2017 ASHS Annual Conference

The use of beneficials/biologicals/predaceous mites can be intriguing in a controlled research experiment and the idea, marvelous, but it is a different ball game for the grower who has to use them under prevailing natural conditions while envisaging positive results. Most growers who follow Integrated Pest Management strategies express the need of incorporating the use of biologicals, especially in high tunnels which are semi-enclosed structures. The major objective of this project was to implement the use of predacious organisms for control of whiteflies, thrips, spider mites and aphids in tomato, pepper, eggplants, cucumbers, strawberries, and collard greens grown in high tunnels. Note that these are not replicated trials but important real life observations during implementation of use of biologicals. We released; predaceous mites, Amblyseius swirskii, and Neoseiulus carlifornicus, parasitic wasp; Aphidius colemani and parasitoids in the genera Encarsia and Eretmocerus in seven high tunnels in four different locations in Delaware (Smyrna, Hartly, Townsend and Seaford). The project went on for 3 years (2013 to 2016) during the growing season between May to September during which we monitored insect pests’ counts and populations of predators on plant leaves, and on yellow and blue sticky cards. We monitored temperatures and humidity in the high tunnels using hourly temperature and humidity tracking devices (onset Hobo data loggers) suspended inside the high tunnels. We documented as much as possible, the prevailing conditions in the high tunnels at the time of release. The IPM Laboratories, Inc. (Locke, NY 13092) bred and delivered the biologicals directly to the locations nearest to the location of use in Seaford, DE and Dover, DE. Results obtained were both negative and positive and varied with location. A. swirskii, kept the whitefly (B.tabaci) and broad mites (P. latus) populations low in the Townsend location, N. carlifornicus adequately controlled spider mites on pepper in Hartly. A. colemani was effective on aphids on tomatoes at the Seaford location although there was substantial presence of lady bugs. Many factors could have contributed to the results namely; Time of release in relation to weather and plant stage of growth or growth season; level of pest infestation; predator persistence; availability of alternative food sources etc. It is difficult to gauge the possible interactions between the predators sharing an ecological niche. More trials and guidance is needed for use of beneficials in semi enclosed and open fields for more effective results by growers.