PATOGENICIDADE DE BEAUVERIA BASSIANA (BALS.) VUILL. AO ÁCARO Tetranychus urticae KOCH

Abstract

O estudo da patogenicidade de Beauveria bassiana (Bals.) Vuill. ao ácaro Tetranychus urticae Koch foi desenvolvido a 25 ± 2°C, 70 ± 5% UR e 12 horas de fotofase, utilizando-se fêmeas recém-emergidas. Os ácaros foram mantidos durante seis dias em discos de folha de Canavalia ensiformis (L.) DC. inoculadas com B. bassiana, isolado 447, nas concentrações: 5x106, 1x107, 5x107, 1x108, 5x108 e 1x109 conídios/ml. Este isolado mostrou-se patogênico a T. urticae, apresentando aumento nos valores das mortalidades acumuladas (total, corrigida e confirmada) à medida que a suspensão de conídios se tornou mais concentrada. Nas seis concentrações testadas, os valores de mortalidade corrigida ao sexto dia, foram inferiores a 50%, sendo observada apenas na concentração de 1x109 conídios/ml, mortalidade total superior a 50%.

Compatibility of conventional agrochemicals used in rice crops with the entomopathogenic fungus Metarhizium anisopliae

“…In other cases, the fungus grows well during its vegetative development, but later conidiation does not take place for reasons which are not understood. There is no positive relationship between vegetative growth and conidial yield and the factors that govern this outcome warrant further detailed investigations (Tamai et al, 2002). In the current Biological Index proposed by Rossi-Zalaf et al (2008), there is a low weight attributed to the germination parameter (i.e., 10 %) in comparison to the other variables (vegetative growth and conidiation).…”

Selection of Beauveria bassiana (Bals.) Vuill. and Metarhizium anisopliae (Metsch.) Sorok. for the control of the mite Mononychellus tanajoa (Bondar)

“…The 645 B. bassiana isolate showed a lower LC 50 than the CG321 M. anisopliae isolate, thus demonstrating that the first was more pathogenic than the second. Tamai et al (1999), using the 447 B. bassiana isolate on females of the mite T. urticae, concluded that only at the concentration of 1 × 10 9 conidia mL -1 there was a total mortality higher than 50%. , a total mortality of only 41.0 % and a confirmed mortality of only 31.0 % were obtained.…”

Use of Entomopathogenic Fungi in Latin America

“…Studies are under way on the use of pathogens in the suppression of insect and mite populations in protected crops. Great potential has been demonstrated for the fungi B. bassiana and M anisopliae for control of Tetranychus urticae (Acari: Tetranychidae) (Table 3), Frankliniella occidentalis (Thysanoptera: Thripidae), and Bemisia tabaci (Hemiptera: Aleyrodidae) (Alves et aI., 1998b;Tamai et a!., 1999;Ramos et a!., 2000). The research program involves the selection of isolates of different fungal species for high viru1ence and conidial production, compatibility with chemical pesticides, survival under storage conditions and development cycles for the fungi on the pests.…”