An Interesting Way to Control Colorado Potato Beetle - The Plastic Lined Trench Method

I'm sure that most of you are familiar with the Colorado Potato Beetle (CPB) that attacks the foliage of potatoes, as well as tomatoes, eggplants, and other members of the nightshade family. You can easily recognize the adult stage of CPB as a 3/8" by 1/4" beetle with an orange head with black dots and black and white stripes running down the back. These adult beetles overwinter in the soil of brushy and wooded areas along the edges of the field. The beetles emerge in early spring for a brief feeding period and then begin depositing eggs. You can find these eggs in clusters on the undersides of leaves. The eggs are orange to yellowish in color. These eggs will hatch as red, humpbacked larvae in approximately 4 to 9 days. These larvae will feed on the foliage for about 3 weeks before descending down into the soil to pupate. Five to 10 days after pupation takes place, the transformed larvae will emerge as new adults and continue the cycle. This cycle is usually repeated 3 times per year in North Carolina. Feeding damage is done by both the adults and larvae.

CPB is beginning to show some resistance to insecticides, so other control methods are being sought. One method that is being used successfully in Canada and New York is the plastic lined trench method. Some work is being done in North Carolina using this technique and, so far, the results look promising. You may want to give this method a try for yourself. Here is how it is done.

Dig a trench that is about 12 inches deep, 12-16 inches wide, and surrounds the entire field or area that your crop is to be grown. Line this trench with a black plastic film. The idea is to place this trench between your crop and the overwintering area of the CPB adults. As these adult beetles emerge in the early spring, they will crawl from the overwintering site to your crop. When they encounter the black plastic lined trench, they attempt to cross it and fall into the trench. The beetles cannot escape this trench due to the plastic lining, and they eventually die in the trench.

Potato is normally the first crop that is exposed to CPB. I suggest that, with potatoes, you install this trench at planting or shortly afterwards and before seedling emergence. With tomatoes and eggplant, install the trench before planting. This technique does not eliminate the need for careful scouting of CPB or other pests and should not be totally relied upon until more research is done or until you have experimented with it enough to see if it works for you. This technique, however, should significantly reduce the number of CPB adults reaching your crop from the overwintering sites and reduce some of the input involved with other control methods. Try this method with a portion of your crop and let me know how it works for you.

Certain Plants May Improve Indoor Air Quality

For those of you in the interior plants business, here is some information that you should find interesting and may want to pass along to your customers. I recently read an article about some research conducted on the efficiency of interior plants in the removal of air pollutants from homes and office buildings. Thirty (30) species of house plants were tested for their ability to remove volatile organic chemicals (VOCs) from the air. Of the 30 species observed, Boston fern, pot mum, and dwarf date palm were found to be the most efficient plants at removing VOCs.

Certain items in our homes and offices such as carpeting, furniture, cleaning agents, computers, copying machines, etc. release VOCs into the air. These chemicals are especially strong in new buildings, but many still remain for years. The primary chemicals that were studied are formaldehyde, xylene, and ammonia.

Data from the experiment indicates that both plant leaves and soil micro- organisms are responsible for the removal of VOCs from the air. It is theorized that the foliage absorbs these gases from the air and moves them to the plant roots where they are broken down by the micro-organisms in the soil. The factors that determine a plant's efficiency in removing these pollutants are leaf structures that affect transpiration rates and the plant's ability to culture large numbers of gram negative bacteria around their roots. The plants mentioned above were the top three observed in this experiment. There are others that are also good at removing air pollutants. For more details about this experiment consult "Nursery Notes, January- February, 1994, pages 34-40" or contact me for this information.

Smart Buy Forms Available

In my last issue of this newsletter, I wrote of a computerized database of vegetable growers and buyers that NCDA will be maintaining in order to match NC growers with produce buyers. This system is called "Smart Buy", and I now have application forms if you are interested in being listed on this database.

Potential Aquaculture Farmers Sought

I know this is not a horticultural related topic, however, any of you may be interested in this proposal or you may know of someone who is. Below is the content of a memo sent to county Extension directors from Tom Losordo, Extension Aquaculture Specialist.

Since 1990, the Aquaculture Program at NCSU has been developing and demonstrating technology to grow fish in barns much like poultry or hogs. We now feel that the technology is ready for transfer to the farm for a commercial operation.

To insure that the first two commercial units are successful, the Cooperative Extension Service has received funding from the Department of Commerce to provide a full-time Extension Associate to assist in the construction and start-up of these facilities. The Extension Associate will work on the farm at no cost to the farmer except for travel mileage to and from NCSU.

The Extension Associate will work with the farmer up to eight months. In return, the farmer must make the farm available as an Extension demonstration site.

Depending on the farmer's existing resources (e.g., an existing well, building, and labor to share with this project), the construction and start-up phase of this project will cost between $150,000 and $250,000. The facility will produce approximately 6,000 pounds of Tilapia fish per month. We will assist the farmer in locating a market for the fish prior to construction.

With current market conditions, we predict that the first facility will pay back the start-up money over 15 years at a rate of 7.5% yield an additional return on the investment from 7-10%.

Please contact Dr. Tom Losordo at NCSU for more information at (919) 515-7587.

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Recommendations for the use of chemicals are included in this publication as a convenience to the reader. The use of brand names and any mention of listing of commercial products or services in this publication does not imply endorsement by the North Carolina Cooperative Extension Service nor discrimination against similar products or services not mentioned. Individuals who use chemicals are responsible for ensuring that the intended use complies with current regulations and conforms to the product label. Be sure to obtain current information about usage and examine a current product label before applying any chemical. For assistance, contact an agent of the North Carolina Cooperative Extension Service in your county.

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