Vegetable Press

Vol. 99 No. 6
June 21, 1999

Organic Grower Certification

Dr. Rick Snyder, Vegetable Specialist

The Mississippi Department of Agriculture & Commerce has taken the first steps towards starting an organic produce certification program for Mississippi growers. If you have in interest in selling organically grown vegetables or fruits in the future, pay special attention to the letter from Guy Feltenstein in this issue.

Also, be sure to fill out the questionnaire and return it to him at this address: Guy Feltenstein, P.O. Box 5034, Meridian, MS 39302, or fax the form to (601) 693-3382. People who return the form will be put on a mailing list, and will receive a request for input on the new state legislation.

New Web Page for Central Mississippi Research & Extension Center

Dr. Rick Snyder, Extension Vegetable Specialist

A new web page has been created for the Central Mississippi Research & Extension Center (CMREC). The CMREC is the administrative unit, or "department" for all of the research and extension activities in most of the southern part of Mississippi. It includes three experiment stations &endash; Truck Crops, Brown Loam, and Coastal Plains and all of the researchers at those stations, as well as a number of Extension Specialists in the area.

The CMREC page can be seen at http://www.msstate.edu/dept/cmrec. Links are provided for each of the experiment stations in the region, as well as each subject area covered by Specialists located in the region. Comments and suggestions on how to improve these web pages are always welcome.

"County offices of the Mississippi State University Extension Service provide free, educational resources to serve people in local communities."

New Vegetable Publication - last chance!

Dr. Rick Snyder
Vegetable Specialist

A new regional (multi-state) commercial vegetable publication is now available for Mississippi vegetable growers. The 1999 Commercial Vegetable Recommendations was compiled by Extension Specialists and Researchers in North Carolina, South Carolina, Alabama, Georgia, and Mississippi. This is the first regional vegetable publication for commercial growers in the southeastern United States. It is the result of two and a half years of work by over 40 Specialists and Researchers in the 5-state area .

The goal of this project was to create a "dashboard reference" for vegetables. Therefore, you will find everything you need to grow all vegetable crops in the southeast region. It includes all of the cultural information (including variety recommendations), and all pest management information (insect, disease, and weed controls). In addition, there are many special sections and tables that you will find useful.

The new book (213 pages) is available at cost by filling out and mailing the order form below. Books can be purchased for $13.50, which includes shipping. If you are in the Crystal Springs area, you are welcome to pick one up for $10 and save the postage.

Also included in the purchase price (this time only) is next year's pest management update, which will be mailed to you at no extra charge in the year 2000. This is the last time this publication will be offered this year.

1999 Commercial Vegetable Recommendations

Order Form

Send to: Dr. Rick Snyder, Mississippi State University, P.O. Box 231, Crystal Springs, MS 39059

Include check for $13.50 (includes shipping) made out to "Truck Crops Expt. Station".

Name:

 

Mailing Address:

 

Town State: Zip:

Fire Ant Control in Gardens

Dr. J. Pat Harris, Extension Entomologist

Fire ants are a nuisance and sometimes a very painful pest to farmers and gardeners in Mississippi. It is unlikely we will eradicate this pest any time soon, but we can remove the problem associated with them with good management. This involves reducing their populations to tolerable levels by using safe and effective methods of control.

An application of diazinon granular or liquid, broadcast and soil incorporated in early spring prior to planting will be a big step in managing these pests for gardeners. An early spring application is ideal, because it controls newly developed queens before they leave on their nuptial flights and establish new colonies. A follow-up application in mid summer and another one in the fall is generally necessary. These applications may involve an insecticide drench using diazinon or sevin. Generally, it takes 1 to 2 gallons of water to effectively drench a fire ant mount. A mid morning drench treatment is best when the sun starts warming up the colony.

Broadcast application or mound treatment with diazinon granules may be your best method of control when population densities reach an intolerable level. Granules may be picked up by foraging ants looking for food, taken back to the ant colony, passed through the food chain, and fed to queen ants. Killing queens is the only way to eliminate fire ant colonies. Granules should be applied when ground temperatures are between 70 and 90 degrees F. We don't have a current fire ant bait cleared for use in gardens or vegetable crops.

Summer and fall applications should be applied in the afternoons when temperatures are cooler. Granules may rapidly degrade on hot, sunny days. By the time ants pick them up, heat may have broken down the product, losing its effectiveness. Mound drenches would be most effective and would give a quicker kill of adults and immatures.

When treating mounds with any insecticide, do not disturb mounds before treating. If you do, the colony will immediately take the queen or queens to safety, either deep down in the mound or by moving them laterally to establish satellite mounds.

