Activity of Flonicamid and Two Neonicotinoid Insecticides against Bemisia tabaci (Gennadius) and Its Associated Predators on Cotton Plants

AbstractLaboratory bioassays were carried out with four neonicotinoid insecticides on multiple strains of Bemisia tabaci (Gennadius) to evaluate resistance and cross-resistance patterns. Three imidacloprid-resistant strains and field populations from three different locations in the southwestern USA were compared in systemic uptake bioassays with acetamiprid, dinotefuran, imidacloprid and thiamethoxam. An imidacloprid-resistant strain (IM-R) with 120-fold resistance originally collected from Imperial Valley, California, did not show cross-resistance to acetamiprid, dinotefuran or thiamethoxam. The Guatemala-resistant strain (GU-R) that was also highly resistant to imidacloprid (RR = 109-fold) showed low levels of cross-resistance when bioassayed with acetamiprid and thiamethoxam. However, dinotefuran was more toxic than either imidacloprid or thiamethoxam to both IM-R and GU-R strains as indicated by low LC50s. By contrast, a Q-biotype Spanish-resistant strain (SQ-R) of B. tabaci highly resistant to imidacloprid demonstrated high cross-resistance to the two related neonicotinoids. Field populations from Imperial Valley (California), Maricopa and Yuma (Arizona), showed variable susceptibility to imidacloprid (LC50s ranging from 3.39 to 115 μg ml–1) but did not exhibit cross-resistance to the three neonicotinoids suggesting that all three compounds would be effective in managing whiteflies. Yuma populations were the most susceptible to imidacloprid. Dinotefuran was the most toxic of the four neonicotinoids against field populations. Although differences in binding at the target site and metabolic pathways may influence the variability in cross-resistance patterns among whitefly populations, comparison of whitefly responses from various geographic regions to the four neonicotinoids indicates the importance of ecological and operational factors on development of cross-resistance to the neonicotinoids.

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Occurrence of Eretmocerus mundus Mercet (Hymenoptera: Aphelinidae) parasitizing Bemisia tabaci (Genn.) biotype B (Hemiptera: Aleyrodidae) in Brazil

Bragantia ◽

10.1590/brag.2014.025 ◽

2014 ◽

Vol 73 (2) ◽

pp. 160-162 ◽

Cited By ~ 2

Author(s):

André Luiz Lourenção ◽

Valmir Antonio Costa ◽

Lillian Silveira Pereira ◽

Juliana Cardoso Prado

Keyword(s):

Bemisia Tabaci ◽

Sao Paulo ◽

First Report ◽

Paulo State ◽

Experimental Station ◽

Eretmocerus Mundus ◽

Cotton Plants ◽

Cotton Genotypes ◽

São Paulo State ◽

Biotype B

The parasitism of Bemisia tabaci (Genn.) biotype B nymphs on cotton plants was observed during a research on resistance of cotton genotypes to this whitefly. The experiment was set in a greenhouse at the Experimental Station of the Instituto Agronômico (IAC), in Campinas, São Paulo State, Brazil. Samples of the parasitized nymphs were collected and maintained in laboratory to monitor the parasitism and obtain the adult parasitoids. A total of 129 adult parasitoids were obtained, including one Encarsia inaron (Walker), 13 En. lutea (Masi), and 115 Eretmocerus mundus Mercet (Hymenoptera: Aphelinidae). This is the first report of Er. mundus in Brazil.

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Efficacy of Selected Insecticides as Replacement for Neonicotinoids in Managing Sweetpotato Whitefly on Poinsettia

HortTechnology ◽

10.21273/horttech04853-21 ◽

2021 ◽

pp. 1-8

Author(s):

Gunbharpur Singh Gill ◽

Juang Horng Chong

Keyword(s):

Bemisia Tabaci ◽

Foliar Spray ◽

Euphorbia Pulcherrima ◽

Spray Application ◽

Sweetpotato Whitefly ◽

Neonicotinoid Insecticides ◽

Foliar Sprays ◽

Effective Suppression ◽

Application Methods

Management of sweetpotato whitefly (Bemisia tabaci), one of the most economically important pests of poinsettia (Euphorbia pulcherrima), relies heavily on neonicotinoid insecticides. Growers are seeking insecticide alternatives to neonicotinoids due to market demands. Although several systemic and translaminar insecticides have been suggested as alternatives to neonicotinoids, no published study has simultaneously compared their efficacies against sweetpotato whiteflies. This study compared the efficacies of 10 systemic and translaminar alternative insecticides with those of two systemic neonicotinoids, when all products were applied as foliar spray (twice at 14 d) or substrate drench (once) against sweetpotato whiteflies on poinsettia plants. Sweetpotato whitefly nymph and adult densities were examined 2 weeks before the first application (pretreatment), and weekly after the application for 8 weeks. Results showed that insecticides varied greatly in their efficacy, particularly against adults, and that spray application provided more effective suppression of nymphs than drench application. Spray and drench applications of imidacloprid and dinotefuran were consistently the most effective against sweetpotato whitefly nymphs and adults. Among the neonicotinoid alternatives, cyantraniliprole was the most effective insecticide in reducing sweetpotato whitefly nymph densities by both spray and drench application methods, with efficacy comparable to those of imidacloprid and dinotefuran. Although less effective than cyantraniliprole, foliar sprays of afidopyropen, chloratraniliprole, cyclaniliprole, flonicamid, flupyradifurone, pyrifluquinazon, spirotetramat, and sulfoxaflor + spinetoram were also effective against nymphs and could serve as partners in an insecticide rotation program.

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