Urban Ag Issue 4, Dec 2013 | Page 15

“Growers considering aquaponics, which combines the raising of fish with plants, need to keep chemical applications at a minimum. Most pesticides cannot be used in an aquaponics system. This is a major consideration when growers think about this type of production system. Under these circumstances a grower would want to look at what he can do with cultural controls and natural enemies where there is no risk of anything getting into the water with the fish. This would also be the case with the growing of medicinal plants.” Tifft said based on her experience with the typical horticultural and agricultural crops there is going to be a place for pesticides for a long time. Biological controls for insects Tifft said most of the large greenhouse tomato growers in the United States and Canada are using natural enemies for insect control. She said in most of these operations the use of natural enemies is standard operating procedure. “The use of these biological controls has become easier because they have been well researched,” she said. “There are effective natural enemies and reliable suppliers with good distribution networks which can deliver the biologicals overnight.” Tifft said the use of natural enemies can be more difficult for the small grower because the cost of shipping can be prohibitive. “For vegetable growers it has become selfPhoto by Adelyn Photography evident to many of them Karin Tifft is working with a grower to evaluate the use of that they need to break banker plants to determine the feasibility of producing a “Most natural enemies the cycle of pests and steady supply of natural enemies for aphid control. need to be shipped diseases by emptying and overnight,” she said. thoroughly cleaning the “For small growers, the greenhouse,” she said. “I cost of shipping may have seen several cases be higher than the cost where insect or disease for the amount of prodproblems have gotten out uct that’s needed. And of control and there was there usually is no way no way to manage the for growers to store the problems other than to natural enemies without clear out the greenhouse. dramatically reducing This may have occurred their efficacy. They have because of a change made to be used right away.” to the IPDM platform. This could include a Tifft is currently worksudden drop in natural Photo courtesy of IPM Laboratories ing with a small vegeenemies or application table grower to evaluate of certain chemicals or because the correct action the option of using banker plants to determine the was not taken in a timely manner. The growers then feasibility of producing a steady supply of natural attempted to do everything they could within the enemies. She said the banker plant system that is most established is for aphid control. limits of the product labels, but weren’t successful at gaining control.” Cereal aphids are introduced into the greenhouse 15