2012 Annual Report
1a.Objectives (from AD-416):
Objective 1: Determine the effect of temperature and reproductive state on susceptibility of tarnished plant bugs to Beauveria (B.) bassiana (ARSEF 8889).
Objective 2: Determine the effect of exposure to insect growth regulators (IGRs) and B. bassiana (ARSEF 8889) on immature tarnished plant bug survival.
Objective 3: Determine the effect of host plant and application timing (season) on susceptibility of tarnished plant bugs treated with ARSEF 8889 and IGRs (in situ).
1b.Approach (from AD-416):
The effect of temperature and reproductive state on the susceptibility of tarnished plant bugs to Beauveria (B.) bassiana (ARSEF 8889) will be determined in replicated laboratory tests. The two reproductive states tested will be normal reproductive adults and nymphs and diapausing adults and nymphs that produce diapausing adults. Temperatures tested will range from 10°C to 30°C. Insect growth regulators (IGRs) will be tested with nymphs in replicated laboratory tests to determine which IGRs are effective and the rate at which to use them. The most effective IGR(s) will be tested in laboratory tests in combination with ARSEF 8889 to determine the most effective combination treatment. Results from the laboratory tests will be tested in the field in replicated tests in cotton (for in-season plant bug control) and in the fall and winter on wild host plants (for control of the diapausing overwintering generation). The effect of IGRs and ARSEF 8889 treatment on beneficial arthropod populations will be evaluated in the field tests and with additional laboratory tests.
ARSEF 8889 was evaluated for tarnished plant bug (TPB) control in cotton in 2011. The test was conducted under extreme conditions in that the temperature exceeded 90°F on every day of the test and the TPB population in the cotton was well established and above the treatment threshold in every plot when the test began. None of the treatments controlled the TPB population including a standard treatment with dicrotophos or acephate (tests with a glass-vial bioassay showed that the population was highly resistant to pyrethroid and organophosphate insecticides). The test will be repeated in 2012 and will be changed so that the first treatment application is made earlier when below threshold numbers are present. A second application will be made one week after the first application. Deposition of spores on different locations in the plants will also be determined and used to evaluate spray coverage and residual effectiveness for TPB control. A field test using ARSEF 8889 to control TPB in corn when it tassels and in soybeans during bloom will be conducted. Field tests in the fall to evaluate the use of ARSEF 8889 and novaluron for control of overwintering TPB on wild hosts will again be conducted In a cooperative effort between SIMRU and the Boyce Thompson Institute, the genome of Beauveria bassiana has been sequenced and will be published this year.
Bioassay procedure. A bioassay procedure was established to measure Beauveria (B.) bassiana mortality and infection levels from residual contact of Tarnished Plant Bugs (TPB) with treated cotton leaves. ARS scientist in the Southern Insect Management Research Unit at Stoneville, MS, are studying B. bassiana as a control for the TSB. This procedure is a tool to be used in the continue study of B. bassiana. There is no significant impact U.S. agriculture problems.
Portilla, M., Snodgrass, G.L., Streett, D. 2011. Effect of modification of the NI artificial diet on the biological fitness parameters of mass reared Western Tarnished Plant Bug, Lygus hesperus. Journal of Insect Science. 11:149. doi:10.1673/031.011.14901.
Ugine, T.A. 2012. Developmental time and age-specific life tables for Lygus lineolaris (Heteroptera: Miridae). Environmental Entomology. 41(1):1-10. http://dx.doi.org/10.1603/EN10210.