Mary E. Barbercheck, Penn State University
Methods in this category use some physical component of the environment—for example, temperature, humidity, or light—to suppress pest populations or damage. Some examples of physical and mechanical pest controls include:
- soil solarization or soil heating
- row covers
Tillage can help minimize damage from soil-dwelling insects by directly killing the insect, exposing insects to predation by birds or other predators, and by helping the plant grow more rapidly (this is not a guaranteed outcome). The principle behind this approach is that the sun will warm up the soil around the plants faster and allow them to outgrow the pest’s feeding.
Heat or steam sterilization of soil is commonly used in greenhouses for control of soil-borne pests and diseases. In soil solarization, clear plastic mulch is applied to bare soil for an extended period of time (4–6 weeks) during the warmest, sunniest time of year to disinfest soil. The clear plastic allows the sun’s energy to heat the soil below to temperatures over 100°F. This method is not selective, so heat sensitive beneficial organisms will also be destroyed.
Floating row covers over vegetable crops exclude many pests. The edges and ends of the row covers should be completely sealed to the ground to effectively prevent the entry of pest insects. When using floating row covers, timing of removal of row covers for access by pollinators and for weeding must be considered.
Altieri, M., C. I. Nichols, and M. A. Fritz. 2005. Manage insects on your farm: A guide to ecological strategies. Sustainable agriculture network handbook series book 7. (Available online at: http://www.sare.org/Learning-Center/Books/Manage-Insects-on-Your-Farm) (verified 25 April 2011).