Principles of Integrated Pest Management

Integrated pest management (IPM) is the ecological approach to pest control. It uses ALL suitable techniques to reduce pests below economic levels. It is not the intention of IPM to do away with chemicals. If anything, IPM is designed to protect chemicals from being lost or becoming ineffective. When insect pest populations reach economic threshold levels, control measures must be taken. The ultimate line of defense against insect enemies is the use of chemicals. These control costs can be very expensive, but the cost of not controlling could be total crop destruction. With IPM, when chemicals are used, it is because they are necessary; facts replace hunches.

IPM is needed even in high cash crops such as tobacco. Indiscriminate use of insecticides destroys beneficial insects. This can cause minor or secondary pests to become major pests and major pests to reach serious levels earlier. Overuse of insecticides may also contribute to a resistance buildup by the pests and make control even harder.

Natural Control - This includes weather, beneficial insects, diseases, etc., and results in the death of most insect pests (sometimes as many as 95-97%). Perhaps as many as 50%, or even more, of the potential insect pests are destroyed by beneficial insects before they can do much damage to tobacco. Beneficial insects are very important.

Economic Threshold - This is a level at which a treatment would be profitable and a decision to treat should be made. Economic thresholds may be affected by such things as location, size of insects, presence of beneficials, time of growing season, stage of growth, and the size and condition of the tobacco plant. Economic thresholds are continually changing. When in doubt, consult with your county extension agent.

Tobacco budworms - Treat when four or more plants out of 100 (4%) are infested with budworms during the first 4 weeks after transplanting. After the fourth week and until plantshave buttoned, treat when 10 or more plants out of 100 (10%) are infested. When using CU-263, you may be able to wait a little longer before treatment.

Tobacco hornworms - Treat when 10 or more worms (without parasite cocoons) are found per 100 plants (10%). Worms having white parasite cocoons eat much less, and more of these can be tolerated before treatment is required.

Aphids - Treat when 10% of the plants checked have 50 or more live aphids on at least one leaf.

Flea beetles - Treat when there is an average of three flea beetles per plant early in the season,when the tobacco is small, or an average of 20 flea beetles per plant late in the season, when the tobacco is large. Flea beetles are normally a problem only early in the season (shortly after transplanting) and late in the season (when the harvest of lower leaves moves the flea beetles up the stalk).

Cutworms - Treat when 10% of the plants checked show cutworm damage.

Scouting - Scouting tobacco for various pests was part of the Tobacco IPM program that began in Dillon County in 1979. The program expanded to Florence and Horry counties in 1982 and to Marion County in 1983. Private scouting began in 1984, and continues. Ultimately, we hope that all tobacco in this state will be scouted at least once a week for all crop pests, by trained scouts or by the growers.

For more information, contact Francis P. F. Reay-Jones, 843-662-3526, ext. 208, freayjo@clemson.edu.