Finding new avenues for its use
Over the years, in an attempt to make food both plentiful and inexpensive, agribusiness has developed pesticides and fungicides to improve fruit and vegetable production around the world. In some cases, these synthetic chemicals have been used with the belief that any economic and ecological problems they might cause would be far outweighed by the benefit of increased food and fiber production. As a result, we’ve come to accept the use of synthetic chemicals in agriculture as normal. However, the overreliance onsynthetic pesticide use in crop production has resulted in disturbances to the environment, pest resurgence, pest resistance to pesticides and toxic or lethal effects on nontarget species, including humans.
In the immensely diverse bio-system humans must share with other species, competition with those creatures we call pests is an unavoidable reality in farming. Agricultural pests are costly, reducing the yield of crops, resulting in less food for the world’s masses while increasing the cost of those crops due to the added inputs necessary to grow them. With the world’s population increasing by thousands each day, farmers strive to attain the greatest yield of fruits and vegetables from a given amount of acreage. At the same time, population increases are now placing greater demands for clean air, water and wildlife habitat—all while farmers are expected to increase crop outputs. Both commercial agribusiness and the home gardener are faced with the challenge of how to deal with crop pests in a cost-effective and ecologically responsible and friendly manner.
Recognizing that agribusiness must develop a system of pest management that reduces the arbitrary use of pesticides for many applications has led to the creation and implementation of integrated pest management systems, or IPM. The heart of an IPM strategy proposes to manage pests through an understanding of their interactions with other organisms and the environment. The general focus of IPM programs is to prevent pest problems from developing while at the same time reducing or eliminating the use of pesticides and other chemicals as a way of managing those problems. IPM programs have been instrumental in increasing people’s awareness of how fragile our environment is and the responsibility farmers have in reducing the impact of pesticides on the environment. IPM seeks to restore and enhance the natural balances in an eco-system and not to necessarily eliminate species. Regular monitoring makes it possible to evaluate the populations of pest and beneficial organisms. IPM allows a producer to take steps to enhance natural controls—or at least avoid or limit the disruption of natural controls—of the target pests.
In the United States, the first environmental laws were enacted in the 1970s, focusing primarily on water and habitat conservation. Realizing that farming and food production must continue, both the federal and state environmental agencies along with USDA have provided funding to farmers and university extension services to implement IPM programs throughout the country. The University of Connecticut, Storrs, Conn., has several IPM programs working with fruits, vegetables, green-houses and nurseries.
Lorraine Los is an IPM coordinator specializing in fruit crops at UConn’s College of Agriculture and Natural Resources. She says that IPM incorporates a number of different approaches specifically directed to address a particular pest problem. For example, IPM may utilize cultural controls. One example involves the removal of certain plants that are the source of a disease for a particular fruit. Cedar Apple Rust is a problem for the apple crop, she says. Cedar trees should be removed from around an apple orchard to control that particular blight. In the case of cucumbers, mechanical controls can be put in place by placing row covers on cucumber plants so that the cucumber beetle can’t get at them. In each case, the use of pesticides is reduced.
Biological controls involve the release of specific predators or parasites that can attack a particular pest, or preserving the pest’s natural enemies that are already out there. Los noted that there are two dozen pests just for the apple crop alone. She described one example in which a predatory mite, Typhlodromus pyri, was released that feeds on the European red mite, a serious apple pest. This predatory mite is more tolerant of pesticides, giving it a higher survival rate in the orchard than the native red mite.
Every type of fruit has its own unique set of challenges during the growth process. If the application of a pesticide is needed, Los works with her fruit growers to determine the best choice and timing of a pesticide once an action threshold has been reached for a pest. The IPM program enables growers to be able to recognize and learn how to conserve the many beneficial native predators and parasites in their fields and orchards.
Los also maintains seven weather stations at various locations in Connecticut that measure temperature, humidity, leaf wetness and rainfall. She uses the data to help with disease and insect forecasting. Diseases such as apple scab, a fungus, and fire blight, a bacterial disease, are dependent upon degree days and leaf wetness. In other words, they don’t emerge the same time each year, but are dependent upon temperature and moisture. The stations enable her to help forecast when growers might expect them to occur in the state.
