Intercropping potato with citrus trees as ecologically–based insect pest management

Potato can be cultivated on various environments in different seasons, which makes it vulnerable to numerous insect pests. The presence of various types of insect pests may hinder the pest management with pesticides. Intercropping system provides an alternative nonchemical option for controlling insect pests. This study was carried out to evaluate the usefulness of intercropping potato under sweet orange Citrus sinensis trees. For this purpose, densities of four main sap–sucking insect pests and their natural enemy predators were examined in two cultivation seasons. The results indicated that the intercropping system could be a useful technique for using space under citrus trees. The intercropping system significantly reduced the infestation of whitefly Bemicia tabaci though the density of green peach aphid Myzus persicae rather increased. Planting systems also had a significant but minor impact on potato leafhopper Empoasca fabae and green sink bug Nezara viridula. Beside, the pest occurrence differed markedly between summer and winter potato fields. Natural enemies such as ladybeetle Coccinella undecimpunctata densities were greater on intercropping than mono–cropping potato in both winter and summer seasons but Orius insidiosus was rather fewer in intercropping systems. Our study suggests that the intercropping system is useful in pest management of potato.