- Vegetables: tomatoes
- Crop Production: high tunnels or hoop houses, shade cloth
This project was designed as an experiment to retrofit existing high tunnel structures used for growing vegetables with a woven shade cloth material. The hypothesis was that the shade cloth could act as an effective bug screen without completely restricting air flow and ventilation. Our farm had an existing high tunnel that we used for the experiment. The results of the study were very promising and we feel that this method has applications in the future of the small farm.
Local Appetite Growers is a small polycultural farm in Baldwin County Alabama - right along the Gulf Coast. Utilizing high tunnel production, field production, and hydroponics our farm grows food crops for the local restaurant and farmers markets. Facing intense insect pressures of the coastal environment, this study was an experiment in a mechanical method of screening pests from valuable food crops grown inside of high tunnel structures. This mechanical screening was achieved using a woven shade cloth material retrofitted to existing high tunnel structures. The results of the study were promising for the use of this material and methodology as a way to reduce the use of pesticides in vegetable production in the South.
Insect pressure is one of the major challenges of vegetable production in the deep south. Heavy and repeated applications of pesticides are not only expensive and time consuming to the farmer, but is also much less desirable by the end consumers and the environment. Fresh market produce is expected to be visually blemish free with insect damaged produce fetching a lower price or not selling at all. This is a challenge to growers in the Gulf Coastal South where bug pressure starts early in the Spring and persists late into the Fall because of warm weather and plentiful moisture - many insects have another entire life cycle along the Gulf coast than those just a few hours inland.
Seeking an alternative to repeated pesticide applications, this project sought a method of mechanical exclusion of insects inside of an existing high tunnel. After researching net houses and screen houses, it was deemed that most bug screens available were limited in that there was a major reduction in airflow inside of the structure because of the fine mesh of the bug screens. Heat and humidity buildup inside of these structures was a major issue, and often led to disease, fungus, and mold outbreaks. Realizing that for the crops that our farm produces were mainly affected by larger body insects including moth caterpillars, stink bugs, leaf-footed bugs, and the various cucumber beetles and other beetles - we sought a material for screening that would exclude the larger body insects but still allow for adequate airflow and passive ventilation.
The idea for using woven shade cloth as a bug screen started to seem possible. We had noticed the effectiveness of the shade cloth as a bug screen on one of our tunnels by accident. We had an oversized piece of shade cloth with the extra portion hanging along the west wall of the high tunnel (adjacent to the roll up side walls). We noticed leaf footed bugs piling up on the outside of the shade cloth trying to get to the crops inside. The idea of a hybird high tunnel was born. We used our existing high tunnel and fitted a 50% woven shade cloth to the endwalls and sidewalls between the base boards and the hip boards of the structure.
For this study we proposed growing Spring season tomatoes on the inside of the structure versus a control crop of tomatoes grown on the outside of the structure. For the Fall season we used sugar snap peas as our test crop.
The objective of this study was to test the use of woven shade cloth for a bug screen material in simple high tunnel growing structures. With the intense insect pressure along the Gulf Coast, regular pesticide application is necessary to produce quality vegetable crops for market. This is an expensive, time consuming and environmentally questionable practice. We sought to try to reduce pesiticide usage by the use of mechanical screening system.
Similar net house studies have been performed but many of the studies used fine meshed bug screening products that severely limited airflow and ventilation. Traditional bug screening products are designed with small mesh size to exclude all small bodied insects including whiteflies and thrips. Since our target insects were larger body insects such as moths, stink bugs, squash bugs, and various beetles - we felt that the use of a larger meshed materials would help to solve the problem of airflow and ventilation.