The enhanced infectivity of Metarhizium flavoviride in oil formulations to desert locusts at low humidities

Abstract

SummaryFormulation in non‐evaporative diluents such as oils is required to exploit the advantages of controlled droplet application methods for biopesticides based on conidial suspensions of entomopathogenic fungi. In laboratory assays on desert locusts (Schistocerca gregaria), formulations of Metarhizium flauoviride conidia in cotton seed oil showed superior performance to water‐based suspensions and this was especially pronounced at low humidities (35% r.h.). The LD50s for oil and water suspensions at 5 days were 8900 and > 106 conidia/insect respectively. The dose‐mortality regression line for oil was more than four times steeper and median lethal times were typically 76% of those for aqueous suspensions. Formulation in oil improves the efficacy of this fungus and may extend the application of species with lipophilic conidia into less humid agricultural environments.

SELEÇÃO DE ISOLADOS DE FUNGOS ENTOMOPATOGÊNICOS PARA O CONTROLE DE Hedypathes betulinus E AVALIAÇÃO DA PERSISTÊNCIA

“…As formulações de fungos entomopatogênicos à base de óleo são superiores àquelas à base de água, especialmente em locais onde a umidade é baixa (BATEMAN et al, 1993). Formulações em óleo prolongam a sobrevivência do conídio e diminuem a sensibilidade a radiações UV quando comparada com suspensões aquosas (INGLIS et al, 1995).…”

Microbial control of the exotic spiralling whitefly, Aleurodicus dispersus (Hemiptera: Aleyrodidae) on eggplant using entomopathogenic fungi

“…This could be due to the fact that M. anisopliae was the least effective and this contained lesser density conidia. Thus, the infection was slow as the speed of kill is related to the number of conidia received by the individual pest (Bateman et al, 1993). Studies by Boopathi et al (2013) also observed that M. anisopliae caused the lowest pathogenic to A. dispersus under laboratory conditions.…”

Effect of Metarhizium anisopliae (Ascomycete), Cypermethrin, and D-Limonene, Alone and Combined, on Larval Mortality of Rhipicephalus sanguineus (Acari: Ixodidae)

“…This effect was previously reported by Bahiense et al (2006) using M. anisopliae and deltamethrin applied against Boophilus microplus where 36.5% mortality was seen with concentrations ranging between 0.39 and 6.25 ppm of deltamethrin applied alone; mortalities of 16.5%, 55%, and 96.9% with the concentrations of 2.2 Â 10 5 , 2.2 Â 10 6 , 2.2 Â 10 7 up to 2.2 Â 10 8 conidia/ml of the fungus applied alone, respectively; and with mixed treatments causing 68%, 54%, 100%, and 100% using the highest concentration of deltamethrin with the fungal concentrations, respectively. It was expected that concentrations of D-limonene mixed with the fungal concentrations would improve the suspension of the conidia, producing an oily emulsion and increasing the spore density that facilitated the adhesion of the conidia to the larval cuticle and thereby causing higher mortality (Bateman et al 1993). Oily plant extracts have an acaricide effect against ticks (Abdel-Shafy and Soliman 2004); the oily plant extracts of plants belonging to the families Meliaceae, Lamiaceae, Labiatidae, and others, have acaricidal effects against ticks due to their chemical composition.…”