DOCUMENT RESUME SO 027 928 ED 416 143 Welch, Mary A., Ed. AUTHOR The Cost of Keeping Up Appearances. TITLE Purdue Univ., West Lafayette, IN. School of Agriculture. INSTITUTION 1996-00-00 PUB DATE 23p.; For other booklets in this series, see SO 027 918-929. NOTE Some colored pages and graphs may not reproduce well. School of Agriculture, Office of Academic Programs, Purdue AVAILABLE FROM University, 1140 Agricultural Administration Building, West Lafayette, IN 47907-1140. Non-Classroom -- Guides Collected Works - Serials (022) PUB TYPE (055) Economic Issues for Food, Agriculture, and Natural JOURNAL CIT Resources; n11 Spr-Sum 1996 MF01/PC01 Plus Postage. EDRS PRICE *Agriculture; Conservation (Environment); *Economics; DESCRIPTORS Environment; Environmental Education; Food; Landscaping; *Natural Resources; *Ornamental Horticulture; Secondary Education; Social Studies; *Technology ABSTRACT This issue focuses on the costs of keeping up appearances by landscaping the environment. Although insects can be a threat to plant health, much of the injury they cause will only threaten plant appearance. The study comes from a survey of two groups, landscape specialists and homeowners, who were asked to identify which plants in a photograph series they would consider damaged and which they would want their landscape shrub, commonly management company to treat. Six photographs of a widely-used known as a burning bush, were prepared with varying discoloration and damage ranging from uninjured to half stippled white. The survey revealed that landscape specialists have the same general tolerance for plant injuries as their clientele. The possible value and application of this research to commercial business is explored, along with a description of a model of the integrated pest management (IPM) plan. The decision making model for use of the IPM is explained. A student quiz concludes the booklet. (EH) ******************************************************************************** * Reproductions supplied by EDRS are the best that can be made * * from the original document. * ******************************************************************************** I 1 U S DEPARTMENT OF EDUCATION Office of Educational Researcn and Improvement EDUCATIONAL RESOURCES INFORMATION CENTER (ERIC) F., This document has been reproduced as received from the person or organization Originating it Minor changes have been made to Improve reproduction quality Points of view or opinions slated in this document do not necessarily represent official OERI position or policy PERMISSION TO REPRODUCE AND DISSEMINATE THIS MATERIAL HAS BEEN G ANTED BY TO THE EDUCATIONAL RESOURCES INFORMATION CENTER (ERIC) LE AVM BEST COPY About the cover: Dr. Cliff Sadof.evaluating a pest problem. ECONOMIC ISSUES for Food, Agriculture arrd Natural Resources is published by the Office-of Academic Programs, Mary A. Welch, editbr. Spring / Summer 1996, No. 11 is The lost of Keeping Up Appearances A LESSON IN DECISION MAKING..... GroWing plants for beautifying the landScape is big business. As a customer searches for the "greenest," "reddest," or "plumpest" produce in the supermarket, gardeners are seeking healthy-looking plants in a garden center to beautify their yards. Given a choice, most customers will purchase. the fullest,Stfongest and healthiest-looking plants. Although insects can be a threat to plant health, much of the injury they cause will only threaten plant appearance. Garden center owners and nursery plant producers need to know the amount of cosmetic injury that is acceptable to potential customers so they can set the objectives for their pest management programs. The presence of insects and disease'on a plant can affect purchase decisions because of the detection of pests themselves or their effects on plant appearance. Consumers are not likely to purchase plants crawling with pests because of their inherent fear of insects and disease. More astute gardeners may also be thinking about how introductions of these 'pests to their yards may call for future pesticide use. Increased aversion to pesticides will cause many customers to demand pest-free Plants. Pest-induced changes in plant- appearance (e.g., defoliation) affect the decision to purchase a plant in ways that are much different from the presence of the-pest itself. Consumer perception of plant appearance is subjective and based on personal tastes. Because garden centers can readily remove conspicuous insects,- managers are interested in knowing how changes in plant appearance alone affect their purchasing decisions. Clifford Sadof, professor in the Department of Entomology at Purdue University, has 3 4 studied changes in plant appearance caused by pests. Sadof is interested in how much plant" injury landscapers and gardeners are willing to tolerate. The results of his work c\,ould be used to help growers Set management targets