Building a Safe Pesticides Industry with Bioproducts and Biomethods
Three publications on my desk are the motivating factors behind this issue’s Compost Users Forum. The first is our own Compost Science & Utilization (Summer, l999), a journal that reports research throughout the world dealing with the process and product of compost making. The initial report in this issue is titled: “Prospects for Composts and Biocontrol Agents as Substitutes for Methyl Bromide in Biological Control of Plant Diseases.” The increasing recognition of the role of compost in pest management has great implications for producers of quality compost. It reflects the transitions that have so drastically changed perceptions of how feedstocks (wastes) impact food production and environmental quality.
The second publication is Alternative Agriculture News (September, 1999), a bulletin from the Henry Wallace Institute for Alternative Agriculture. Its front page news item provides data on an EPA decision to eliminate and reduce uses of two pesticides. Rounding out my collection is an “Issue Brief” from the World Wildlife Fund with the headline: “Successful, Safe, and Sustainable Alternatives to Persistent Organic Pollutants.”
Let’s begin with the World Wildlife Fund, since it sets forth why we need alternative solutions for pest management. The following is excerpted from the bulletin.
Over the past 75 years, modern civilization has developed synthetic chemicals to control disease to combat insect pests. In the course of this Chemical Revolution, human societies around the world have released vast quantities of man-made compounds, only to discover later that some of these miracle chemicals posed unanticipated hazards. Today, there is unequivocal evidence that a number of widely distributed man-made chemicals have already done serious damage to the health of wildlife and people and continue to pose an ongoing danger.
As evidence has mounted about contamination from synthetic chemicals, the unique dangers posed by one group of chemicals called persistent organic pollutants (POPs) have become a pressing concern. These carbon-based compounds or mixtures pose a particular hazard because of four characteristics of their chemistry: they are toxic; they resist the normal processes that break contaminants in the body and the environment; they are not readily excreted and accumulate in body fat; and they can evaporate and travel great distances.
As farmers, public health officials, and pest control applicators have sought to replace POP pesticides, they have frequently looked to other synthetic chemicals that do not persist, accumulate in fat, or concentrate in the food web. Although such substitutions might seem to be the quickest and easiest alternative, these compounds have proved equally dangerous in their own ways. Many of the pesticides used today, such as organophosphate and carbamate insecticides, are much more acutely toxic to people, wildlife, aquatic organisms and beneficial insects than the older persistent pesticides they replaced.
The time has come to accept that there are no simple, universal prescriptions for pest problems and to turn to solutions appropriate for the site, the agricultural system, and the local culture and economy. Alternatives will, however, be viable only to the extent that they address the difficulties of making a transition from a chemically to a biologically based system for managing pests.
Approaches known as Integrated Pest Management (IPM) in agriculture and Integrated Vector Management (IVM) in public health offer such flexible, sustainable solutions. IPM uses a diverse mix of approaches to control pests, ranging from cultural to chemical controls.
TWO PESTICIDES CALLED “OUT” BY EPA
Sustainable farming practices have been consistently emphasized by the staff and directors of the Henry Wallace Institute for Alternative Agriculture. Those practices cover soil and pest management, as well as on-farm organic residuals management. A report in its latest issue of Alternative Agriculture News cited this information under the headline “EPA Eliminates and Reduces Uses of Two Pesticides.”
The EPA last month announced plans to eliminate specific uses of methyl parathion, and eliminate some uses of and significantly lower allowable residues for azinphos methyl, two organophosphate pesticides. It also announced an 18-month schedule for completing its review of all 39 organophosphates. Under the Food Quality Protection Act, the EPA said it would next year eliminate the continued use of methyl parathion on apples, peaches, pears, grapes, nectarines, cherries, plums, carrots, certain peas, certain beans, turnips, and tomatoes. Approximately 4.2 million pounds of the pesticide were applied last year, but 75 percent of that was applied to cotton, corn, and wheat, which are not affected by the new regulations. The EPA will reduce application rates and required practices for azinphos methyl that will result in the significant reduction of allowable residues on apples, pears, and peaches. It will be banned on sugar cane and on cotton east of the Mississippi River.
USDA Deputy Secretary Richard Rominger participated in the EPA briefing about the regulatory actions. “It’s clear that agriculture must do more than react chemical by chemical, waiting until cumulative pesticide risks are calculated,” he said. “To respond to this challenge, the department is working commodity by commodity and region by region to develop the best strategies for moving toward pest management practices that have the least risk.”
Many organophosphates were used as a replacement for DDT after its ban in 1972. According to The Washington Post (August 3, 1999), “Because of questions about organophosphates’ possible toxicity to humans, particularly to the developing nervous systems of infants and children, critics have for years been calling for tougher restrictions or outright bans on the use of the pesticides.”
PROSPECTS BRIGHTEN FOR COMPOSTS AND BIOCONTROL PRODUCTS IN COMMERCIAL AGRICULTURE
Methyl bromide one of the most widely used soil pesticides that has been applied on a yearly basis on some crops is scheduled to be phased out by 2005 because of its negative impacts on the environment. “Composts have long been recognized to provide a degree of control of diseases caused by soilborne plant pathogens,” write researchers Tom J.J. DeCeuster and Harry A.J. Hoitink in their Compost Science & Utilization paper. Until the 1930s, they explain, organic amendments consisting of animal and green manures coupled with crop rotation were the principal control methods. As recognized dangers from the kinds of pesticides described above lead officials to ban their use, once again we can see modernized versions of those integrated methods becoming widespread.
In the summary of their paper, DeCeuster and Hoitink provide this vision of what we can expect when alternative solutions shift into mainstream application:
“The loss of methyl bromide (MB) and our increased awareness of environmental problems caused by inadequate solid waste utilization practices promise to provide a boost to the utilization of organic amendments in agriculture. This in turn will reduce the potential for soilborne plant pathogens to cause epidemics that cause major losses because such amendments generally decrease the ability of plant pathogens to cause disease. In many applications, however, suitable alternatives to MB have yet to be developed. Especially in intensive horticultural systems where continuous cropping is practiced, MB will be difficult to replace. No single alternative management technique is likely to replace MB in all its applications. Rather, groups of alternatives, integrated within various combinations of biocontrol treatments depending on the needs of the grower, will be required to replace MB. This approach to integrated pest management will also require careful monitoring for pest problems. Factors such as climate, soil type and structure, time of year, the quality of the organic amendment, and crop will need to be considered. While this may prove to be inconvenient in the short run, over the long term it will lead to more sustainable agricultural practices while improving the environment on, as well as off, the farm. The nursery industry in many parts of the world already has taken advantage of these ideas by using disease suppressive composts. The same is occurring in other crops, including strawberries, as farmers become more aware of soil organic matter quality issues.