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ARS Home » Southeast Area » Stoneville, Mississippi » Southern Insect Management Research » Research » Publications at this Location » Publication #172130
Title: CHARACTERISTICS OF BEAUVERIA BASSIANA ISOLATES FROM LYGUS LINEOLARIS POPULATIONS OF MISSISSIPPI

Author
item Leland, Jarrod

Submitted to: Journal of Agricultural and Urban Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/20/2005
Publication Date: 4/1/2005
Citation: Leland, J.E. 2005. Characteristics of beauveria bassiana isolates from lygus lineolaris populations of mississippi. Journal of Agricultural and Urban Entomology.

Interpretive Summary: Fungi may provide a much needed option for controlling tarnished plant bugs. Strains of fungi from populations of tarnished plant bugs native to cotton growing regions may be better adapted to controlling these populations. Nineteen strains of the fungus (Beauveria bassiana) collected from tarnished plant bugs in Mississippi were evaluated for characteristics relevant to production and commercial development. Characteristics included lethality to tarnished plant bugs, potential for producing spores on growth media, survival under artificial sunlight, and ability to germinate at high temperatures (35 °C). Comparisons were made among these nineteen strains, a strain from a tarnished plant bug from Arkansas and a strain used in a commercial product (GHA). Eleven of the strains from tarnished plant bug caused significantly higher mortality and several caused ten time more mortality in tarnished plant bug adults. The strains from tarnished plant bug also killed faster than the commercial strain. Strains generally produced spore concentrations on growth media similar to or greater than the commercial strain. All isolates were highly susceptible to artificial sunlight. One strain from a tarnished plant bug in MS germinated at 35°C and all others exhibited little or no germination. These laboratory studies indicate that strains from tarnished plant bugs may be used to improve commercial products particularly if they can be protected from sunlight through formulation and application strategies.

Technical Abstract: Beauveria bassiana (Balsamo) may provide a much needed option for control of Lygus lineolaris (Palisot de Beauvois). Fungal isolates from L. lineolaris populations native to cotton growing regions may be better adapted for controlling these populations. Nineteen B. bassiana isolates from L. lineolaris in Mississippi were evaluated for characteristics relevant to production and efficacy of a mycoinsecticide for Lygus control. Characteristics included pathogenicity to L. lineolaris adults, in vitro conidia production, tolerance to artificial sunlight, and germination at 35 °C. Comparisons were made among these nineteen isolates, a B. bassiana isolate from L. lineolaris in Arkansas (ARSEF 3769), and a commercial B. bassiana isolate (GHA). Eleven of the isolates from L. lineolaris were significantly more pathogenic than GHA based on LC50 values, with several having LC50 values over ten times lower than GHA. The higher pathogenicity of these isolates was also reflected in lower LT50 values and higher sporulation of cadavers, particularly at intermediate conidia concentrations. Isolates from L. lineolaris were generally prolific conidia producers, producing conidia concentrations on barley agar similar to or greater than GHA. All isolates were highly susceptible to the negative effects of artificial sunlight. One isolate from L. lineolaris in MS germinated at 35°C and all others exhibited little or no germination. These laboratory studies indicate that isolates from L. lineolaris may improve mycoinsectide efficacy through higher pathogenicity, particularly if the negative effects of solar radiation and high temperatures could be mitigated by formulation or application strategies.