Location: Water Management Research
Title: Using TIF tarp and reduced fumigation rates for almond replanting Author
Submitted to: Extension Reports
Publication Type: Other
Publication Acceptance Date: November 1, 2013
Publication Date: December 3, 2013
Citation: Gao, S. 2013. Using TIF tarp and reduced fumigation rates for almond replanting. 2012-2013 Annual Reports CD-ROM. Modesto, California: Almond Board of California. Technical Abstract: Almond replanting still relies on pre-plant soil fumigation to control soil-borne pests and diseases in order to establish productive and healthy trees. With the environmental constraints on fumigant use, fumigation methods for high pest control efficiency and low emissions are needed greatly. In late fall of 2012, a fumigation field trial was conducted in an almond orchard that was scheduled to be replanted in Merced County. The field had a high nematode population, chiefly pin nematodes and some ring nematodes. This trial was designed to test if low permeability tarps such as totally impermeable film (TIF) can improve efficacy and potentially reduce emissions when using reduced rates. Fumigation treatments included non-fumigated control, three rates (full or maximum allowed label rate, 2/3, and 1/3 of Telone® C-35), and three surface sealing methods (bare, standard polyethylene (PE) tarp, and TIF) with six replicates in a randomized complete block design. Emissions, gaseous fumigant concentration under the tarp, and fumigant concentrations in soil profile were determined for about five weeks. Both soil existing indigenous nematodes and bioassay bags containing soils infested with citrus nematodes were investigated for treatment efficacy. This trial emission data illustrated again that TIF tarp can significantly reduce emission peak flux compared to the standard PE tarp due to the ability of TIF to retain fumigants. All full rate treatments and the 2/3 rate under TIF provided 100% kill for resident nematodes in the top soil above 1 m depth. In soil below 1 m, however, all treatments including the full rate under TIF showed survival of nematodes. Thus controlling nematodes at deep soil depths continues to be a challenging task in replanting orchards.