Compatibility between the entomopathogenic fungus Beauveria bassiana and insecticides used in coffee plantations

Abstract

Microbial control in integrated pest management (IPM) programs of coffee plantations is an important factor for the reduction of pest population densities. The use of selective pesticides can be associated with entomopathogens, increasing the efficiency of the control and reducing the use of required insecticides. The in vitro fungitoxic effect of insecticide formulations of Thiamethoxam, Cyfluthrin, Deltamethrin, Alpha-Cypermethrin, Triazophos, Chlorpyrifos, Fenpropathrin and Endosulfan and Beauveria bassiana (CG 425 strain) was evaluated at three concentrations (FR = average field recommendation; 0.5 ´ FR and 2 ´ FR). Effects of these products on conidia germination, vegetative growth and sporulation were compared. Only five insecticides, at the FR concentration, promoted conidia viability higher than 60%. Viability should be considered the most important factor to be evaluated since it is the first step of the infection process. The insecticide formulations of Alpha-Cypermethrin, Thiamethoxam and Cyfluthrin caused the lower inhibition level on conidia germination at the two lower concentrations, with no difference in relation to the control. With respect to vegetative growth analysis, Thiamethoxam at the two lower concentrations was not found to cause radial growth inhibition. Thiamethoxam caused the smallest inhibition level with regard to conidia production. The use of Alpha-Cypermethrin and Thiamethoxam formulations in coffee IPM programs for a B. bassiana inoculum conservation strategy are recommended, since these products were compatible with the entomopathogenic fungus Beauveria bassiana (CG 425), an important natural control agent of the coffee berry borer, Hypothenemus hampei.

Action of pesticides to Metarhizium anisopliae in soil

“…Nevertheless, according to the last authors, deltametrin presented marked toxicity to M. anisopliae and other entomopathogenic fungi. Similar results have been reported by Oliveira et al (2003), who observed a strong toxic effect of this product on the germination, vegetative growth and spore production of B. bassiana. When we analyzed the toxicity of deltametrin to M. anisopliae in soil, no significant difference in fungal respiratory activity was observed between this treatment and the control.…”

Compatibility of the fungus Beauveria Bassiana (Bals.) Vuill. (Deuteromycetes) with extracts of neem seeds and leaves and the emulsible oil

“…Therefore, preservation of entomopathogens that occur naturally, or are introduced for insect control, should be observed (Oliveira et al 2003). In addition, we must understand the compatibility of entomopathogenic fungi with other crop production techniques such as the use of insecticides, which may inhibit to a smaller or larger extent the development and reproduction of pathogen (Malo 1993).…”

“…Endosulfan, an organochlorine, is still the most common treatment against H. hampei, in spite of its fungitoxic effects on Beauveria bassiana (Mourão et al 2003, Oliveira et al 2003, one of the most important, naturally occurring pathogens of coffee berry borer. Continuous utilization of endosulfan may promote the selection of populations that are resistant to the insecticide and to other products of the same chemical group (Brun et al 1989(Brun et al , 1994, as well as cause environmental problems and farmers intoxication.…”

Efeito da temperatura e cama do aviário na virulência de Beauveria bassiana (Bals.) Vuill. e Metarhizium anisopliae (Metsch.) para o controle do cascudinho (Alphitobius diaperinus) (Panzer) (Coleoptera: Tenebrionidae)

“…A comparação de tais resultados com os de outros trabalhos na literatura demonstra a grande variação existente entre os isolados, haja vista que Pachamuthu et al (1999), Oliveira et al (2003) e Andaló et al (2004), obtiveram entre 4,9 × 10 7 a 1,6 × 10 9 conídios/colônia, provavelmente em decorrência da variabilidade genética entre os isolados.…”