Determining Field Insecticide Efficacy on Whiteflies with Maximum Dose Bioassays

The sweetpotato whitefly, Bemisia tabaci MEAM1, is a pest known to significantly impact tomato development and yields through direct damage and virus transmission. To manage this pest, the current study compared the effectiveness of various insecticide rotations. Field trials included rotations involving synthetic insecticides, biochemicals, and microbial agents, applied according to their highest labeled concentrations. The results indicated that while standard synthetic insecticides consistently reduced whitefly egg and nymph counts significantly, microbial biopesticide rotations also achieved reductions, although less consistently. This study demonstrated that while traditional chemical treatments remain highly effective, microbial biopesticides containing Beauveria bassiana and Cordyceps javanica present a viable alternative to manage MEAM1 in tomato fields. The data generated in this study provided baseline information for further investigations to determine the potential for optimizing integrated pest management (IPM) and insecticide resistance management (IRM) strategies by incorporating microbial biopesticides in rotations with a variety of modes of action to sustainably manage B. tabaci MEAM1 populations in agricultural settings.

Section: Discussionmentioning

confidence: 99%

Evaluation of Biopesticides for Management of Bemisia tabaci Middle East-Asia Minor 1 (Hemiptera: Aleyrodidae) in Florida

Dimase,

Lahiri,

Beuzelin

et al. 2024

“…The maximum dose bioassay is a valuable tool for assessing the efficacy of insecticides against pests, offering the advantages of being rapid, easy to set up, and cost effective [ 30 , 31 , 32 ]. We employed the maximum dosage bioassay to evaluate the efficacy of spinetoram against 212 field populations of M. usitatus collected from 20 villages in the Yazhou District of Hainan.…”

Section: Discussionmentioning

confidence: 99%

“…De Marchi et al (2021) performed the maximum dose bioassay to assess a variety of insecticides against multiple field populations of whitefly in Florida, thereby enhancing pest management recommendations as part of an integrated management approach. In order to reduce crop damage and increase yields [ 32 ], Cremonez et al (2023) conducted maximum dose bioassays of various insecticides against sweet potato whitefly in pumpkins and cucumbers [ 31 ]. In the present study, we employed the maximum dosage bioassay to determine whether spinetoram remains effective against cowpea thrips in Yazhou District, Sanya.…”

Section: Discussionmentioning

confidence: 99%

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A Maximum Dose Bioassay to Assess Efficacy of Spinetoram against Cowpea Thrip Megalurothrips usitatus in China

Yu,

Wu,

et al. 2024

The bean flower thrip Megalurothrips usitatus (Bagnall) is a severe pest on cowpeas and causes a 20–30% reduction in cowpeas in Hainan, China, with even complete crop failure in severe cases. Spinetoram is currently the most important pesticide against M. usitatus in cowpea production. In the main producing areas of cowpeas in Hainan, however, the efficacy of spinetoram against M. usitatus is not well known. In the present study, we employed the maximum dose bioassay to evaluate the efficacy of the mortality rates of adult thrips at F0 in spinetoram, freshly collected from 212 field populations of M. usitatus collected from 20 villages in the Yazhou District of Hainan. Our results showed that the mortality rates of these thrip populations exposed to spinetoram were from 3.31% to 100%. Among them, the mortality rates of 66.98% (142/212) of the populations exceeded 80%, while that of 33.96% (72/212) of the populations surpassed 90%. Only a small proportion of 0.47% (1/212) the populations exhibited a mortality rate below 10%, and 4.72% (10/212) displayed rates below 50%. Furthermore, significant differences were also observed in the mortality rates of thrips among different villages. Taken together, the maximum dosage bioassay method is a rapid and easily implemented approach providing valuable insights into the field efficacy of insecticides and offers guidance in determining the optimal dosage required in the field. Spinetoram is still effective against M. usitatus in the main producing areas of cowpeas in Hainan, but caution should be exercised in its combined use with other methods to reduce potential resistance.

“…It is reported to be effective on nicotinoid-resistant B. tabaci in cotton, opening new options for resistance management. Flupyradifurone has been evaluated using various assays under laboratory and field conditions and is reported to be among the most effective insecticides against adult B. tabaci whiteflies [13][14][15]. Flupyradifurone has also been shown to control whiteflytransmitted viruses through the suppression of transmission [16,17].…”

Section: Introductionmentioning

confidence: 99%

Cutting Dipping Application of Flupyradifurone against Cassava Whiteflies Bemisia tabaci and Impact on Its Parasitism in Cassava

Caspary,

Wosula,

Issa

et al. 2023

The cassava whitefly Bemisia tabaci causes damage in cassava through the feeding and vectoring of plant viruses that cause cassava mosaic and cassava brown streak diseases. This study sought to explore the efficacy of cutting dipping in flupyradifurone for whitefly control and the impact of the mode of application on whitefly parasitism under farmer field conditions. The insecticide treatment significantly reduced adult whiteflies by 41%, nymphs by 64%, and cassava mosaic disease (CMD) incidence by 16% and increased root yield by 49%. The whitefly parasitism rate by Encarsia spp. parasitoids was 27.3 and 21.1%, while Eretmocerus spp. had 26.7 and 18.0% in control and flupyradifurone, respectively, and these differences were not significant. Electropenetrography recordings of whitefly feeding behaviour on flupyradifurone-treated plants showed significantly reduced probing activity and a delay in reaching the phloem as compared to the control. The findings from this study demonstrated that cassava cutting dipping in flupyradifurone significantly reduces whitefly numbers and cassava mosaic disease incidence, thus contributing to a significant root yield increase in cassava. Flupyradifurone applied through cutting dips does not significantly impact parasitism rates in cassava fields. Routine monitoring of parasitoids and predators in insecticide-treated versus control fields should be emphasized to determine the impact of pesticides on these beneficial non-target organisms.