Regenerative biological control in Michigan certified organic greenhouses

Certified organic production in greenhouses presents interesting insect pest management challenges. The controlled environments in greenhouses and often continual availability of hosts results in a system that is prone to pest population explosions. Furthermore cosmetic standards for greenhouse produced bedding plants and produce are high with little tolerance for the presence of insects or insect damage. Traditional forms of biological control in greenhouses consist of augmentative releases of natural enemies in response to the detection of pests. In the last several decades researchers and greenhouse managers have become increasingly interested in open rearing systems that maintain natural enemy populations at high levels prior to pest invasion, thus intervening before pest populations rapidly increase. The two experiments presented in this poster examine spatial and temporal aspects of two open rearing systems. The first examines the rate of spatial spread of the aphid parasite Aphidius colemani from a centrally located banker plant, while the second examines the rate of population decay of the predacious mite Amblyseius cucumeris placed in "breeder piles". A better understanding of the spatial and temporal dynamics of open rearing systems will improve greenhouse growers' ability to economically manage pests using organically acceptable tactics.