2013 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 and novaluron (Diamond) used alone and in combination were evaluated for control of tarnished plant bugs in large (ca. 1 acre) replicated plots of cotton at Stoneville, MS, in June and July 2012. ARSEF 8889 (>8 trillion spores/ acre) used in combination with novaluron (9 oz/acre) was as good as standard insecticides (acephate 1 lb AI/acre, sulfoxaflur 2.5 oz/acre) in reducing numbers of tarnished plant bug adults and nymphs in the cotton. The combination treatment had the highest yield of cotton in the test and had a much smaller impact on beneficial arthropods than the standard insecticide treatment. The high rate of ARSEF 8889 used in the experiment is cost prohibitive for use in normal cotton production. Laboratory studies showed that ARSEF 8889 was more effective than Beauveria bassiana Strain GHA at low temperatures against plant bugs and could be used to control plant bugs on weeds in the fall and winter. The effectiveness of ARSEF 8889 for plant bug control in cotton is being tested by combining its spores with a new surfactant (Bio-plastic) which might protect the spores from Ultraviolet radiation. Studies are again being conducted to determine deposition patterns for spores of ARSEF 8889 sprayed on cotton and infection rates for plant bugs found on different plant parts.
Ugine, T.A. 2011. The effect of temperature and exposure to Beauveria bassiana on tarnished plant bugs Lygus lineolaris (Heteroptera: Miridae) population dynamics and the broader implications of treating insects with entomopathogenic fungi. Biological Control. 59(3):373-383.