Greenhouse Production of Vegetable Crops Grown with a Recycled Fertigation System in a Pesticide-free Environment
Daniel J. Cantliffe1, Nicole L. Shaw1, Elio Jovicich1, Lance S. Osborne2, and Peter J. Stoffella3
1Horticultural Sciences Department, University of Florida, P.O. Box 110690, Gainesville, FL 32611, USA, ; . 2Mid-Florida Research and Education Center, 2725 Binion Rd., Apopka, FL 32703 USA, . 3Indian River Research and Education Center, 2199 S. Rock Rd, Ft. Pierce, FL 34945, USA, .
Keywords: biological control, integrated pest management (IPM), pepper, cucumber, muskmelon
Abstract
Vegetable crops were valued at nearly $1.9 billion during 2005 in Florida. Field growers rely on methyl bromide and chemical applications of insecticides and fungicides throughout the season to insure high crop yields. Vegetable growers in Florida are faced with pressures from urban areas for land use as well as pesticide drift. Greenhouse production is an alternative scheme to reduce land use, allow production in less desirable areas or less productive land, and allow for efficient production schemes including recycling unused fertilizer and irrigation water. Greenhouse production cannot only increase yield per area, but the structure can serve as a barrier from insect pressures using anti-virus exclusion screens, worker entry disinfection zones, and UV blocking polyethylene coverings that interrupt pest reproduction cycles. Pest management is thus enhanced by using timed releases of biological control insects, banker plant habitats, and an IPM strategy that includes no pesticide applications with residual effects on the beneficials in use, including bumble bees. The primary insect pests associated with greenhouse vegetable production in a closed-system in Florida are: broadmites, spider mites, thrips, aphids, and whiteflies. The primary disease is powdery mildew. The objective of this research is to identify pesticide-free control measures of the most common insect pests of the Florida greenhouse vegetable industry. The University of Florida Protected Agriculture Project has successfully implemented the use of several biological control schemes which control these pests. Beneficial insects must be introduced prior to pest infestations and releases are generally made at transplanting and repeated twice during initial crop growth. Banker plants, most often a monocot species, are introduced at transplanting to rear an additional food source and serve as a habitat for beneficial insects by maintaining a pest population that is specific to the host banker plant which in turn the beneficial insects can feed and reproduce on. Broadmites and spider mites are controlled with the predatory mite N. californicus if released prior to or at transplanting. Aphids and whiteflies are controlled with the parasitic wasps A. colemani and Eretmoserus or Encarsia sp., respectively, which can be released and/or reared on banker plants. Thrips populations can be reduced with generalist predators such as Orius sp., but more recently a predatory mite, A. swirskii has been shown effective. Disease resistant cultivars are preferred, however, cultural controls such as isolation from disease pressure, anti-condensation coverings, fans and aeration and bio-friendly fungicides are necessary. Regular scouting and correct identification of insects is key to pest management and implementing biological control. A pesticide-free environment is not only safer for the plants and produce being grown, but also, employee efficiency can be increased since re-entry periods that delay worker production are eliminated.