Toxic and repellent impacts of botanical oils against Callosobruchus maculatus (Bruchidae: Coleoptera) in stored cowpea [Vigna unguiculata (L.) Walp.]

Abstract

Cowpea (Vigna unguiculata) is an important legume which is consumed globally for protein intake, particularly in Asian states. It is a well-known source of dietary fiber, protein, minerals, and vitamins. The cowpea grains are stored after harvest and used till the next harvest. However, the grains are infested by storage pests, primarily Callosobruchus maculatus. Hence, effective management strategies are needed to protect the stored grains form the pests. This study assessed the efficacy of some edible oils in suppressing C. maculatus infestation in stored cowpea grains. Four different botanical oils (i.e., mustard, neem, poppy, and pumpkin) at four different concentrations (i.e., 0.5, 1.0, 1.5 and 2.0 ml per 100 g grain) were included in the study. A control treatment without any botanical oil was also included for comparison. The relevant concentrations of botanical oils were poured into plastic containers containing 100 g cowpea grains and ten C. maculatus adults were released. The jars were sealed and placed at room temperature. Data relating to mortality, oviposition, F1 adult emergence, and seed weight loss were recorded. The tested botanical oils and their concentrations significantly affected mortality after one day. Mortality after 2nd and 3rd days remained unaffected by botanical oils and their different concentrations. The highest mortality was recorded in neem oil-treated grains followed by poppy, pumpkin, and mustard oils. Increased oviposition rate was observed in the grains treated with mustard and pumpkin oils, while those treated with neem and poppy oil recorded decreased oviposition. The control treatment had increased oviposition rate compared to tested botanical oils. All botanical oils significantly inhibited egg laying percentage. The highest germination was recorded for the grains treated with mustard oil followed by pumpkin, poppy, and neem oils, respectively. The lowest germination was recorded for control treatment. Significant differences were noted for C. maculatus repellency among botanical oils. No emergence of adults (F1 progeny) was recorded in all tested botanical oils; thus, F1 progeny was inhibited by 100%. Weight loss, damage percentage, and holes in the grains were not recorded since F1 progeny did not emerge. It is concluded that tested botanical oils are promising and could be utilized to control C. maculatus in cowpea grains during storage.

Management of Mexican Bean Beetle, Zabrotes subfasciatus (Boheman) (Coleoptera: Chrysomelidae) with Botanical powders and oils in Common Bean (Phaseolus vulgaris L.)

“…The study on the toxic and repellent effect of mustard, neem, poppy, and pumpkin at four different concentrations 0.5, 1.0, 1.5, and 2.0 mL per 100 g grain, signi cantly affected the mortality of C. maculatus after one day. Among those tested botanical oils, grain treated with neem oil resulted in highest mortality (Nisar et al, 2022).…”

“…This hole eventually led to seed damage and contributed to percentage weight loss. Similarly, Nisar et al (2022) reported that weight loss, damage percentage, and holes in the grains were not recorded because F 1 progeny did not emerge.…”

“…In addition, the result of seed damage showed neem seed extract gave the lowest seed damage at 0.5 and 1.0 mL/10 g. Neem seed oil at 5, 7.5, and 10 mL/kg resulted in more effective in reducing weight loss by pulse beetle, C. chinensis, in stored black gram grains and posed a signi cant reduction of adult emergence recorded(Pathania et al, 2020).The ethanolic extracts of Solanum lycocarpum were found to reduce the damage on bean grains caused by Z. subfasciatus(Gonçalves et al, 2021). Cowpea seeds treated with neem, mustard, poppy, and pumpkin oil at different concentrations did not exhibit any weight loss and no holes on the seed(Nisar et al, 2022). A comparison made between different doses (2.5 and 5%) of commercial neem oil (TopBio) and synthetic insecticide Antouka Super showed neem oil exhibited a strong repulsion against Dinoderus porcellus at all tested concentrations.…”

Insecticidal Efficacy of Azadirachta indica (A. Juss) and Ricinus cummunis (L.) Seed Oil Against Callosobruchus maculatus (F.) on Stored Mung Beans (Vigna radiata L. Wilczek)

“…Our outcomes that neem and castor oils worked as a surface protectants are close to Rahman and Talukder (2006) they used different plants oil of neem, safflower and sesame to observe their surface protectants efficacy on black grams against C. maculatus and revealed that among different oils neem oil was the best surface protectant. Nisar et al (2022) also assessed the effectiveness of some botanical essential oils against C. maculatus i.e., Neem, mustard, pumpkin and popy. They prepared o.5, 1.0, 1.5 and 2.0 mL concentrations of the oils.…”

Retraction: Toxic and repellent impacts of botanical oils against Callosobruchus maculatus (Bruchidae: Coleoptera) in stored cowpea [Vigna unguiculata (L.) Walp.]

“…The PLOS ONE Editors retract this article [ 1 ] because it was identified as one of a series of submissions for which we have concerns about authorship, competing interests, and peer review. We regret that the issues were not addressed prior to the article’s publication.…”