Biological Control 49 www.agrii.co.uk For specific advice and guidance on these and the other biological control options, contact your local Agrii agronomist. Whitefly The glasshouse whitefly (Trialeurodes vaporariorum) is a familiar pest, attacking a wide range of greenhouse crops. It feeds on the plant sap, reducing plant vigour and can multiply rapidly. It can also transmit viruses and the honeydew produced can encourage the growth of “sooty moulds”, which reduce the plants photosynthetic ability and may affect the quality of fruit and flowers. Increasing resistance of whitefly to chemical pesticides is making the use of biological control more important in the management of this pest. Some of the biological agents we can supply to control Whitefly include: Encarsia formosa Eretmocerus Aphids Aphids are small pear-shaped insects that vary in colour both within and between species. With their alarming rate of reproduction and increasing resistance to pesticides, they are becoming a much more serious threat to greenhouse crops. All aphids feed by inserting their stylets into the conducting vessels of the plant and feeding on plant sap. There are now effective aphid predators and parasites, and growers have started to rely on these for control. The biological control agent used can depend on several factors including pest levels and aphid species. Some of the biological agents we can supply to control Aphids include: Aphidius colemani Aphidius ervi Aphidoletes aphidimyza Aphelinus abdominalis Chrysoperla carnea