2012 Annual Report
1a.Objectives (from AD-416):
Demonstrate that using low permeability tarps (e.g., TIF) can improve efficacy while controlling emissions and can be potentially used with lower rates.
1b.Approach (from AD-416):
Two field trials will be conducted to collect soil fumigant (1,3-D, chloropicrin and methyl iodide) and pest control (nematode, pathogen, and weed) data under TIF tarps. Fields with naturally occurring nematode and pathogen populations will be selected. Treatments (4 replicates) will include: control (no fumigation), full rate (maximum allowed) in bare soil, under standard tarp, and TIF tarp, and reduced rates (2/3 and 1/2 of full rate) under TIF. Soil-gas concentrations will be monitored at pest sampling locations and depths. Correlation between fumigant dosage and pest control, and treatment effects will be statistically analyzed. Tarp permeability will be measured before and after installation. Fumigant change in the air under tarp will be monitored to estimate the proper time for the safe removal of TIF tarps to minimize exposure risks, a major concern of regulatory agencies. Almond trees will be planted the following spring and tree responses to treatments will be monitored.
This project supports objective 3 of the parent project. The objective of the project is to demonstrate that using totally impermeable film (TIF) will improve efficacy and can be potentially used with lower fumigant rates in orchard replanting field. This project is in collaboration with University of California Cooperative Extension farm adviser in Merced County, CA. From a field trial conducted in October-November 2011, in combination with another project, necessary information for this project was collected including emission and fumigant transport as well as efficacy at reduced Telone C35 rates at 2/3 or 1/3 under TIF in comparison with the full rate under bare soil or standard tarp. The results indicate that the 1/3 rate under TIF was too low to provide good control on parasitic nematodes in soil especially at deeper depths. This information is being used to modify the treatments in the next field trial, i.e., half rate will be the lowest rate for testing.