for Dual, so it is legal to use it, but item 10 of the section 18 states that being able to harvest the crop for commerce is contingent upon final review by EPA. So, we have a catch 22 going on this one.

Other restrictions in the section 18 that producers should be aware of include use in spinach production to 29 specific counties in the Winter Garden, High Plains and Lower Rio Grande Valley of Texas. Ciba the manufacturer, will enter into indemnification agreements with local food processors including Value Frozen Foods, Dean Foods Vegetable Co., Del Monte Foods, Allen Canning Co. and Bush Brothers. Commercial producers that are planning on using Dual or Dual 8E on spinach must have a signed grower agreement with one of the above mentioned food processing companies and a signed waiver of liability.

The only other alternative for pre-emergent weed control in spinach is Ro-Neet. This material has generated mixed success, but as Frank Dainello found in his studies, the secret to successful weed control with this material is good soil preparation and incorporation of the material. If applied correctly Ro-Neet should give adequate control of weeds in spinach fields.

Lynn Brandenberger
Associate Professor & Extension Vegetable Specialist

JULIAN W. SAULS, Ph.D.
Professor & Extension Horticulturist
2401 East Highway 83
Weslaco TX 78596
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