P ENNSYLVANIA Mushroom Integrated Pest Management H andbook The PA IPM Program is a collaboration between the Pennsylvania Department of Agriculture and The Pennsylvania State University College of Agricultural aimed at promoting Sciences Integrated Pest Management in both agricultural and nonagricultural settings. This publication was developed by the PA IPM program with the cooperation of the American Mushroom Institute. Table of Contents Introduction 4 I. Theory of Integrated Pest II. Integrated Pest Manage- P. Coles Management 5 ment in Mushroom Production 20 A. History, Definitions, and the Economic Threshold 6 A. Specific Control Techniques S. Fleischer 1. Exclusion 21 B. Pesticides and Resistance in P. Coles IPM 13 S. Fleischer 2. Cultural Control 27 P. Coles/W. Barber 3. Biological Control 33 D. Rinker 4. Chemical Control 37 P. Coles B. Pesticide Safety 43 S. Whitney C. Pest Species Biology and Control 1. Arthropod Pests 47 C. Keil 2. Fungal Pathogens 52 P. Coles/W. Barber 3. Weed and Indicator Molds 61 D. Beyer 4. Bacterial Diseases 75 P. Wuest 5. Nematodes 78 P. Coles 6. Virus Disease 85 P. Romaine Introduction In this handbook we have addressed the Mushroom growing lends itself natu- Other features of mushroom production most important pest organisms with the rally to IPM. It is one of the few forms make IPM a necessity, not an option. potential to reduce mushroom yield and of agriculture in which the crop is With production measured in pounds quality. The handbook is intended for grown inside climate-controlled per square foot rather than in bushels or growers, as well as researchers, as both buildings. This offers two advantages tons per acre, mushroom growing is an educational tool and a reference not available to most other crops. First, very dense farming. If a pest gets into a manual. Recommendations presented control of the internal environment of room, it can spread rapidly because of here are not intended to bind growers in the growing room provides an impor- the large amount of food available their decision-making processes. Rather, tant weapon against many pests. within a relatively small space. In they should serve as a guide for develop- Temperature and humidity manipula- addition, many pests cannot be con- ing effective Integrated Pest Manage- tions, for instance, are two of many trolled using chemical pesticides, either ment (IPM) programs. Each grower cultural options available in mushroom because there are no products labeled should develop specific operating pest control with IPM. Second, since for mushroom use, or because materials procedures and checklists specifically the crop is grown indoors, pests can be don’t even exist for a specific type of tailored for individual use. In addition, excluded. This control measure is pest organism. Increased regulations are as technology is always changing, this unavailable to farmers of field crops, driving up the cost of producing new handbook will be updated periodically. who have little control over pest pesticides, making it difficult or invasion. An effective IPM program impossible for chemical manufacturers The handbook is divided into two parts, takes advantage of these particular to invest in a minor-use crop like covering the theory of IPM and the characteristics of mushroom growing. mushrooms. Usually, we are forced to practical aspects of IPM in mushroom rely on pesticides developed for other growing. The theory section defines commodities. An IPM program that IPM and gives it historical perspective. excludes pests and takes advantage of It also explains the concepts of pest the ability to manipulate the growing management and types of control, and environment not only is a more effective the importance of understanding pest means of pest control but also allows life cycles and biology. The section on limited dependency on chemical IPM in mushroom growing describes pesticides. how unique features of mushroom crops can be used effectively in IPM, and how These features make the IPM approach the theory of IPM can be applied the most effective and economical effectively. means of long-term sustainable pest control. Anyone trying to control pests without IPM eventually will end up at the mercy of those arthropods and mushroom diseases. We hope this manual will help you avoid that fate. 4 I. Theory of Integrated Pest Management 5 A. History, Definitions, and the Economic Threshold Shelby J. Fleischer These efforts at supervised control Integrated pest manage- History, Definitions, and declined rapidly when DDT and other the Economic Threshold new insecticides came into use. By the ment is the [information- late 1940s, over 90 percent of acreage Vernon M. Stern was working for the was treated with new materials, calcium based] selection, integra- Westside Alfalfa Pest Control Associa- arsenate fell into disuse, and the Pest tion in the San Joaquin Valley, Califor- Control Associations disappeared. The tion, and implementation of nia, a big association of