Fire ant control programs are most effective when every neighbor within a community treats. Take a few minutes to use effective management techniques when controlling fire ants. In doing so, you may be able to spend several months or even a year not having to worry about them.

Save Those Honey Bees

Dr. J. Pat Harris, Extension Entomologist

Apply pesticides after 2:00 p.m. to help preserve our honey bee populations. Bee activity is less at this time. Note: Sevin is one of the most toxic insecticides to honey bees.

Water pH Can Affect Pesticide Performance

Dr. Frank Killebrew, Extension Plant Pathologist

The effectiveness of an agricultural pesticide against a pest can be influenced by many factors, including calibration, rate and timing of application, amount and duration of rainfall following application, possible pest resistance, and the suitability of the pesticide for the intended purpose.

Another factor (often overlooked by growers) that has a bearing is the pH of the water used as a carrier during application. Most fungicides and other pesticides used in vegetable, and fruit and nut production are stable under a wide range of pH conditions. However, some are unstable in alkaline (high pH) water and break down into smaller, inactive molecules through a process known as alkaline hydrolysis.

In most instances, when this process takes place, the pesticide loses much of its effectiveness. Depending on the pesticide and its susceptibility to alkaline hydrolysis, even mildly alkaline water may initiate this chemical reaction. In some cases, significant break down may occur in less time than it takes to apply an entire tank of, for example, a fungicide which is being applied for control of a specific disease. For these reasons, the pH of the water used in preparation of pesticide mixes can be a very important consideration..

Several commonly used fungicides and their half-lives at various water pH levels are listed in Table 1. Half-life is the time required for one-half of the product to break down into an inactive form.

Most other fungicides, insecticides, and herbicides are relatively stable over a wide pH range; however, check product labels for precautionary statements regarding potential alkaline hydrolysis problems. Other commonly used fungicides, such as mancozeb, are stable under neutral or acid solutions. One notable insecticide exception is Imidan, with a half-life of 4 hours at pH 9. Generally, the ideal pH range for most pesticides is 5.5 to 6.5.

The obvious first step in avoiding loss of pesticidal activity due to alkaline hydrolysis is to determine the pH of your water supply. Because of seasonal variation, it's important to measure pH several times over the course of the growing season. Water samples should be collected in a clean glass, or plastic, bottle or jar. When collecting the sample, allow the water to run long enough to flush water that has been standing in a hose or pipes. Also, it's important to determine the pH of the sample soon after collection, because the pH may change if the sample is stored too long. Test kits to determine water pH are commercially available, or the analysis can be performed at the Mississippi State Chemical Laboratory, at Mississippi State University. Check with your County Extension office for details. Or request an analysis through your local water department.

If you determine that your water supply is too alkaline (high pH) or less commonly, too acid (low pH), a buffering agent should probably be added to the spray tank prior to adding the pesticide. Buffering agents are generally available at most farm supply outlets, or in a pinch, one-half gallon of vinegar in 500 gallons of water will typically lower the pH from 8.0 to about 6.5.

One important consideration: to minimize the possibility of breakdown of chemicals in the tank, it's always a good practice to apply the prepared spray as soon as possible after mixing. Also, saving a partially applied tank of a pesticide for application at a later date (especially those previously listed as susceptible to alkaline hydrolysis), is never a good idea.- mix only the amount needed for the job &endash; and don't take extended lunch breaks.

Calendar of Coming Events

Dr. Rick Snyder, Vegetable Specialist

June 26 - Crystal Springs Tomato Festival, downtown Crystal Springs, MS. For information, contact Mrs. Carolyn Kennedy of the Chamber of Commerce at (601) 892-2711, or visit the web page at http://www2.msstate.edu/~ricks/cstomato/tomfest.html .

October 15-16 - Fall Garden Days; at Truck Crops Experiment Station, Crystal Springs, MS. Friday & Saturday, 9 am to 2 pm. For information, call (601) 892-3731.

Dr. Richard G. Snyder, Vegetable Specialist
Truck Crops Research & Extension Center
Mississippi State University
P.O. Box 231
Crystal Springs, MS 39059

PHONE: (601) 892-3731
Fax: (601) 892-2056
Internet: RickS@ext.msstate.edu

New Web Page for Central Mississippi Research & Extension Center: http://www.msstate.edu/dept/cmrec/

NOTE: email addresses and web pages have changed!

Greenhouse Tomato FAQ: http://ext.msstate.edu/anr/plantsoil/vegfruit/tomato/ghtomato/f aq.html/

Vegetable Resource Page: http://www2.msstate.edu/~ricks/

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