Location: Water Management ResearchTitle: Fumigation efficacy and emission reduction using low-permeability film in orchard soil fumigation
|Hanson, B - University Of California|
|Cabrera, J - University Of California|
|Sosnoskie, L - University Of California|
|Qin, R - University Of California|
|Thomas, J - University Of Florida|
Submitted to: Pest Management Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/10/2015
Publication Date: 3/26/2015
Citation: Gao, S., Hanson, B.D., Cabrera, J.A., Sosnoskie, L., Qin, R., Gerik, J.S., Wang, D., Browne, G.T., Thomas, J. 2015. Fumigation efficacy and emission reduction using low-permeability film in orchard soil fumigation. Pest Management Science. doi: 10.1002/ps.3993.
Interpretive Summary: Control of pests especially nematodes in perennial crop fields is a challenge because of the less efficacious alternative fumigants to methyl bromide and fumigant emissions that increase exposure risks. This research evaluated the effects of tarping with a totally impermeable film (TIF) in conjunction with the use of reduced rates and a carbonation technique on fumigant emissions, distribution in soil, and control of nematodes, pathogens, and weeds in a field trial. The results clearly show that the TIF can significantly reduce emissions by retaining fumigants under the tarp and has a potential to use lower rates. The carbonation technique that potentially enhances fumigant dispersion to improve pest control in deep soil needs to be optimized by determining specific conditions required. This research continues in the effort to increase fumigation efficiency while minimizing emissions.
Technical Abstract: BACKGROUND: Many orchards in California, USA, apply fumigants to soil before replanting to reduce the impact of pest pressure or replanting disease on new tree establishment. Emission control of alternative fumigants to methyl bromide is mandatory in air quality (ozone) non-attainment areas. This study assessed tarping with VaporSafe™ TIF (totally impermeable film) to minimize emissions, improve pest control efficiency, and reduce fumigant application rate in the field. A field trial was conducted to evaluate different tarps, full and reduced rates, and a carbonation technique to treat fumigant product Telone® C35. RESULTS: All fumigated treatments at 2/3 or full rates regardless of tarp type provided good nematode control above 100 cm soil depth, but significant survival was found at the lower soil depths. Large variation in pathogen control was observed among species. Weed recovery was lower in tarped and higher application rates than non-tarped and lower rates. There were no significant differences on pest control between carbonation and non-carbonation of fumigants. The TIF reduced total emissions >95% relative to non-tarped soil while standard polyethylene (PE) tarp reduced ~30%. Emissions near TIF tarp-edges were low from the deep shank application commonly used in perennial fields. CONCLUSION: Carbonation of fumigant under 207 kPa did not improve fumigant dispersion for better efficacy. Reduced 2/3 rate under TIF showed nematode control as effective as full rate in bare soil or under standard tarp. However, soil fumigation still faces a great challenge for effective control of nematodes in deeper soil that needs to be continuosly addressed for perennial crops.