Ultraviolet blocking greenhouse polythene covers for insect pest control on organic crops: May 2003 - September 2004

Summary

This report reviews the development work carried out within the ‘UV Blocking Polythene Trial’ on the organic farm at the Welsh College of Horticulture during the period May 2003 to September 2004. Two tunnels were erected in 2003, one covered in UV blocking ‘Sterilite’ film and the other in the non-UV blocking ‘Super Strength 600’. The salad/brassicas crops grown during the first season under the UV blocking film showed significantly less pest attack (both winged and non-winged pests). Less aphids were present and their ‘flight behaviour’ was greatly reduced under the UV blocking film. The crops under the UV blocking film also appeared to establish quicker and reached a greater final size. Two more tunnels were erected in spring 2004 and covered in identical films. All four tunnels were then cropped with tomatoes, peppers and cucumbers. The level of pests in all crops/tunnels was generally very low during the season and there was no apparent significant difference in pests under the two different films. Blue and yellow sticky traps caught noticeably more insects under the non-UV blocking film and this highlighted either a greater population level, and/or an increased level of flight activity under that film. The report draws conclusions from the trials and makes recommendations for the 2005 research.