Soil Solarization in Combination with Reduced–Rate Fumigation for Pest Control.

The concern of potentially adverse environmental risks of soil fumigants has led investigators to study reduced-chemical pest control methods. Soil solarization has been proposed as an alternative to soil fumigants. However, this technology has not been widely adopted mainly because of insufficient pest control efficacy. The objective of this study was to determine the combined effects of fumigant and solarization on soil-borne pest control in a field site. A reduced-rate of 70% Inline (1, 3-D, chloropicrin) was applied with drip irrigation to raised soil beds covered with high-density polyethylene film, thermic film, and virtually impermeable film.  Temperatures within the beds were monitored using thermocouples connected to a datalogger. The spatio-temporal variation in the soil gas concentration was measured to determine the concentration-time index (CT). The efficacy of pest control of various treatments was monitored using bioassay muslin bags containing soil infested with citrus nematodes (Tylenchulus semipenetrans). Compared to the standard high-density polyethylene film, nematode control efficacy was improved in soils covered with thermic film and virtually impermeable film because of the enhanced soil temperature and fumigant concentration. The information obtained from this study is useful for the development of feasible soil disinfestation methods that reduce reliance on fumigants and are more environmentally benign.