Populations of the citrus red mite, Para-tetranychus citri, often decrease rapidly when climatic conditions are apparently favorable and natural enemies are extremely scarce. Leaf injury caused by the feeding of the mites is shown to be a factor capable of causing this reduction. Within the density ranges tested there was no direct influence on the oviposition attributable to the number of mites per cage, the reduction being due to the resulting feeding injury. There was a slight increase in mortality associated with feeding injury. The reduction in egg production associated with leaf injury was not due to any toxic condition transmissible from one portion of the leaf to another. The numbers of eggs produced on young and medium-age leaves were greater than on old leaves. Feeding injury influenced egg production to a much greater extent on flush-growth leaves than on the older leaves.