Historical review of termite activity at forest service termiticide test sites from 1971 to 2004.

The U.S. Forest Service has a long history of providing termiticide efficacy data used for product registration and labeling. Four primary test sites (Arizona and Florida, Mississippi, and South Carolina [hereafter southeast]) have been used for this purpose. Various parameters of termite attack at water-only control plots were examined in this study to assess the relative pressures of termites at each site. Termiticide studies installed between 1971 and 2001 by using ground board (GB) and concrete slab (CS) test methods were included. GB control plots were attacked 85% of the time in the southeast, about twice the rate observed in Arizona (43%). CS plots were attacked 59-70% of the time in the southeast, significantly higher than in Arizona (43%). Termites were slower to initiate attack at control plots in Arizona compared with the southeast, and they were up to twice as slow at GB controls. Once initial attack began, GB plots were reattacked at higher percentages in the southeast (89-90%) than in Arizona (67%). Reattack at CS plots ranged from 65% in Arizona and South Carolina to 76% in Mississippi. Termites caused less damage to wooden blocks in control plots in Arizona than the southeast. Attack rates at controls generally declined during the 1990s, but these rates have rebounded since 2000, except at CS plots in Arizona and South Carolina. Statistical analysis of attacks at plots treated with chlorpyrifos, cypermethrin, fenvalerate, and permethrin also was undertaken. Time to initial termite attack (failure) of the organophosphate chlorpyrifos was generally shorter in Arizona than in the southeast, whereas time to initial attack in plots treated with one of three pyrethroids (cypermethrin, fenvalerate, and permethrin) was generally longer in Arizona.

Persistence and efficacy of termiticides used in preconstruction treatments to soil in Mississippi.

Laboratory and field studies were conducted to determine the persistence and efficacy of termiticides used as preconstruction treatments against subterranean termites. Bifenthrin (0.067%), chlorpyrifos (0.75%), and imidacloprid (0.05%) ([AI]; wt:wt) were applied to soil beneath a monolithic concrete slab at their minimum labeled rates. Soil samples were taken from three depths (0-2.5, 2.6-7.6, and 7.7-15.2 cm) at six sampling times (0, 3, 6, 9, 12 and 48 mo) from sites in Harrison and Oktibbeha counties in Mississippi. Residue analyses were conducted on the 0-2.5- and 2.6-7.5-cm depths, and bioassays were conducted using all three depths. In field studies, significant termiticide degradation occurred between sampling times 0 and 48 mo for all termiticides. At all sampling times, the top 2.5 cm of soil contained more termiticide than the other depths. Time to 50% dissipation of termiticide in the 0-2.5-cm depth was 9, 6, and 2 mo for bifenthrin, chlorpyrifos, and imidacloprid, respectively. Termite mortalities in contact bioassays remained high for bifenthrin and chlorpyrifos throughout the 48-mo sampling period; however, mortality of termites exposed to imidacloprid-treated soil dropped after the initial sampling. Termites readily penetrated all termiticide-treated soil in bioassays of 52-mm soil cores at 48 mo. Percentage of mortality in these bioassays was 15, 43, and 13 for bifenthrin, chlorpyrifos, and imidacloprid respectively.

Effect of selected insecticides on the natural enemies Coleomegilla maculata and Hippodamia convergens (Coleoptera: Coccinellidae), Geocoris punctipes (Hemiptera: Lygaeidae), and Bracon mellitor, Cardiochiles nigriceps, and Cotesia marginiventris (Hymenoptera: Braconidae) in cotton.

We evaluated the toxicity of three insecticides (lambda cyhalothrin, spinosad, and S-1812) to the natural enemies Bracon mellitor Say, Cardiochiles nigriceps Viereck, Coleomegilla maculata De Geer, Cotesia marginiventris (Cresson), Geocoris punctipes (Say), and Hippodamia convergens Guérin-Méneville, in topical, residual, and field assays. Lambda cyhalothrin exhibited the greatest toxicity to the natural enemies. In topical toxicity tests, lambda cyhalothrin adversely affected each natural enemy species studied. Residues of lambda cyhalothrin on cotton leaves were toxic to B. mellitor, C. nigriceps, C. maculata, and C. punctipes. Interestingly, residues of this insecticide were not very toxic to C. marginiventris and H. convergens. Geocoris punctipes and C. maculata numbers in the field generally were significantly lower for lambda cyhalothrin treatments than for the other four treatments, substantiating the previous tests. Although cotton aphids began to increase over all treatments around the middle of the test period, the number of cotton aphids in the lambda cyhalothrin plots was significantly higher than the number in any of the other treatments. As cotton aphids increased in lambda cyhalothrin field plots, the predator H. convergens also increased in number, indicating that lambda cyhalothrin did not adversely affect it in accordance with the residual tests. Spinosad exhibited marginal to excellent selectivity, but was highly toxic to each parasitoid species and G. punctipes in topical toxicity tests and to B. mellitor in residual tests. Spinosad generally did not affect the number of G. punctipes, H. convergens, and C. maculata in the field except for one day after the second application for G. punctipes. S-1812 exhibited good to excellent selectivity to the natural enemies. Some reduction of G. punctipes occurred for only a short period after the first and second application of this insecticide in the field. H. convergens and C. maculata were affected very little by S-1812.