The existence of the IPM program at UConn is dependent upon outside funding. The Connecticut Department of Environmental Protection (DEP) has provided funding for many years through their Section 319 Nonpoint Source Pollution Grants. Since 2002, the UConn IPM group has focused IPM grower education on the Thames River Basin, which covers approximately the eastern third of the state.
The IPM group is also involved with the USDA Natural Resources Conservation Service (NRCS) program called EQIP (Environmental Quality Incentives Program). There are many practices involved in EQIP including IPM. To receive funding through EQIP, growers must apply to the program and are then chosen to participate by NRCS. They sign a three-year contract, and then the IPM group receives funding and becomes the “Technical Service Provider,” providing the training to develop an IPM plan on the farm.
Ana Legrand, IPM funding coordinator at UConn, says the IPM program also relies on grants to support staff salary and a Web site, as well as obtaining materials for research or extension projects. She notes that funding can vary from year to year and the team must compete for limited amounts of money available either at the regional or national levels. The grants received for IPM are not “automatic” funds and the team members have been successful in obtaining grants for their salaries or to run programs.
Jude Boucher, commercial vegetable crops specialist with UConn Cooperative Extension, describes IPM as an educational process and information-gathering system that teaches crop growers how to minimize pesticide use. He, too, works with Connecticut growers through DEP and EQIP programs. During the three-year contract time that a grower commits to EQIP, all the IPM specialists work closely with their growers, making weekly visits the first year, setting the groundwork for the IPM plan. They continue to monitor with periodic follow-ups over the next two years.
During the growing season, which begins in April, Los and Boucher are heavily involved with the field aspects of IPM. They work one-on-one with their growers in scouting and monitoring their crops. One of the goals of IPM is for the growers to eventually be able to take care of much of the work themselves.
IPM programs continue to evolve based upon challenges that develop in the field. Boucher has been working for some years on perimeter trap cropping (PTC), which involves planting an attractive plant species (to the pest) so that it completely encircles the main crop like a fortress wall. PTC functions by concentrating and/or killing the pest in the border area, while reducing pest numbers and disease spread on the unsprayed cash crop in the center by preserving natural enemies. In one example in 2002, blue hubbard squash was planted around yellow summer squash. The pests that were damaging the yellow squash crop were more attracted to the blue hubbard. Spraying only the perimeter crop significantly reduced the pest to the summer squash and the need to spray an entire field. Boucher noted that six commercial growers successfully employed the technique that year.
In 2006, Los began working with Maple Lane Farm in Preston, Conn., which is the largest grower of black currants (75-plus acres) in North America. She discovered that the most serious pest affecting the black currant in Connecticut is the currant borer, which bores into the stems and can kill the plants. Los has been experimenting with the use of insect pheromones as a mating disruptor for this pest. The premise of this research is that if you inundate a field with the pest’s pheromone, the males and females can’t find each other to mate and lay eggs.
Boucher has also been working with growers in reduced tillage programs, which are being promoted to correct soil problems, slowing down the depletion of organic matter in fields. Over time, the structure and other physical characteristics of soil tend to be compromised with the continuous plowing of fields or the compaction of seed beds. As soil quality diminishes, crop yields will decline. Using alternative methods of soil preparation—making the soil healthy again—will also help in the reduction of pesticides and fungicides.
Legrand also says that UConn has an active outreach program dealing with invasive plants and they are seeking ways to expand the IPM program offerings for nursery and turf managers. She adds that the number of growers receiving IPM training depends upon how many IPM staff are employed at the time. In 2005, 33 growers received full-season IPM training programs. Since the beginning of the program in 1980, they have provided 771 full-season, one-on-one trainings. They also reach a larger audience through public workshops, conferences and twilight meetings. Their Crop Talk newsletter goes to a mailing list of over 800 recipients, and the IPM Web site has over 450,000 visits per year. During the winter months, the IPM group is busy with educational programs and meetings that supply general information on IPM, as well as updating the fruit and vegetable manuals that are available through UConn. The UConn IPM Web site is www.hort.uconn.edu/ipm.
Both Los and Boucher note there are many fruit and vegetable growers in Connecticut who are becoming increasingly aware of the value of IPM as a means of doing a better, safer, more eco-sensible job of farming. UConn’s IPM programs have been shown to be a valuable tool in the growing movement to reduce the use of synthetic pesticides in the production of our food.
The author works for Central Connecticut Farmer’s Cooperative in Manchester, Conn.