THE EFFECT OF THE GREEN ANT, OECOPHYLLA-SMARAGDINA (HYMENOPTERA, FORMICIDAE), ON INSECT PESTS OF CASHEW TREES IN AUSTRALIA

The influence of green ants, Oecophylla smaragdina (Fabricius), on ins ect pests of cashew, Anacardium occidentale Linnaeus, in tropical nort hern Australia was investigated using field surveys and field observat ions. Oecophylla smaragdina was abundant in the native vegetation of t he area, and it was a dominant predator when found in cashew plantatio ns. Oecophylla smaragdina significantly reduced the numbers of the fou r most important species of insect pests (Helopeltis pernicialis Stone dahl, Malipatil & Houston, Penicillaria jocosatrix (Guenee), Amblypelt a lutescens (Distant) and Anigraea ochrobasis Hampson) on cashew trees , and trees with higher numbers of O. smaragdina produced higher quali ty nuts than trees with fewer numbers of 0. smaragdina. Other ant spec ies also reduced pest numbers, but not as much as 0. smaragdina. The p ossibility of using 0. smaragdina to control insect pests of cashew in the future is discussed.