Exploring virulence of new and less studied species of Metarhizium spp. from Brazil for two-spotted spider mite control

Author(s)

Castro, Thiago ^{[1, 2]} ; Eilenberg, Jorgen ^[1] ; Delalibera, Jr., Italo ^[2]

Affiliation

^[1] Univ Copenhagen, Dept Plant & Environm Sci, Thorvaldsensvej 40, DK-1871 Frederiksberg C - Denmark

^[2] Univ Sao Paulo, Dept Entomol & Acarol, ESALQ, Ave Padua Dias 11, POB 9, BR-13418900 Piracicaba, SP - Brazil

• Document type: Journal article
• Source: Experimental and Applied Acarology; v. 74, n. 2, p. 139-146, FEB 2018.
• Web of Science Citations: 2

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 genus Metarhizium: M. anisopliae sensu stricto (s.s.), M. brunneum and M. robertsii. Also, the species Beauveria bassiana has been studied for spider mite control and one isolate (ESALQPL63) is commercially available in Brazil. New and undescribed Metarhizium 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 of T. urticae when exposed to four new Brazilian species of Metarhizium was compared to the mortality when exposed to M. anisopliae s.s., M. brunneum, M. pingshaense, M. robertsii and Beauveria bassiana ESALQPL63. Fungal suspensions were sprayed onto mites at 10(7) 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 with Metarhizium 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) and Metarhizium Indet. 2 (ESALQ1476) performed well and were comparable to B. bassiana (ESALQPL63). The new Metarhizium isolates and species thus showed potential for biological control. (AU)

• FAPESP's process: 13/24430-4 - Strategies for implementation of entomopathogenic fungi in integrated pest management of strawberry
• Grantee: Thiago Rodrigues de Castro
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• FAPESP's process: 11/51556-3 - IMBICONT: Improved biological control for IPM in fruits and berries
• Grantee: Italo Delalibera Júnior
• Support Opportunities: Regular Research Grants
• FAPESP's process: 13/10517-0 - Strategies for entomopathogenic fungi usage in integrated pest management of strawberry
• Grantee: Thiago Rodrigues de Castro
• Support Opportunities: Scholarships in Brazil - Doctorate