Integrating chemical and biological control in gerbera production

Lyriomyza trifolii is the important leafminer and primary pest in the Gerbera system. Being resistant to almost all pesticides, presents significant challenges in the control of this leafminer species. Effective biocontrol agents are available for controlling leafminer populations, but influx of secondary pests like mites, thrips, aphids and whiteflies complicate control strategies. In this series of experiments, we evaluated plant protection chemicals for their safety to leafminer parasitoid Diglyphus isaea and predatory mite Neosieulus californicus. Many of the commonly used chemicals were found to cause high mortality of natural enemies. Avid caused high mortality in beneficials while Conserve was even stronger, even though both are important in controlling mites and thrips respectively. We will have to reassess our control strategies if greenhouse gerbera management depends on Biocontrol.