while allowing them to use the minimum amount of pesticides. Injury = leaf disfigurement or destruction MOTE: Damage = economic loss To study this question, Sadof and a graduate student, Curt Alexander, prepared a series of six photographs of a widely-Used shrub, commonly known as 'a burning bush. This-ornamental plant N often used in landscaping._ During long, hot dry months_itcari become infested with spider mites. The spider mites pierce the Surface of the leaf and suck up the juicethat bubbles from the puncture. This injures, the leaf and causes'the pierced area to become stippled with white flecks. ; When infesfations are.high and go untreated,- significant portions of the plant become discolored. This may be the first time some casual observers notice the injury. A .. clOser look will show hOW individual leaves have been discolored. Any number of potential customers are likely.to disagree on the amount of discoloration that makes'a plant unattractive. They each have their own concept of.what an attractive plant looks like. The photographs.prepared by Sadof and Alexander represented drangeOf discoloration from uninjured to half stippled. white. This was based on the average discoloration of a randoM sample of 25 leaves taken from each plant. AS it was important for people to react to the discoloration of the leaves, not the Obvious presence of mites, webs, an indication of the most serious 'damage, were not visible in any of the, - photographs. Two groups (landscape specialists and homeowners) were asked to identify the plants in the photographs they considereddamaged, as ,well as those they would want their landscape management company to treat. The photo- graphs represented discoloration of each plant on a scale of 1 - 6 with 1 representing no discoloration and 6 being half discolored. ' RESULTS This survey revealed that landscape specialists have the same general tolerance for plant injuries as their clientele. More than half the respondents from both the providers and recipients of landscape management services considered a plant with a discoloration ranking of 3.4 to be damaged. This represents approximately 5-10 percent leaf discoloration as seen in Figures 1 and 2. Wanting to Treat Plant 100 80 Figure 1 60 E 13 client industry 40 1:1 20 41 o. 2.4 3.4 3.8 1.4 2.6 1 Average Discoloration Rank Recognition of Plant Damage Figure 2 client 40 industry 2 6 2 4 3.4 3.8 1.4 1 Average Discoloration Rank 5 Also, the same level of injury caused landscapers and clients to want a plant to be treated. Interestingly, there was quite a bit Of variation in the responses of people to pest injury. About ten perCent of the respondents wanted the uninjured plant to be treated even though fewer than five percent of them viewed the' plant as damaged. At the other end of the spectrum, about ten percent of the clients and landscapers did not want a plant to be. treated even though all respondents thought the plant was damaged. Sadof's impression of thiS difference is that clients and landscapers at either extreme are responding to their views about using pesticides and -not looking closely at the conditions of the plant. Sadof suggests that landscapers recognize the diversity of opinion among their clients and meet With them to set acceptable goals. What Value and Application Would This Have to a Commercial Business? As the public becoMes more and'more -sensitive to environmental issues of safe water and food, more producers of plant materials, are looking"for ways to reduce the amount of . pesticides they. use. Integrated pest management (IPM) is such a plan. It restricts .TestiCide applications to occasions when the number of pests, present threatens the value-of the crop.. 'In the past, Many growers used a "spray by the calendar" routine. Whether or not insects were present, spraying wa's done.tO ensure that pe'sts did not attack valuable, cash crops. The purpose-of an1PM,program is to minimiie damage of a saleable product so .that it is acceptable to the potential customer. For example, on crops.such as melons or cucumbers without an IPM program, a grower may spray 10 to 12 times a season at a cost of .$100-120 per acre. An IPM program may reduce the cost to $50-60 per acre by cutting the number of sprays in half. The savings on one spray can pay for the program. Participants of IPM programs have behind- the-scenes support, with the likes of Sadof. Sadof meets regularly with participants of his IPM program to help them learn more about the insects that affect their plants and how to control them. By participating in Sadof's trainings, nursery managers can eventually become local experts. This knowledge can add value to their businesses, as growers look to them for advice on when to apply pesticides. How Does an IPM Decision Model Work and How Is It Calculated? To Spray or Not to Spray How are decisions made about applying pest