growers new materials worked well for less cost, involving 10,285 acres when it formed so Vernon M. Stern went to graduate pest control based on in 1945. The association was organized school with Ken Hagen, the first person to help decide when to apply insecti- in charge of the Westside Association, and Robert van den Bosch, who had predicted economic, eco- cides against the alfalfa butterfly. also been in charge of the Association The alfalfa butterfly was not the most for a period of time. They worked with logical and sociological serious pest in alfalfa, but at times it Professor Ray F. Smith, who had flared up and caused very serious loss. initially organized the Pest Control consequences. Alfalfa growers had materials like Associations. calcium arsenate at their disposal, and they used these materials frequently, but It was not long before another insect, at significant expense and with hard the spotted alfalfa aphid, came into the Bottrell, 1979. work. The growers formed an associa- San Joaquin Valley, and by 1955 this tion after entomologists showed that a aphid was resistant to pesticides. Smith and his students (Stern, van den Bosch, Council of Environmental parasitoid controlled the butterfly most of the time, and that growers could and Hagen) imported an exotic parasi- Quality make many fewer pesticide applications toid and studied native predatory if they could estimate how well the insects. Both the parasitoid and the parasitoid was controlling the butterfly predators were effective when not larvae early in the crop growth cycle. destroyed by pesticides. They then The association hired people to do the found insecticide materials and use fieldwork and calculations and to give patterns that were relatively selective, advice. The Westside Alfalfa Pest allowing the natural enemies to coexist Control Association called this “super- with the valuable insecticide tools. vised control.” The system was success- ful, and soon the Westley Pest Control Association and the Tracey Pest Control Association formed in other parts of California. 6 In 1959 Vernon M. Stern with his co- The concept of economic injury level is This “Integrated Control” concept, authors Smith, van den Bosch, and shown in Figure 1. (Similar figures can published in 1959, was quickly ex- Hagen, wrote a paper entitled “The be found in Stern’s paper, published panded to include all methods of Integrated Control Concept,” (Stern et about 40 years ago, and similar concepts control. Thus, the Integrated Pest al. 1959) in which they generalized were in use in cotton production almost Management concept was born at least about integrating biological controls 75 years ago.) The figure shows that the 40 years ago. The concept was not born and insecticides. To make this work, pest density is changing over time. At solely in California; similar develop- they discussed monitoring, which low densities, the costs of the damage ments were occurring in Arkansas for requires understanding of sampling and done by the pests are less than the costs cotton crops and in Canada for apples. measurement of pest density. They of control, so it does not pay for the The concept arose from a philosophy noted how pest populations fluctuate manager to add the control. At higher for which the objective is to manage a over time. By monitoring density, they densities, however, it does pay to pest population below economically argued, intervention with pesticides can control. Pest density is dynamic, and damaging levels, and in a way that is be limited. This practice limits chemical managers can make short-term predic- practical for growers, by integrating applications to those necessary times tions about what the density soon will multiple control options (see Perkins and places where other tactics are not become. Managers usually want or need 1982 for a full historical perspective). sufficient. to implement controls a short time IPM always has emphasized integration before the Economic Injury Level is of control tactics, including pesticides, So when does it become necessary to reached. The Economic Threshold is the and monitoring to help determine time intervene with pesticides? In many density at which controls are added. It is and location for pesticide application. respects, this is an economic decision. It set so that, if controls are applied and requires relating economics or commer- are effective, the Economic Injury Level cial goals of production to fluctuating is not reached. pest density. Simply defined, the time to intervene with a pesticide is when the Figure 1. Graph of economic injury level. expected gain from using the pesticide equals the costs associated with its use. Pays to Control The pest density at which the gain equals the cost is the Economic Injury Level. Thus, IPM relates pest popula- tion dynamics to commercial produc- Pest Population tion goals. Economic Injury Level Does Not Pay to Control Time 7 Today, there are many definitions of Integrated Pest Management.