• Topics: Food and Resource Economics | Nursery Pest Management | Commercial (Greenhouse and Nurseries) Pests | Pesticide Applications and Equipment | Plant Growth Regulators | Commercial (Greenhouse and Nurseries) | Hodges, Alan Wade | Aerts, Michael J

Pest Management Practices and Chemical Use in Florida's Ornamental Plant Nursery Industry ¹

Abstract

A survey of ornamental plant nursery firms in Florida was conducted to document pest management practices and chemical use in 1995. Wholesale ornamental nurseries in 16 Florida counties were randomly selected for the survey, which was administered through personal interviews by University of Florida County Extension faculty and assistants. A total of 221 firms were surveyed. These firms had annual sales of $138 million, 3,503 acres of production area, and 3,460 employees. Survey respondents used greenhouse, open container, and field production systems, and had crops including foliage, trees, woody ornamentals, bedding plants, flowers, liners, and other crops. The majority of growers reported that costs for pest management, including materials, labor, and equipment, represented less than 5 percent of direct costs of production. Insecticides were reported used by 98 percent of respondents, fungicides by 90 percent, herbicides by 88 percent, growth regulators by 47 percent and soil fumigants by 4 percent. Respondent firms used an average of 5.8 different insecticides, 2.1 herbicides, 4.2 fungicides and 1.0 growth regulators. The most commonly used pesticides were the fungicides metalaxyl (Subdue), copper, mancozeb and chlorothalonil (Bravo, Daconil), the herbicides glyphosate (Roundup) and oxadiazon (Ronstar), and the insecticides acephate (Orthene), diazinon and avermectin (Avid). Most respondents considered pest management and scouting to be the responsibility of the owner(s) rather than employee managers, growers or other specialist. Two-thirds of firms reported scouting for pests more than once a week, but less than half of firms followed a schedule for deliberate scouting on a regular basis. The incidence of 30 specific integrated pest management (IPM) practices followed ranged from 3 to 83 percent. Fifteen percent of respondents reported using biological control agents, primarily against mites and whiteflies on palms and other foliage plants.

Acknowledgements

Support for this survey project and publication was provided by the National Agricultural Pesticide Impact Assessment Program (NAPIAP) of the U.S. Department of Agriculture. Norman Nesheim is the state liason representative for this program. University of Florida/IFAS county faculty who conducted survey interviews with growers were Gary Brinen, Gerri Cashion, Michael Demaree, David DeVoll, Terry Delvalle, David Dinkins, Patricia Grace, Liz Felter, DeArmand Hull, Linda Landrum, Cathy Neal, Bill Schall, Roger Newton, Dan Schrader, Bob Whitty, and Andy Rose. Howard Bardsley conducted numerous interviews in Dade County as a temporary contractor. Ken Portier and Jean Stewart of the UF/IFAS Statistics Department performed statistical analysis of the data.

Introduction

The Florida Nursery Industry

The ornamental nursery industry in Florida is the second largest in the United States, with 5061 farms, annual revenues exceeding $1 billion, production area of 35 thousand acres in the open and 147 million square feet under greenhouse or shadehouses (U.S. Dept. Commerce, 1993). The industry in Florida has significant production of woody ornamentals, tropical foliage, and flowering plant products (Hodges and Haydu, 1996).

The humid, sub-tropical environment in Florida is ideal for plant production, but is also highly conducive to many pest organisms. Some pests are endemic to nursery sites and are active year round in Florida. This ornamental nursery industry intensively manages pests because a low threshold for economic damage is dictated by the consumer's demand for cosmetically unblemished plants. However, the use of pesticides for control of pests represents not only a significant economic cost to nursery producers, but also may harm non-target organisms in the agro-ecosystem and may pose a risk to health and safety of nursery workers and neighboring communities.

Project Objectives

This survey project was undertaken to document pest management practices and chemical use in Florida's commercial ornamental nursery industry, as part of the educational efforts of the University of Florida/IFAS. This project was organized under State Major Program FL112, which seeks to serve the needs of commercial ornamental plant growers for information on pest management. This survey was conducted in 1996 and concerned activities of respondents in 1995. A followup survey is planned in approximately 5 years to measure changes taking place in the industry and to assess the impacts of UF/IFAS programs during the intervening period.