controls to ornamental plants? Remember to consider what we know about the attitude of customers and whether we are working with professionals, owners or potential owners of landscape plants. The Classic Decision-Making Model may be used by a producer of a crop such as soybeans which is valued for its weight or bulk. The model is referred to as an EIL ; (economic injury level) where EIL = C/VID EIL = number of injury equivalents per production unit (e.g., insects per acre, all of which live to attain their full injury potential),C = cost of the management activity per unit of production (e.g., $ per acre), V = market value (utility per unit of . production (e.g. $ per pound or bushels), I - injury units per insect per production unit (e.g., proportion defoliated / insect per acre)], and D = damage per unit injury e.g., (pounds or bushel reduction per acre) / proportion defoliated). This type of model can be used 7 8 because the producer can measure the results by weighing the crop. The producer has no economic stake in the beauty.of the plant, just in its yield. Pest management actions dre taken to prevent insects from exceeding the EIL density. The ElLis USING BREAK-EVEN POINT TO MAKE A DECISION: simply a decision-making tool to determine the break-even point in a management situation, This is the point where the cost of taking an action is balanced against the loss resulting from not taking an action. The cost of For example, consider the following situation: applying a pesticide is $10 per acre. This gives- C a value of $10. When the expected market value of the crop harvested from one acre. is $1000, V = 100.0.. If an average insect can consume 0.01 percent of the leaves, I = 0.0001. Finally if each percent of leaves lost reduces yield by 1%, D = 0.0. The denominator of the equation (VID) represents the potential gain from controlling each insect. In this case it is $1000 X 0.0001 bulk volume X .01 unit of volOme lost per insect, or $0.001 lost per insect (one tenth of a cent per bug). The EIL is simply the number of insects it takes to equal the cost of applying a control to an acre of plants, C ($10), is 10,000 insects per acre. In reality, a soybean farmer has little idea how much of the crop will be worth at harvest. He or she is also unsure about the weather and how it will influence the volume of crop yield; or the ability of pests to increase their numbers. Much of agricultural research involves developing techniques to help farmers make an educated guess based on the potential yield, price, and pest abundance. In contrast to a soybean grOwer, Crops produced by the nursery industry are.valited for objective qualities such as size and number, as well as subjective qualities like plant appearance: Nursery managers use a decision; making Model that is.referred to as a Hybrid . Model EIL because it combines'subjective and objective 'measures of crop quality. EIL = C/VIDK where C = the cost of control (e.g. dollars per plant), V = economic value"of undamaged goOd ($ per plant),.I a proportion of injury per unit of pest density (discoloration or .9 defoliation, pest per plant), D = proportion of consumers perceiving damage per unit of pest injury ($ lost in sales per unit of injury per plant), \ancl-K .= effectiv-eness of control., The key difference using the hybrid model is that the aesthetic qualitylof the plant is the primary consideration when calculating the value (V) and damage (D) coefficients for plants of a given size. e 'In laridscapes, neither the classic or the hybrid model is appropriate for evaluation. Here, a third model called an aesthetic injury model is used because it only takes into account the level of injury that is acceptable to a consumer. The photographic survey of burning bush`injury determined that most homeowners and landscapers wanted a control measure'to be taken when only 10 percent of the leaves were discolored. As the damage approaches this 10 percent threshold, groundskeepers are told by their clients to JUST DO IT!! In 1991, Sadof implemented au IPM program on Purdue University's campus that reduced pesticide use on campus trees and shrubs by more than 50 percent. It changed Purdue's landscape management philosophy frOm one of pest prevention to one of problem prevention. Sadof used his 10 percent threshold to develop a rule- of thumb for maintance personnel. involved in the IPM program. He also.developed and tested Purdue Landscape IPM software, now available to the public, which manages plant inspection records and generates reports designed to facilitate management efforts and comply with EPA requirements for pesticide record keeping. Prior to IPM, pesticides were applied to plants odthe Purdue campus at specific times of the year as part of a pest-prevention, program. Now pesticides are used only in areas where pests have been detected and assessed as a threat. As a result of IPM, the