Solarization

 Solarization requires the trapping of heat under a transparent polyethylene tarp, to raise

 soil temperatures high enough to prove lethal to plant pathogens and pests in the soil (Devay,

 1991b). Soil solarization has been found to be effective in the control of nematodes (Lamberti

 and Greco, 1991) and (Satour et al., 1991) weeds (Abu-Imailech, 1991), and fungi and bacteria

 (Devay, 1991a). However, for effective control, this method is dependent on several factors,

 such as temperature and moisture.

 This method is most effective when practiced during the warmest part of the year, with

 bright sunny days for 4 to 8 weeks raising soil temperatures to lethal levels for control of

 nematodes (Heald, 1987). Soil moisture is important in this treatment for maximum heat

 transfer to soilbore organisms and reduction of evaporative heat loss, providing a greenhouse

 effect (Noling, 1992). Other factors that influence the effectiveness of solarization include air

 temperature, length of day, sunlight intensity, and thickness and light transmittance of the plastic

 being used (Devay, 1991b).

 In Florida however, the hottest part of the year experiences cloud cover with heavy

 rainfall. Thus, water collects on the surface of the plastic, resulting in heating the water instead

 of the soil. Another problem with solarization as a non-chemical alternative to methyl bromide

 use is that much of the soil is of the sandy type in vegetable producing regions of Florida.

 These soils drain well and do not retain moisture, which is required for effective transfer of heat

 to soilborne organisms (Noling, 1992). Soil solarization is ineffective in the control of nutsedge,

 which is a major weed problem in certain regions of Florida. Other considerations when using

plastic for solarization are the longevity and disposal of the plastic. The integrity of the plastic