Compatibility of entomopathogenic fungi with insecticides and their efficacy for IPM of <i>Bemisia tabaci</i> in cotton

Abstract

Bemisia tabaci, a vector of cotton leaf curl virus disease, is among the most devastating pests causing huge economic losses due to reduced cotton yield and quality. The excessive use of chemical pesticides causes insecticide resistance. Entomopathogenic fungi (EPFs) have a role as mycoinsecticides. The combined use of these insecticides is a promising pest-control option to minimize adverse chemical effects. Thus, we have evaluated 10 EPFs under polyhouse conditions for their virulence against whitefly nymphs and their compatibility with chemical and botanical insecticides. The highest overall biological efficacy index was recorded with Ij-102, followed by Bb-4511, and Ij-089. An in vitro compatibility study was conducted to evaluate the effect of botanical and chemical pesticides on mycelial growth and spore production using the poisoned food technique. The effect of pesticides on the reduction of mycelial growth and conidial production ranged from −169 to 94.1% and −25.6 to 87.6%, respectively. However, Ij-089, Ij-102, Ma-1299, and Bb-4511 were found to be the most compatible with the chemical and botanicals evaluated. Comparatively, spiromesifen, diafenthiuron, buprofezin, pyriproxyfen, and flonicamid were more compatible with EPFs at half doses, as compared to the other chemical pesticides, namely imidacloprid, fipronil, profenophos, and triazophos. These results might provide the basis for future work and indicate that applications of EPFs showing the best virulence and compatibility have the maximum likelihood for the management of B. tabaci in the field in an integrated pest management system.

Molecular phylogeny and pathogenicity of indigenous Beauveria bassiana against the tomato leafminer, Tuta absoluta Meyrick 1917 (Lepidoptera: Gelechiidae), in Ethiopia

“…In addition, biological characteristics such as spore viability, sporulation rate, and pathogenicity against their host insect are the vital attributes to screen effective strains of entomopathogens [ 31 ]. Therefore, we have screened our isolates based on the biological efficiency index determination (31), and 12 (44.4%) of the isolates were scored above 80% of BEI.…”

“…Based on these screening procedures, the cumulative biological efficacy index (BEI) was computed by using formula stated by Sain et al . [ 31 ] with some modification; BEI (%) = 37 (SG) + 13 (RSR) + 50 ( LM), where SG means spore germination, RSR means relative sporulation rate, and LM means larval mortality of G. mellonella in 10 days post inoculation of spores.…”

Sublethal concentrations of spinosad synergize the pathogenicity of fungi to larvae of Ephestia kuehniella (Lepidoptera: Pyralidae)

“…Interestingly, larvae of E. kuehniella show a preference for remaining on surfaces treated with spinosad, a response which might help improve its uptake and effi cacy (Athanassiou et al, 2018), and spinosad would appear to be compatible with the parasitoid Habrobracon hebetor, which can also be used for control of E. kuehniella (Mahdavi et al, 2015). Spinosad has a successful history of application against stored product pests (Subramanyam et al, 2014;Nayak & Daglish, 2017) and is often applied in combination with low doses of diatomaceous earth to improve its effi cacy (Machekano et al, 2017(Machekano et al, , 2019Gad et al, 2021) The combined use of this naturally-derived insecticide and an EPF could potentially increase the effi ciency of pest control while minimizing adverse chemical impacts (Paula et al, 2011;Sain et al, 2019). However, the possibility exists that certain insecticides could inhibit the germination or fungal growth of EPF, rendering them incompatible for joint application (da Silva et al, 2013).…”

Effect of the native strain of the predator Nesidiocoris tenuis Reuter and the entomopathogenic fungi Beauveria bassiana and Lecanicillium muscarium against Bemisia tabaci (Genn.) under greenhouse conditions in Tunisia

“…Control of this pest has been based primarily on the use of conventional broad-spectrum chemical pesticides. As a result, B. tabaci developed resistance against different groups of insecticides following their intensive use (Sain et al, 2019). In addition to marketing problems, the use of chemicals in a heated greenhouse could pose poisoning problems for farmers (Bel Kadhi, 2004).…”