Evaluation of the Efficiency of Two Plant Extracts for the Citrus Brown Mite Eutetranychus orientalis (Acari: Tetranychidae)

Abstract

The citrus brown mite, Eutetranychus orientalis (Klein), is one of the most injurious pests of fruits, vegetables and ornamental plants worldwide. The objective of this study in order to evaluate the repellency and toxicity effect of two essential oils against E. orientalis. Essential oils were extracted of aqueous extracts from rosemary, Rosmarinus officinalis L. herbs and coriander, Coriandrum sativum L. fruits. Five concentrations 0.5, 1, 2, 3 and 4% were used for each essential oil. The chemical composition of the essential oils was characterized by GC. The results indicated that there were significant differences in efficiency of the tested essential oils on the developmental stages of E. orientalis. The coriander was the most toxic for controlling the egg stage, larval, nymphal and adult stages of E. orientalis than rosemary. Coriander oil was the most potent oil tested eggs (LC50= 1.26 and LC90= 4.82), while rosemary oil were the least toxic oil tested on eggs (LC50=1.49 and LC90=7.94%) after 7 days. The LC50 were 0.16& 1.71, 0.21& 1.09 and 0.77& 4.41% for larvae, nymph and adult females for coriander and rosemary, respectively. Thus, the coriander essential oil became more effective than rosemary with increase in the doses. Moreover, the coriander oil is highly repellency effect than rosemary on female E. orientalis. The results suggest that coriander and rosemary essential oils and its two major constituents Linalool and camphor can potentially be used for the management of E. orientalis.