Simulated Field Evaluation of Six Techniques for Controlling the

Nonchemical and chemical methods for control of drywood termites were evaluated under simulated field conditions. Specifically, we assessed the efficacy of four methods currently marketed as alternatives to whole-structure fumigation for control of drywood termites: excessive heat, excessive cold, electrocution, and microwaves. In addition, we evaluated a reduced dosage of methyl bromide synergized with carbon dioxide, as well as a standard fumigation treatment with sulfuryl fluoride. Tests were conducted using Incisitermes minor (Hagen) in artificially infested or naturally infested boards of various dimensions used in construction. Infested boards were placed into the attic, drywalls, or subarea of the Villa Termiti, a symmetrical building constructed specifically for these tests. Commercial pest control operators performed 5 of the 6 control methods; liquid nitrogen was applied by University of California personnel. For artificially infested boards, mortality was measured 3-d and 4-wk post-treatment. For naturally infested boards, mortality was evaluated only 4-wk post-treatment. Efficacy performance of all treatments was compared to 90, 95, and 99 percent levels of mortality. Termite mortality in artificial boards was 100 percent at 3-d and 4-wk post-treatment for both fumigant gases. Heating the whole-structure or spot-applications using microwaves resulted in 96 and 90 percent mortality, respectively, 3-d post-treatment. Mortality levels 4-wk post-treatment increased to 98 percent for heating and 92 percent for microwaves. Spotapplications of liquid nitrogen at the [email protected] kg/min dose (highest dose tested) achieved 100 percent mortality 3-d post-treatment. However, for the 15-min@ 0.9 kg/min and 7-min@ 0.9 kg/min dosages, 4-wk post-treatment mortality levels were 99 percent and 87 percent, respectively. Mortality by electrocution of termites in artificially infested boards was 44 percent 3-d post-treatment in the first test. Four-weeks post-treatment drywood termite mortality increased to 82 percent. In a second electrocution test, using spot-application techniques infrequently used in structures, mortality levels increased to 93 percent 3-d and 98 percent 4-wk post-treatment.