Repellence and Anti-oviposition Activities of Plant Products on Greenhouse Whitefl y

Introduction: The greenhouse whitefl y, Trialeurodes vaporariorum Westwood (Homoptera: Aleyrodidae), is an important cosmopolitan pest of many crops. Methods: The present study investigated the repellent and antioviposition activities of plant products from Achillea millefolium and Thymus vulgaris against this pest in greenhouse conditions. Cucumber plants were sprayed with the chemicals at 40 μl/ml concentration and control plants were treated with distilled water. Also, the essential oil of A. millefolium at the same volume (5 ml) was sprayed on the special fi lter paper (2×4 cm) attached at the petiole plant. Four treated plants and four control plants were placed randomly in to a cage. Three days after spraying, approximately 250 whitefl y adults were released into the cages. Then three and six days after infesting, the number of eggs and adults were recorded. Each experiment was repeated two times at the same greenhouse condition. Results: The results revealed that all plant products affected the oviposition and tropism behaviors of greenhouse whitefl y. Amongst the different treatments, the highest anti-oviposition effect was calculated by aqueous extracts of T. vulgaris (62.87%) six days after treated. Moreover, the aqueous extract of A. millefolium had the highest repellent effect (52.54%) six days after treatment. Also, the compare repellent activity of the chemicals on greenhouse whitefl y adults indicated the highest repellent effect was evaluated by the essential oil of A. millefolium (48.07%) nine days after treatment. Conclusion: These results showed that A. millefolium and T. vulgaris had relatively

long lasting repellent and anti-oviposition activities on the adults of the greenhouse whitefl y.