Efficacy of bioactive compounds and their association with different cowpea cultivars against their major stored pest

Abstract

Background: Stored grain insects are controlled with fumigant insecticides which can select resistant insect populations and cause environmental and applicator contamination. Thus, resistant cultivars and chemical constituents of essential oils are an alternative to the almost exclusive use of these insecticides. The effects of the combination of cowpea cultivars Vigna unguiculata (L.) Walp. with chemical constituents of essential oils against Callosobruchus maculatus were determined. Four cowpea cultivars: BRS Tracuateua, BR 17 Gurgueia, Epace 10 and Sempre Verde (insect rearing) untreated were used in the experiments and combined with chemical constituents of essential oil: eugenol, geraniol and trans-anethole. The biological parameters observed were: total egg number and eggs per grain, egg viability (%), insects emerged and insects per grain, immature stage viability (%), instantaneous rate of growth (ri), insect dry weight (mg), grain weight loss (%) and egg-adult period. Results: When comparing all biological parameters, the cultivars BRS Tracuateua and BR 17 Gurgueia were harmful to C. maculatus. In the toxicity tests, the results showed that LC 30 and LC 50 of the chemical constituents ranged from 54.77 to 103.48 ppm and 60.99 to 125.18 ppm, respectively. In most of the biological parameters, LC 50 had adverse effects significantly higher than LC 30 and BR 17 Gurgueia treated were harmful to C. maculatus. Conclusions: Overall, the findings showed that BR 17 Gurgueia combined with eugenol and geraniol more significantly affected the biological parameters of C. maculatus than when associated with trans-anethole, reducing egg number, insects emerged and egg viability.

Identification of Volatile Compounds and Insecticidal Activity of Essential Oils from Origanum compactum Benth. and Rosmarinus officinalis L. against Callosobruchus maculatus (Fab.)

“…Moussa Kéïta et al [25] with a drop in the emergence of C. maculatus adults to 0 and 4% follow exposure to EOs of Ocimum basilicum and Ocimum gratissimum. It was also reported that the emergence of C. maculatus F 1 adults was significantly inhibited by EO of Alpinia calcarata at concentrations of 0.80 g/L using fumigant toxicity [28]. Similarly, the emergence of C. maculatus has been previously reported to be also controlled by Allium sativum [21].…”

“…Eugenol and (−)-menthone powerfully inhibited adult emergence C. maculatus adults [38]. e MOA by which terpenes can exert this insecticidal effect have been reported in an earlier work [28]. EO constituents can operate synergistically or individually depending on which insect pest is being targeted.…”

Combining host plant resistance and botanical insecticide for the management of Zabrotes subfasciatus (Boheman) (Coleoptera, Chrysomelidae, Bruchinae) in common bean

“…Bean resistance (Moraes et al 2011, Guzzo et al 2015, 2018, Eduardo et al 2016) and botanical insecticides , 2007, Barbosa et al 2002 have been largely studied for individual use against Z. subfasciatus in Brazil, with the identification of several genotypes resistant to the pest. The combination of plant resistance with botanical insecticides has been studied to control seed beetles (Coleoptera, Chrysomelidae, Bruchinae) in bean species worldwide (Lale and Mustapha 2000, Law-Ogbomo 2007, Tabadkani et al 2017, Barbosa et al 2020, with promising results from the economic and environmental perspectives, but little has been researched in relation to Z. subfasciatus (Luz et al 2017).…”

Potential ofFicus caricaextracts againstEuschistus heros: Toxicity of major active compounds and selectivity against beneficial insects

“…The natural environment likely holds a diversity of novel bioactive compounds, including those with the potential to be integrated with or replace synthetic compounds in the management of agricultural pests 3,16–19 . Plant‐based pesticides are currently among the most ecofriendly ways to control undesirable insects 20–25 . The plant species belonging to the Moracea family, especially those belonging to the genus Ficus , have been considered as promising sources for plant‐based bioactive compounds due to the presence of phenolic compounds, flavonoids, phytosterols, triterpenoids, volatile compounds, and coumarins 26–28 .…”