Difference between revisions of "BioControl (2014) 59, 111-123"

Revision as of 18:15, 30 May 2014

Gabriel Moura Mascarin, Nilce Naomi Kobori, Eliane Dias Quintela, Steven Paul Arthurs and Ítalo Delalibera Júnior (2014)
Toxicity of non-ionic surfactants and interactions with fungal entomopathogens toward Bemisia tabaci biotype B
BioControl 59 (1), 111-123
Abstract: Several non-ionic surfactants can be used to enhance insecticidal performance of various bio-based products and agrochemicals. In this study, we describe the toxicity of four commercial non-ionic surfactants against immature Bemisia tabaci (Gennadius) biotype B whiteflies along with their spreading ability. Results revealed that trisiloxane-based surfactants (Break-thru^® and Silwet^® L-77) exhibited the highest toxicity to 1st-2nd (early) and 3rd-4th (late) instar nymphs as well as the greatest wetting performance. We also investigated whether sub-lethal concentrations of Break-thru^® and Silwet^® L-77 improved the insecticidal efficacy of the fungal entomopathogens Beauveria bassiana (Balsamo) Vuillemin (strain CG1229) and Isaria fumosorosea Wise (strain CG1228) conidial suspensions against whiteflies. Germination of hydrophobic conidia of both isolates were unaffected by these surfactants over the range 100-1000 ppm. The combinations of both fungi with trisiloxane carriers significantly increased nymphal mortality with mostly additive and synergistic effects on early and late nymphs, respectively. In screenhouse trials, both fungi (10⁷ conidia ml^-1) mixed with 200 ppm of Silwet^® L-77 significantly improved effectiveness against early nymphs (72-74 % mortality) compared with controls treated with water and Silwet^® L-77 alone. In addition, reduced volume rates of I. fumosorosea in Silwet^® L-77 (equivalent to 100 l ha^-1) were at least as effective against late nymphs as higher volume rates (200 l ha^-1) at equivalent conidial doses. Our findings underline the compatibility and enhanced activity of silicon-based surfactants with B. bassiana and I. fumosorosea for use in integrated whitefly management programs.
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Link to article at publishers website
Database assignments for author(s): Steven Arthurs

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
formulation/storage of bioagents

Pest and/or beneficial records: