Efficacy of Beauveria bassiana (Balsamo) Vuillemin isolates for control of stored‐grain pests

Abstract

Seventy two isolates of Beauveria bassiana or Metarhizium anisopliae were screened for control of Sitophilus oryzae, S. zeamais (Col., Curculionidae), and Rhyzopertha dominica (Col., Bostrychidae). Beauveria bassiana isolates produced highest mortalities against all three hosts. Ten isolates (all B. bassiana) were selected for further experimentation in the second phase of selection process. Bioassays were conducted by inoculating 50 adult insects of each species, maintained at 26 OS'C, 70 f 10% RH, 12 h photophase, for 10 days. The cumulative mortalities after 10 days exposure and lethal time for 50% of the population (LT50) were calculated and compared. S. oryzae and S. zeamais were less susceptible to B. bassiana isolates than R. dominica, which was completely killed by several isolates. Isolate 476 was the most virulent to S. oryzae, and isolate 604 was the most virulent to S. zeamais. Isolate 604 was best overall, but isolates 476 and 643 should also be considered as control agents for stored-grain pests. A combination of isolates may be advantageous if mixed pest infestations occur.

Toxicity of some insecticides to Tetranychus urticae, Neoseiulus californicus and Tydeus californicus

“…Alves et al (2002) observed mortality ranging from 43 to 78% of some isolates for B. bassiana on this spider mite. However, different isolates of the fungus exhibited a certain variability in pathogenicity and virulence toward different arthropods (Almeida et al, 1997;Moino et al, 1998). In our test, B. bassiana had a slight, positive effect on T. urticae fecundity, but reduced female and egg survival.…”

Seleção de isolados de Beauveria bassiana para o controle biológico da broca-do-café, Hypothenemus hampei (Ferrari) (Coleoptera: Scolytidae)

“…Na fase de screening é possível descartar materiais pouco virulentos e com baixa capacidade de penetração e germinação (Moino Jr. 1998). Assim, nesta primeira etapa optou-se pela seleção baseada na mortalidade confirmada (> 60%), eliminando-se os isolados com baixa esporulação.…”

Production of extracellular protease by a Brazilian strain of Beauveria bassiana reactivated on coffee berry borer, Hypothenemus hampei

“…The entomopathogenic fungus can diversify the production of virulence factors in response to the different insects (Moino et al, 1998). Inducer substrates have been tested in order to increase the protein content and to release the extracellular proteases to make easier the studies on kinetic activity and structure and to correlate with virulence levels of the fungal strain in bioassays on insects.…”