A comparison of the toxicity of two commercial botanical extracts and two synthetic insecticides on Chromaphis juglandicola (Hemiptera, Aphididae)

Walnut is one of the most important fruit trees in many parts of the world cultivating. In recent years, walnut aphid Chromaphis juglandicola (Kaltenb) (Hemiptera, Aphididae) is known as a serious pest of Persian walnut (Juglans regia L.) in Iran and other parts of the world. Recently, the damage of the pest increased high on walnut trees in Bavanat region, northern Fars province, Iran. Effect of some pesticides on the pest was studied during growing season of 2014 in Bavanat. An experiment was performed in a Completely Randomized Block Design with treatments including coconut botanical soap (Palizin® SL70%, 2000 ppm), garlic extract (Sirinol® EC80%, 2000 ppm), imidacloprid (Confidor® SC35%, 750ppm) and hexaflumuron (Consult® EC10%, 750ppm) and control with 4 replications. Samplings were conducted before spraying and five times after the spray at 3, 7, 12, 18 and 21 days interval. Based on the results on days of 1, 3, 7, 12, 18 and 21 after spraying, imidacloprid had the highest and coconut oil soap had the lowest effect on walnut aphid. As a result, imidacloprid is the most effective compound to control walnut aphid. However, garlic extract can be recommended as alternative compound with low hazard on environment and human health.