Effects of Surface Seals on Pest Control Efficacy with 1,3-Dichloropropene/Chloropicrin

Authors: Hanson, Bradley; Gao, Suduan; SHRESTHA, ANIL - UNIVERSITY OF CALIFORNIA; Gerik, James; Schneider, Sally

Submitted to: International Conference on Methyl Bromide Alternatives and Emissions Reductions
Publication Type: Proceedings
Publication Acceptance Date: 10/26/2007
Publication Date: 11/1/2007
Citation: Hanson, B.D., Gao, S., Shrestha, A., Gerik, J.S., Schneider, S.M. 2007. Effects of Surface Seals on Pest Control Efficacy with 1,3-Dichloropropene/Chloropicrin. International Conference on Methyl Bromide Alternatives and Emissions Reductions.

Interpretive Summary: Soil fumigation has been used for many years for control of soil-borne pests including parasitic nematodes, disease pathogens, and weeds in high value cropping systems. The phase-out of methyl bromide has resulted in increasing use of alternative fumigants such as 1,3-dichloropropene (1,3-D) and chloropicrin. These compounds can have negative human health and environmental consequences related to worker and bystander safety and release of volatile organic compounds (VOC) that contribute to air pollution. Controlling fumigant emissions has become an important goal of regulatory agencies in California and has spurred research on techniques to effectively keep fumigants in the soil and/or to rapidly degrade the compounds before they are released into the atmosphere. This research focuses on evaluations of soil-borne pest control as affected by emission reduction techniques including pre-irrigation, water seals, and additions of potassium thiosulfate (KTS) or composted manure. Preliminary data suggests that the aforementioned emission reduction techniques can have both positive and negative impacts on pest control efficacy; however, additional research is needed to determine more precisely the relationship between effective emission reduction and pest control efficacy under commercial production conditions.

Technical Abstract: Soil fumigation has been used for many years for control of soil-borne pests including parasitic nematodes, disease pathogens, and weeds in high value cropping systems. The phase-out of methyl bromide has resulted in increasing use of alternative fumigants such as 1,3-dichloropropene (1,3-D) and chloropicrin. These compounds can have negative human health and environmental consequences related to worker and bystander safety and release of volatile organic compounds (VOC) that contribute to air pollution. Controlling fumigant emissions has become an important goal of regulatory agencies in California and has spurred research on techniques to effectively keep fumigants in the soil and/or to rapidly degrade the compounds before they are released into the atmosphere. Several soil moisture management techniques and adding chemical or organic amendments have been shown to reduce 1,3-D emissions; however, the effects of these techniques on pest management efficacy is not well documented. This paper will focus on preliminary evaluations of soil-borne pest control as affected by emission reduction techniques. Preliminary data suggests that emission reduction techniques can have both positive and negative impacts on pest control efficacy. For example, nematode control appeared to be reduced at 60 and 90 cm in the soil profile by the wettest soil conditions and by the addition of composted manure. Similarly, the addition of extra water to contain emissions also appeared to reduce effective weed control with 1,3-D. Conversely, the addition of potassium thiosulfate (KTS) appeared to reduced weed emergence and biomass production even in the absence of the fumigant. Additional research is needed to determine more precisely the relationship between effective emission reduction and pest control efficacy under commercial production conditions.