Polyphagy in the Australian population of South African citrus thrips (Scirtothrips aurantii Faure)




The South African citrus thrips, Scirtothrips aurantii Faure, 1929, is highly polyphagous in its country of origin. Introduced to Australia in about 2002, populations of this thrips have been found only on the pasture weed Mother of Millions, Bryophyllum delagoense (Eckl. & Zeyh.) 1900. To evaluate the potential risk by these populations to plants of economic significance, under laboratory conditions, whether S. aurantii collected from Mother of Millions in Queensland can survive, reproduce and maintain populations over multiple generations on non-target hosts was tested. That this thrips can form self-sustaining populations on mango, grape, chilli, pea, green bean and blueberry was showed. Extended adult lifespan and some juvenile production were found on lemon and orange, but populations did not persist on these hosts. Furthermore, female thrips accept mango and grape for oviposition as readily as Mother of Millions. This degree of polyphagy under laboratory conditions suggests that caution is needed before promoting this thrips as a biocontrol agent against the pasture weed.