Laboratory bioassay of Beauveria bassiana against Tetranychus urticae (Acari: Tetranychidae) on leaf discs and potted bean plants

Abstract

Use of the mycopathogen Beauveria bassiana (strain GHA), marketed as BotaniGard(®) ES, was evaluated as a plant protection strategy against the spider mite Tetranychus urticae Koch, which is considered one of the most economically important and cosmopolitan pests of many crops. Tetranychus urticae were treated with four concentrations of conidia (1 × 10(5), 1 × 10(6), 1 × 10(7), or 1 × 10(8) conidia/ml), and virulence was assessed on mites held at four relative humidity levels (35, 55, 75, and 95 ± 2 % RH) at 25 ± 1 °C. At 1 × 10(8) spores/ml, the LT50 value was 9.7 h at 95 % RH, which was significantly lower than values for other RH levels. At 1 × 10(7) spores/ml, the LT50 value was 43.8 h at 95 % RH, which was significantly different from values at 55 and 35 % RH. The efficacy of B. bassiana product was also verified on mites infesting potted bean plants with a concentration of 1 × 10(8) spores/ml. In double spray treatment where applications were made 2 × on days 5 and 10 after mite infestation, the nymphal and adult population of T. urticae were reduced to zero on days 20 and 15, respectively. With a single spray on day 5, the nymphal population was also greatly reduced, but increased rapidly after day 20. Single and double sprays with B. bassiana reduced leaf damage as measured by image analysis by 33 and 94 % compared to no treatment, respectively. These results suggest that 1 × 10(8) spores/ml was the most effective dose and that two applications, at a 5-day interval, provided control of T. urticae in our laboratory assay.

Pathogenicity of Metarhizium anisopliae and Beauveria bassiana fungi to Tetranychus ludeni (Acari: Tetranychidae)

“…The leaf circles were surrounded with cotton, moistened with distilled water, and placed over nylon foam and in a tray. The foam was kept moist with the addition of distilled water (SOARES et al, 2012;ULLAH;LIM, 2015).…”

“…Suspensions containing fungal conidia were obtained from the commercial products Metarril ® WP E9 and Boveril ® WP PL 63 (Koppert Biological Systems). Conidia was suspended in an aqueous solution containing 0.01% Tween ® 80 (ALMEIDA et al, 2006;ULLAH;LIM, 2015) at concentrations of 10 6 and 10 7 con.mL -1 for each isolate. Leaf circles were sprayed 100 µL of the suspensions of the isolates of M. anisopliae and B. bassiana, homogeneously.…”

Survey of indigenous entomopathogenic fungi and evaluation of their pathogenicity against the carmine spider mite, Tetranychus cinnabarinus (Boisd.), and the whitefly, Bemisia tabaci (Genn.) biotype B

“…Also, Soetopo indicated that there are many different strains of B. bassiana that exhibit considerable variation in their virulence and host ranges. More recently, Ullah and Lim tested the pathogenicity of the mycopathogen B. bassiana (strain GHA), marketed as BotaniGard ® ES (Arysta LifeScience, Tokyo, Japan), against T. urticae under laboratory conditions, and the results showed that mortality greatly increased with the conidial concentration of the product and increasing time. Time‐dependent increases in mortality were also observed in the present study.…”

Isolation, Molecular Identification and Host Range Evalution of Metarhizium anisopliae Egyptian Isolate

“…Our results proved the pathogenicity of M. anisopliae against the four tested insect pest and these agree with Tamai et al (2002) who investigated the effects of 45 isolates of B. bassiana, M. anisopliae, and Paecilomyces farinosus on T. urticae and found that M. anisopliae was more pathogenic than other fungi used in the study. Bugeme et al (2014) and Ullah and Lim (2015) studied the effect of different concentrations of M. anisopliae and B. bassiana on T. urticae and noticed highest mortality rate, 98% was achieved by M. anisopliae isolate so stated that M. anisopliae is the highly effective agent that can be used in the control of both T. urticae nymphs and adults.…”