Entomopathogens: Potential to Control Thrips in Avocado, with Special Reference to Beauveria bassiana

摘要

The South African avocado industry is an export-orientated, multibillion-rand (ZAR) industry, with approximately 3.0% of international market share and with a five-year annual average production of 118 000 tonnes from 17 500 ha. Forty percent of the harvested fruit is exported, 50% consumed domestically and the remaining 10% processed into oil and puree for both the domestic and export market. Being a predominately export-oriented industry, there is a commercial imperative to optimize the exportablepercentage of avocado fruit. Scarring damage by thrips results in corky tissue development, making the fruit unsuitable for export and potentially costing ZAR 160 million (16%) in lost export revenue. This review presents an assessment of the potential of a range of entomopathogens, including nematodes, viruses, fungi, and bacteria, but especially the entomopathogenic fungus, Beauveria bassiana, as potential biological control options for thrips control. B. bassiana is a natural occurring soil fungus that has been commercialized for the bio-control of several insect species including whitefly, weevils, aphids, thrips, and mealybugs on vegetable (potato, cabbage, kale), fruit (citrus, mango), and berry (coffee) crops. The use of B. bassiana for biological control of some insect pests is cost effective, and many strains are commercially available. The objective of this review is to highlight the potenital role fungi could play in insect control, to discuss commercially available mycoinsecticides and toevaluate the prospects of using entomopathogenic fungi as an alternative to synthetic chemicals to control thrips on avocado.