Feeding on Different Types of Pollen Enhances Suitability for Release of the Red Mite as a Biological Control Agent Against a Variety of Plant Pests

Indianapolis, IN

The red mite Balaustium murorum, readily consumes aphids, scale insects, white flies, spider mites, and their eggs, making this mite useful in classical biological control programs. This mite is also a pollen-feeder, switching from pollen to prey as prey becomes available through the spring. This study tests the hypothesis that specific plants may dictate where red mites establish, which may be important where these mites could be used for plant pest control. Accordingly, mites in six-sector Petri plate attraction bioassays with pollen that was collected from different plants and then staining the pollen with Evans blue as a tracer was used to examine feeding rates. All mite stages (larvae, deutonymphs, and females) ingested pollen grains whole, as evidenced by blue coloration in the gut, and from a variety of sources: tulip, pear, maple, crabapple, viburnum and narcissus cultivars. Larvae were the most aggressive feeders, based on speed of clearance of piles of pollen, amount consumed, and number of mites feeding on pollen at any one time; activity by deutonymphs and females was not as vigorous. There was no positive attraction to fed mites, thus suggesting that mites encounter pollen at random and not by an aggregation pheromone released by others. The conclusion of this experiment is that many pollen-producing plants can contribute toward setting up these mites in a new geographic application.