1. Exploring virulence of new and less studied species of <italic>Metarhizium</italic> spp. from Brazil for two-spotted spider mite control.
- Author
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Castro, Thiago, Eilenberg, Jørgen, and Delalibera, Italo
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TWO-spotted spider mite ,MICROBIAL virulence ,METARHIZIUM ,STRAWBERRIES - Abstract
The two-spotted spider mite
Tetranychus urticae is an important pest of strawberry crops in Brazil and many other countries. Focus for biocontrol studies involving entomopathogenic fungi has been on three species from the genusMetarhizium :M. anisopliae sensu stricto (s.s.),M. brunneum andM. robertsii . Also, the speciesBeauveria bassiana has been studied for spider mite control and one isolate (ESALQPL63) is commercially available in Brazil. New and undescribedMetarhizium species have been found recently in Brazil and provide a pool of isolates with potential for biocontrol in Brazil and probably also elsewhere. The mortality of adult females ofT. urticae when exposed to four new Brazilian species ofMetarhizium was compared to the mortality when exposed toM. anisopliae s.s.,M. brunneum ,M. pingshaense ,M. robertsii andBeauveria bassiana ESALQPL63. Fungal suspensions were sprayed onto mites at 107 conidia/mL with 0.05% Tween 80 in laboratory bio-assays. We measured total mortality and percentage sporulating cadavers 10 days after exposure and calculated median lethal time (LT50 ). The lowest LT50 (4.0 ± 0.17) was observed for mites treated withMetarhizium sp. Indet. 1 (ESALQ1638), which also performed well with respect to mortality after 10 days and capacity to sporulate from cadavers. Among the other little studied species tested,M. pingshaense (ESALQ3069 and ESALQ3222) andMetarhizium Indet. 2 (ESALQ1476) performed well and were comparable toB. bassiana (ESALQPL63). The newMetarhizium isolates and species thus showed potential for biological control. [ABSTRACT FROM AUTHOR]- Published
- 2018
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