Citrus Insect Interactions: Implications for Pest Management

Abstract

We observed that insect interactions lead to damaged fruits, leaves, stems, and exposed fruits and tree trunks to pathogenic infection, however, some citrus trees were protected by these interactions. Our study shows that Oecophylla longinoda and Crematogaster spp. protect citrus aphids and citrus scale insects from their natural enemies leading to their outbreak and further damage to the citrus plant. Citrus trees with more Oecophylla and Crematogaster had fewer pests such as fruit flies, termites and the variegated grasshopper, Zonocerus variegatus. Our study shows that “chain” formation by weaver ants, Oecophylla enables them to reach the same colony in different citrus trees. We identified wild passion plant, Passiflora sp. as an alternate host for Leptoglossus spp. We recommend Oecophylla and Crematogaster as biological control agents against fruit flies, termites and the variegated grasshopper; however, they could lead to an outbreak of citrus aphids and citrus scale insects. Phasmomyrmex aberrans is antagonistic to Oecophylla and so in an attempt to utilize Oecophylla as a biological control agent, we recommed that care must be taken to ensure that they do not come together. As biological control agents in orchards that do not have closed canopies, we recommend that sticks or ropes be connected to adjacent trees to facilitate movement of the ants to enhance their dispersal in orchards. Care must be taken to clear all Passiflora sp. from citrus orchards.