The effects of farming system, habitat type and bait type on the isolation of entomopathogenic fungi from citrus soils in the Eastern Cape Province, South Africa T. A. Goble • J. F. Dames • M. P Hill • S. D. Moore Received: 3 June 2009 / Accepted: 23 November 2009 / Published online: 11 December 2009 Ó International Organization for Biological Control (IOBC) 2009 Abstract A survey of occurrence of entomopatho- genic fungi was undertaken on soils from citrus orchards and refugia on conventionally and organi- cally managed farms in the Eastern Cape Province in South Africa. An adapted method for baiting soil samples with key citrus pest Thaumatotibia leucot- reta (Meyrick; Lepidoptera: Tortricidae) and Cerati- tis capitata (Wiedemann; Diptera: Tephritidae) larvae, as well as with the standard bait insect, Galleria mellonella (Linnaeus; Lepidoptera: Pyrali- dae), was implemented. Sixty-two potentially useful entomopathogenic fungal isolates belonging to four genera were collected from 288 soil samples, an occurrence frequency of 21.53%. The most fre- quently isolated entomopathogenic fungal species was Beauveria bassiana (Balsamo) Vuillemin (15.63%), followed by Metarhizium anisopliae var. anisopliae (Metschnikoff) Sorokin (3.82%). Galleria mellonella was the most effective bait insect used to isolate fungal species (v 2 = 40.13, df = 2, P B 0.005), with a total of 45 isolates obtained, followed by C. capitata with 11 isolates, and T. leucotreta with six isolates recovered. There was a significantly (v 2 = 11.65, df = 1, P B 0.005) higher occurrence of entomopathogenic fungi in soil samples taken from refugia compared to cultivated orchards of both organically and conventionally managed farms. No significant differences were observed in the recovery of fungal isolates when soil samples from both farming systems were compared. Keywords Thaumatotibia leucotreta Á Ceratitis capitata Á Natural occurrence Á Galleria bait method Introduction The South African citrus industry is the second largest exporter of citrus worldwide after Spain (FAO: Citrus Fruit Annual Statistics 2006). Annually, up to 89 million cartons of citrus fruit are exported, generating an annual income of approximately ZAR 5.1 billion for South Africa (Edmonds personal communication). As a result of the European Union’s strict phytosanitary regulations, and drive to reduce harmful chemical pesticides (Mather and Greenberg Handling Editor: Helen Roy. T. A. Goble (&) Á M. P Hill Department of Zoology & Entomology, Rhodes University, P.O. Box 94, Grahamstown 6140, South Africa e-mail: m.hill@ru.ac.za J. F. Dames Department of Biochemistry, Microbiology & Biotechnology, Rhodes University, P.O. Box 94, Grahamstown 6140, South Africa S. D. Moore Citrus Research International, P.O. Box 20285, Humewood, Port Elizabeth 6013, South Africa 123 BioControl (2010) 55:399–412 DOI 10.1007/s10526-009-9259-0