Beauveria brongniartii on white grubs attacking sugarcane in South Africa

• Published in: Journal of invertebrate pathology Vol. 111; no. 3; pp. 225 - 236
• Main Authors: Goble, T.A., Costet, L., Robene, I., Nibouche, S., Rutherford, R.S., Conlong, D.E., Hill, M.P.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01-11-2012; Elsevier
• Subjects: Agronomy. Soil science and plant productions; Animals; Beauveria; Beauveria - classification; Beauveria - genetics; Beauveria - isolation & purification; Biological and medical sciences; Biological control; Coleoptera - growth & development; Coleoptera - microbiology; Conidia; Fundamental and applied biological sciences. Psychology; General agroecology; General agroecology. Agricultural and farming systems. Agricultural development. Rural area planning. Landscaping; General agronomy. Plant production; Generalities. Agricultural and farming systems. Agricultural development; Genetic diversity; Genetics of eukaryotes. Biological and molecular evolution; Haplotypes; Life Cycle Stages; Microsatellite Repeats; Phylogeny; Population genetics; Population genetics, reproduction patterns; Saccharum; Scarabaeidae; Sequence Analysis, DNA; South Africa; Sugarcane/wattle agro-ecosystem; South Africa; Africa; Genetic diversity; Phylogeny; Population genetics; Sugarcane/wattle agro-ecosystem; Biological control; Scarabaeidae; Monocotyledones; Coleoptera; Taxonomy; Insecta; Sugar plant; Agroecosystem; Fungi; Beauveria brongniartii; Saccharum officinarum; Gramineae; Arthropoda; Angiospermae; Spermatophyta; Fungi Imperfecti; Invertebrata
• ISSN: 0022-2011; 1096-0805
• DOI: 10.1016/j.jip.2012.08.010

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► Beauveria brongniartii epizootics are occurring on the melolonthid species, Hypopholis sommeri. ► Low levels of genetic diversity have been detected in B. brongniartii isolates. ► Harden Heights and Canema may be considered one population over a distance of 5.5km. ► Historically, high levels of gene flow caused a lack of genetic differentiation between populations. ► B. brongniartii is being cycled from epigeal to subterranean environments.
Beauveria brongniartii (Saccardo) Petch fungal infections were observed on the melolonthid Hypopholis sommeri Burmeister (Coleoptera: Scarabaeidae) at two sites (Harden Heights and Canema) in the sugarcane producing area of the northern KwaZulu-Natal Midlands of South Africa. To initially identify the disease-causing fungus, 17 different fluorescently-labelled microsatellite PCR primers were used to target 78 isolates of Beauveria spp. DNA. Microsatellite data resolved two distinct clusters of Beauveria isolates which represented the Beauveria bassiana s.s. (Balsamo) Vuillemin (17 isolates) and B. brongniartii (60 isolates) species groups. These groupings were supported by two gene regions, the nuclear ribosomal Internal Transcribed Spacer (ITS) and the nuclear Bloc gene of which 23 exemplar Beauveria isolates were represented and sequenced. When microsatellite data were analysed, 26 haplotypes among 58 isolates of B. brongniartii were distinguished. Relatively low levels of genetic diversity were detected in B. brongniartii and isolates were shown to be closely related. No genetic differentiation was observed between the Harden Heights and Canema populations; they thus may be considered one, structured and fragmented population over a distance of 5.5km. Historically high levels of gene flow from swarming H. sommeri beetles is the proposed mechanism for this observed lack of genetic differentiation between populations. Microsatellite analyses also showed that B. brongniartii conidia were being cycled from arboreal forest to subterranean sugarcane habitats and vice versa in the environment by H. sommeri life stages. This is the first record of this species of fungus infecting H. sommeri larvae and adults in South Africa.