Banana plants are more readily infested by Raoiella indica (Acari: Tenuipalpidae) when surrounded by infested coconut palms

Raoiella indica Hirst, the red palm mite (RPM), is an invasive pest first reported in Puerto Rico in late 2006. RPM populations are spreading through the neotropics and causing severe damage in its primary host, coconut (Cocos nucifera). Other plants, including Musa, are also affected, mainly when growing nearby coconut palms. We carried out a greenhouse study using potted plants of banana and coconut palms to determine the effect of the ratio of coconut palms to banana plants on the RPM densities on banana. For this study we used two treatments: 1- one banana plant to four palms infested with RPM (1:4); 2- four banana plants and one RPM infested palm (4:1). The single plant was placed in the middle. RPM on banana plant leaves were counted monthly for 4 months. In addition, under each banana plant’s second expanded leaf a Petri dish with water was set for 48 hrs to trap any falling RPM’s. Higher densities of RPM were found on banana plants that were at a 1:4 ratio to the palms. In another study we evaluated the efficiency of acaricides for control of RPM in bananas. The tested products were sorbitol octanoate, sucrose octanoate esters, bifenozate, hexythiazox, acequinocyl, spiromesifen and etoxazole. Each treatment consisted of five plants and a control, which was sprayed with only water. Mites on the second expanded leaf from each plant were counted at three, seven, twelve and eighteen days after spraying. Acequinocyl and spiromesifen were the most effective products for reducing the RPM population.