Survey Methods

Questionnaire Development

The survey instrument was developed according to methods described by Salant and Dillman (1994) and in consultation with UF/IFAS faculty, and was pretested with several firms to assure that questions were clear to respondents and were answerable. Information requested by the questionnaire was as follows:

1. Production areas used in 1995, by type of crop and type of production systems used (acres or square feet). Production systems specifically covered included greenhouse/shadehouse systems, open growing areas for containerized plants, and open growing areas for field grown plants. Specific types of crops included tropical foliage plants, trees, woody ornamental shrubs, bedding plants, floriculture crops, liners, and others.

2. Use of specific chemical products, including insecticides, herbicides, fungicides, growth regulators, and soil fumigants, by specific formulation. Some 88 individual chemical active ingredients were identified as being labeled for nursery use. In the case of insecticides and fungicides, information was also requested on the types of insects or diseases targeted. Respondents were asked to indicate simply whether or not each chemical was used in 1995; it was not feasible to quantify the level of use in terms of number of applications or area treated.

3. Types of pest scouting, frequency conducted, and person responsible.

4. Application of pest control treatments according to a predetermined schedule or only when pests are detected, or both, for each of the four classes of pests: insects, nematodes, weeds, diseases.

5. Use of 10 possible considerations for deciding whether to administer a pest control treatment: pest population level, pest population changing, degree of pest damage, pest life stage, presence of predators/parasites, plant disease inoculum level, weather, treatment cost, projected marketing date, labor availability.

6. Use of Integrated Pest Management (IPM) practices, selected from a list of 30 possible practices.

7. Use of biological control agents, including type(s) of organism(s) used, pest(s) targeted, crop(s) treated, and the average area treated.

8. The importance of seven issues for pest management: improving control of pests, increasing ability to work in the nursery, increasing salable plants, lowering environmental impact, lowering cost of production, reducing potential pesticide resistance, reducing use of pesticides.

9. Disposal practices for empty pesticide containers.

10. Expenses for pest control, including labor, materials and equipment as a percentage of total direct costs.

11. Hourly wages for employees involved in pest control activities.

12. The number of full time equivalent employees working for the company and the number involved specifically in pest management activities.

13. Nursery product sales of the company in 1995, either actual sales, or the appropriate category representing a range of figures.

Survey Sampling Design

The population of ornamental horticulture firms for this survey was taken from the Florida Department of Agriculture and Consumer Services, Division of Plant Industry (FDACS-DPI) certified nursery directory, listing a total of 7268 firms for 1995. Some 4300 firms having wholesale business in ornamental or native plant products were considered eligible for the survey pool. Firms were excluded which had only retail business or grew only non-ornamental plants (e.g. citrus). In order to measure effects of location or business size on pest management practices and chemical use, firms in the survey pool were stratified into 3 size classes based upon plant inventory, and three regions of the state, North, Central, and South, corresponding to USDA plant hardiness zones 9a, 9b, and 10. The firm size classification was based upon the most recent DPI inventory data available for each firm.Sample numbers required for this survey were calculated to achieve a target precision of plus or minus 10 percent in estimating the true mean of continuous variables (e.g. acreage) at a statistical confidence level of 90 percent. A target sample size of 262 firms was calculated to meet these parameters, based on an estimated coefficient of variation of 0.30 for continuous variables. This number represented about 6 percent of the population of eligible firms. The required sample numbers were allocated to each survey stratum, by firm size and geographic region, as shown in Table 1.

Nursery firms were surveyed in 18 Florida counties, including Highlands, Lake, Orange, Hillsborough, Pasco, Manatee, Citrus, Seminole, Volusia, Sumter, Brevard, Alachua, Bradford, Duval, Putnam, Martin, Dade, and Broward (Figure 1). The required sample numbers were distributed among these counties in proportion to their share of the total population of firms within each region. For each county, a list of firms was randomly generated for the survey, by firm size class (large, medium, small). These lists contained twice as many firms as required for the final sample, in order to allow for replacement of non-responding firms.

