Alternative Food Sources to Predatory Mites (Acari) in A Jatropha Curcas (Euphorbiaceae) Crop

Abstract

In Brazil, smallholders produce the physic nut Jatropha curcas in association with crops such as pumpkin and corn, besides weeds. We evaluated the suitability of pumpkin and corn pollens, as well as pollen from a weed species (Peltaea riedelii), present in physic nut crop, as alternative food to predatory mites Euseius concordis and Iphiseiodes zuluagai. These species are natural enemies of Polyphagotarsonemus latus and Tetranychus bastosi, two important mite pests on J. curcas plants. The survival and oviposition rate of E. concordis and I. zuluagai were evaluated for five days on leaf discs supplied with pollen of pumpkin, corn or P. riedelii. Castor bean pollen (Ricinus communis) was provided to the predators as a control of suitable food. No significant difference on the oviposition rate of both I. zuluagai and E. concordis was observed when they fed with pollen from the three plants. However, the source of pollen affected the survival of the predatory mites. Pumpkin pollen was the worst food for both predatory mites while corn and P. riedelii was a better food. These results indicate the non-suitability of pumpkin pollen as alternative food to I. zuluagai and E. concordis. Corn and P. riedelli are sources of supplementary food to the predatory mites and can sustain predator populations when prey is scarce.