scholarly journals The Metapleural Secretion of Acromyrmex laticeps (Forel) does not have Fungicide Effect on the Entomopathogenic Fungus Beauveria bassiana (Bals.) Vuill

2014 ◽  
Vol 7 (3) ◽  
pp. 207-210
Author(s):  
Luciane Kern Junqueira ◽  
Elena Diehl

The metapleural gland (MPG) is an exocrine structure, exclusive to formicids, being more developed in females and workers. This structure is stunted or nonexistent in males. Several possible functions for the secretion produced by this gland have been suggested, but a protection against entomopathogens is the most accepted hypothesis. To test this, we applied a suspension of spores (1.30 x 106) of Beauveria bassiana (Bals.) Vuill. on the MPG and the antero-superior portion of the metathorax (ASM) of winged females of Acromyrmex laticeps (Forel). We only applied the suspension in the ASM of males, since they do not have the atrium characteristic in the MPG. Our results indicated that the metapleural secretion of females has no fungicidal effect on B. bassiana, and therefore both males and winged females are sensitive to this entomopathogenic fungus. Ausência de Efeito Fungicida da Secreção Metapleural de Acromyrmex laticeps (Forel) Contra Beauveria bassiana (Bals.) Vuill. Resumo. A glândula metapleural (GMP) é uma estrutura exógena, encontrada apenas nos formicídeos, sendo mais desenvolvida nas fêmeas e operárias, enquanto nos machos ou está atrofiada ou não existe. Tem sido sugerido várias possíveis funções para a secreção produzida por esta glândula, sendo a hipótese de efeito protetor contra entomopatógenos a mais estudada. Para testar esta hipótese, foi aplicada uma suspensão de conídios (1,30 x 106) de Beauveria bassiana (Bals.) Vuill. nas GMP e na porção ântero-superior do metatórax (ASM) de fêmeas aladas de Acromyrmex laticeps (Forel), enquanto nos machos a suspensão foi aplicada apenas na porção ASM, pois estes não apresentam o átrio característico da GMP. Os resultados obtidos indicaram que a secreção metapleural das fêmeas desta espécie não possui efeito fungicida sobre B. bassiana, e que tanto os machos como as fêmeas alados são sensíveis a este fungo entomopatogênico.

2019 ◽  
Vol 29 (1) ◽  
Author(s):  
Monir M. M. El Husseini

AbstractLarval and adult populations of the Egyptian alfalfa weevil (EAW) Hypera brunneipennis (Boheman) (Coleoptera: Curculionidae) was monitored after application of the entomopathogenic fungus Beauveria bassiana in the alfalfa field (Medicago sativa L.) in two successive seasons 2014/2015 and 2015/2016. The second and last generation of the weevil on April 10, 2016, was controlled by only one application with the conidiospores of the entomopathogenic fungus B. bassiana (3 × 108 spores/ml). Accordingly, the larval population decreased from 16.07 ± 1.09 in season 2015/2016 to 7.37 ± 0.05 individuals/50 sweep net double strokes in season 2016/2017. Also, the adult weevil’s population decreased from 5.66 ± 0.8 to 2.55 ± 0.6 individuals/50 sweep net double strokes in the two seasons, respectively. 39.66% mortality rate was recorded in the Hypera brunneipennis adults aestivated under loose bark of the surrounding eucalyptus trees, which received the application of B. bassiana in the field. Another application with the fungus, targeting the second generation of the pest adults in alfalfa each season, will undoubtedly lead to a further decrease in the pest population.


2003 ◽  
Vol 60 (4) ◽  
pp. 663-667 ◽  
Author(s):  
Carolina Natali de Oliveira ◽  
Pedro Manuel Oliveira Janeiro Neves ◽  
Lídio Sueki Kawazoe

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.


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