Control information for the desert subterranean termite Heterotermes aureus (Snyder) (Isoptera: Rhinotermitidae) is limited, despite being one of three major termite pests in the United States. Annual control information comes from field evaluations by the USDA–Forest Service. This partial assessment of termiticide efficacy is likely deficient without concurrent residual analysis and laboratory bioassays of termiticides. In this study, six termiticides were evaluated using exposed and covered field plots in Tucson, AZ, over a 5-yr period for persistence and efficacy by using both residue analysis and laboratory bioassays. All the termiticides degraded significantly during the study. Termiticide degradation seemed to be consistently slower in covered plots than in exposed plots, although this trend was not statistically supported. A comparison of yearly degradation rates showed the three classes of termiticides degraded at different rates. Chlorpyrifos, the organophosphate, degraded quickest at a rate of 68.9% for each doubling of time, whereas chloronicotinyls and pyrethroids degraded at much slower rates (50.4 and 48.4% for each doubling of time, respectively). Bioassays showed termites tunneled 1.26 ± 0.61 cm deeper in uncovered plots than in those that were covered. Mortality rates in bioassays from covered treatments were 16.13 ± 9.87% higher than in uncovered treatments. Our study demonstrated that the termiticides evaluated could remain effective against H. aureus for at least 4 yr after application, particularly under covered conditions. Additionally, it is anticipated that retreatments may be necessary before the 5-yr warranty expires when using final grade applications to stem walls in warmer parts of Arizona.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 99 • No. 4