Abstract Model Greensys2007

The primary arthropod pests associated with greenhouse vegetable production in Florida are: broadmites, spider mites, thrips, aphids, and whiteflies. The primary disease is powdery mildew. The objective of this research was to identify pesticide-free control measures of the most common arthropod pests of the Florida greenhouse vegetable industry and to recycle water and nutrients, safely without disease pressure. 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 Aphidius colemani and Eretmoserus sp. 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, Amblyseius swirskii has been reported to be 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 pests is key to pest management and implementing biological control. Plants were fertigated in a hydroponic system using pine bark or perlite medium in nursery pots. Drainage water was collected, sanitized, adjusted for EC and pH when necessary, then recycled to the plants. A sustainable, pesticide-free environment is not only safer for the plants and produce being grown, but also, employee safety and efficiency can be increased since re-entry periods that delay worker production are eliminated. INTRODUCTION Demand for fresh vegetables in the United States has increased dramatically over the last 20 years (Pollack, 2001) forcing vegetable producers to compete in a worldwide market on a year round basis. In Florida, not only is global competition pressuring growers to consider alternative cropping systems, but pressures from urban development are restricting traditional farm operations and management. Harvested vegetable acreage in Florida declined 12.5% from 2003 until 2006 while annual value of production increased nearly $90 million to $1.9 billion (U.S.D.A-N.A.S.S., 2007). Grower efficiency and improved technologies will be necessary for producers to gain profitable returns now and in the future (VanSickle, 2007). Greenhouse structures can be located in areas less desirable for open-field vegetable production and away from urban encroachment or as evidenced in countries 1455 Proc. IS on Greensys2007 Eds.:S. De Pascale et al. Acta Hort. 801, ISHS 2008 such as Holland, Spain, and China, it can co-exist in an urban environment as well. The structures themselves can provide a barrier from pest intrusion and damage from wind, rain, and low temperatures. Especially in Florida, where production on sandy soil is prominent, water and fertilizers are frequently applied to open-field production with potential leaching into ground water. Improved irrigation and fertilizer technologies used in protected agriculture appropriately regulate water and fertilizer use to fulfill plant requirements and all excess is collected and recycled. Pesticide use has become a large focus for growers trying to satisfy consumer demands for safe food and a clean environment. Pest management under greenhouse conditions is improved by using anti-virus exclusion screens, worker entry disinfection zones and UV-blocking polyethylene coverings. Furthermore, pest management is enhanced by using an integrated pest management (IPM) strategy that includes timed releases of beneficial organisms, banker plant habitats (Osborne and Barrett, 2005; banker plants in detail: mrec.ifas.ufl.edu/lso/banker/banker.htm), and using pesticides with low residues which specifically target a pest species. The primary arthropod pests associated with greenhouse vegetable production in a closed-system in Florida are: mites, western-flower thrips, aphids, and whiteflies. The primary disease is powdery mildew. The University of Florida Protected Agriculture Project (UFPAP, www.hos.ufl.edu/protectedag) initiated hydroponic, vegetable research in a high-roof passively-ventilated greenhouse in spring 1999 (Gainesville, FL). During the first year, chemical pesticides were used to control both insect pests and disease. Several vegetable species were grown, subsequently, pest issues varied between the crops. Pesticide application was labor intensive, repetitive, and difficult to uniformly apply due to the dense planting system. Plants and fruit were damaged or burned by both the chemical and means of application (gasoline powered sprayer). Few chemical pesticides were registered for use in the greenhouse, therefore, rotation among chemical types was difficult and pest resistance was certain. Alternative pest control measures were necessary and IPM strategies were adopted. Releasing beneficial insects is user friendly, as personal protective equipment required for chemical application is not needed, re-entry times are eliminated, and employees can continue to work during the release. During the first few seasons of relying on natural enemies we learned many key lessons including 1) predators and parasitoids will not eliminate pests; 2) pest populations must be below threshold levels for beneficial arthropods to be effective; 3) chemical pesticides must be specifically selected in an IPM program as most chemicals which target pests will also kill natural enemies and bumble bee pollinators; 4) beneficial arthropods should be released at planting or prior to pest infestation; 5) scouting, record keeping, and proper identification of pests, disease, and biological agents are key to a successful IPM program. Since October 2003, research has been conducted in similar structures in Citra, FL where IPM strategies were implemented during the first growing season. The objective of this research was to identify pesticide-free control measures of the most common insect pests of the Florida greenhouse vegetable industry, including the crops tomato (Rodriguez et al., 2001), pepper (Jovicich, 2007; Jovicich et al., 2004a, b), strawberry (Paranjpe et al., 2003; Rondon et al., 2004a, b), muskmelon (Mitchell et al., 2007; Shaw et al., 2001), squash (Shaw and Cantliffe, 2005) and cucumber (Shaw and Cantliffe, 2003) in a sustainable, recycled water and nutrient system. GREENHOUSE STRUCTURE AND PEST PREVENTION The UFPAP located in Citra, FL, consists of two equal passively-ventilated 0.41ha structures (Top Greenhouses Ltd., Barkan, Israel). Each sidewall was 4.2 m high. Each of five bays within both structures has a 1.5-m roof vent located at 4.2 m, for a total roof to floor peak of 5.7 m. The structure was covered with single layer, 8-mil polyethylene (PE) plastic (Sun Selector UVA, Ginegar Plastic Products, Ltd., Kibbutz Ginegar, Israel). The PE covering used was selected for its anti-fog additives as well as UV absorption qualities. The anti-fog plastic reduces damage to the plants from eliminating falling water droplets and also, the reduction of moisture in the greenhouse diminishes development of