Strawberry

Pesticide Safety and Management

Consumer consciousness of pesticide use in farming is a major grower concern. Surveys have shown that as much as 80% of the population is concerned about pesticide safety on the food products they buy. U-pick operations can imply freshness, quality and consumer-buying confidence when consumers can meet growers and be assured that their pesticide practices are safe.

Growers will be faced with increased public pressure to control and minimize the use of pesticides in crop production. Alternative management techniques will be necessary to strengthen consumer confidence. Growers should also help dispel misinformation about pesticide residues. For example, it is estimated that the average American citizen is exposed to 46 micrograms of potentially carcinogenic pesticide residues in food and water daily, while a single cup of coffee contains about 500 micrograms of potential carcinogens.

Consider the following factors when selecting pesticides for crop management.

Toxicity of the Chemicals

Chemicals with high LD 50 ratings are less hazardous to the grower and the environment. For example malathion, which has a LD 50 rating of 1200, is not as toxic as guthion, which has a LD rating of 7. Use only chemicals registered for use on strawberries and follow label specifications for rates, days to harvest waiting periods and other conditions. Failure to follow this basic rule of pesticide safety exposes the grower and industry to undue liability and increases the risk to the consumer.

Proper Safety Equipment

Protective devices such as approved gloves, a recommended respirator and approved clothing should be used when handling pesticides. Insecticides can enter the body through the mouth (orally), through the skin (dermally), or through the lungs (respiratory system).

Poisoning

Know what to do in the event of a spill or accidental poisoning. Review procedures on the container label before handling a pesticide. Safe storage and disposal of containers and unused material is important to protect children of U-Pick customers from accidental exposure.

Chemical Application

Pesticide application through the irrigation system is not recommended because coverage is not efficient. As well, there is danger of water supply contamination because irrigation water containing pesticide can flow back into the water source if mainline pressure drops suddenly. Contamination by back siphoning can be avoided by using a reduced pressure back-flow preventer. This device is installed in the supply line at a point well ahead of the material injection point. Similar precautions to control back-flows should be observed when filling sprayers from lakes, rivers or streams.

NOTE: Before installing this unit, consult the water authorities regarding local regulations.

Observe the waiting period specified on the label before entering treated fields. If the waiting period is not observed, chemicals on the foliage can be absorbed through workers' skin or lungs.

Spraying Effectiveness

Several factors influence the effectiveness of pesticide application. These include correct diagnosis of the problem, appropriate spray intervals, resistance of the pest and weather conditions. A water pH of 8 or more can also affect the efficiency of certain pesticides.

High spray pressure is essential for full coverage of the large foliage area of a strawberry row. Pesticides must be applied in at least 100 gal./acre (1123 L/ha) of water at a pressure of 200 psi (1379 kPa). Field sprayers with low volume and pressure capability are not suitable for spraying insecticides and fungicides on strawberry crops.

For greater coverage, use a chain ruffler rather than a solid bar. Nozzles should be set to a point slightly forward so material is applied immediately behind rather than in front of the chain. This nozzle position will provide increased coverage of the upper leaf surface and twice the coverage of the underside.