NATURAL ENEMIES OF CITRUS RED MITE (PANONYCHUS CITRI) IN CITRUS ORCHARDS

摘要

Citrus red mite (CRM) populations can reach high levels in citrus orchards after the application of broad-spectrum pesticides to control other pests. It is important to know which are the key biocontrol agents of CRM in New Zealand in order to minimise use of pesticides toxic to these natural enemies. CRM and natural enemies were monitored in seven orchards from January 2004 to March 2005. Ladybirds, Stethorus sp. and Halmus chalybeus, and predatory mites, Agistemus longisetus, Amblyseius largoensisand Phytoseiulus persimilus, were observed consuming CRM. Stethorus sp. and A. longisetus were the most abundant natural enemies found with CRM. The presence of 0.5 live Stethorus sp. per leaf and 0.5-1 A. longisetus per leaf was associated with the decline of CRM populations (15 eggs and 15 juvenile/adults per leaf) to 'trace' levels in 4-5 weeks. The use of neonicotinoid products can disrupt the predatory activity of Stethorus sp. against CRM.