Figure 1. 

Survey Implementation

Introductory letters were mailed to firms selected for the survey to describe the nature of the survey. Interviewers called upon selected firms in advance to obtain consent from the company owner or Chief Executive officer, and to arrange an appointment to conduct the interview with a designated company representative who is "most knowledgeable about the company's pest management practices" . Every effort was made to contact the randomly selected firms in order to minimize bias in the survey. In cases where it was not possible to contact the firm, or the owner or manager chose not to participate in the survey, a replacement firm was selected from the list of alternates.

Because of the large amount of information to be collected and the confidential nature of some information, questionnaires were administered by personal interviews with company representatives. In most cases, UF/IFAS agents conducted the interviews. Enumerators were hired to assist with the survey in 3 counties (Dade, Hillsborough, Putnam). Interviews were conducted by asking each question and recording the respondent's answer on the survey form. Enumerators were given detailed explanations for each specific question, and were instructed to develop a standardized presentation or manner of asking the questions. Completed questionnaires were returned to the project leaders for data checking, entry and analysis.

Survey Results

Usable survey questionnaires were completed by 221 respondent firms. Counties in the North, Central, and South Florida regions represented 12, 39, and 49 percent of sampled firms, respectively. Dade, Hillsborough, Broward, and Orange counties each contributed at least 24 respondents to the survey. The numbers of firms surveyed in each county are given in Appendix Table A1.

Chemical Use

Survey respondents were queried about their use of 32 insecticides, 24 herbicides, 18 fungicides, 11 growth regulators and 3 soil fumigants that are labeled for use on ornamental crops. In most cases, information was collected on specific formulations of chemicals. Results for the number and percentage of firms using each chemical are presented below in Tables 3-7: insecticides used are summarized in Table 3, herbicides in Table 4, fungicides in Table 5, growth regulators in Table 6, and a summary by chemical class, production system and crop in Table 7.

Insecticides were used against pests including aphids, borers, caterpillars, leafminers, mites, nematodes, scales, thrips and whiteflies (Table 2). Mites, aphids, and whiteflies were the most important pests targeted, representing 18, 17 and 16 percent of total insecticide uses, respectively (Table 2).

At least one of the 32 insecticides listed in the questionnaire was used by nearly all (98%) of firms surveyed, and this result did not differ significantly across regions, crop specialties, production systems or firm size classes. The most commonly used insecticides were acephate (Orthene), diazinon, and avermectin (Avid), which were used by 59, 43 and 43 percent of firms, respectively (Table 3). Reduced risk insecticides, such as Bacillus thuringiensis , insecticidal soaps and horticultural oils, were used by 32, 30 and 29 percent of nurseries, respectively. On average, 5.8 different insecticides were used by an individual firm, more than any other class of pesticides (Table 7). The number of different insecticides used by individual firms was higher in South Florida (6.4) than in other regions, for bedding plants (8.6) and floriculture crops (7.1), and for larger firms (11.9).

Herbicides were classified as pre-emergent or post-emergent types. At least one herbicide was used by 88 percent of survey respondents, however, in the northern part of Florida a somewhat lower percentage of firms (74%) used any herbicides. The most commonly used pre-emergent herbicides were oxadiazon (Ronstar), oryzalin (Surflan), oxyfluorfen plus pendimethalin (OHII), isoxaben plus trifluralin (Snapshot TG), and oxyflourfen plus oryzalin (Rout), used by 25, 15, 13, 11 and 9 percent of firms, respectively (Table 4). Glyphosate (Roundup, Expedite), a post-emergent, non-selective herbicide was the most commonly used of all chemicals, used by 82 percent of growers. On average, 2.1 different herbicides were used by an individual firm (Table 7).

Fungicides were widely used to combat plant diseases in Florida's nursery industry, due to the very hot and humid conditions which are favorable for fungal organisms. Some type of fungicide was reported used by 90 percent of firms. The most commonly used fungicides were metalaxl (Subdue), copper (Kocide), mancozeb (Dithane), chlorothalonil (Bravo, Daconil), fosetyl aluminum (Aliette), etridiazole plus thiophanate methyl (Banrot), iprodione (Chipco 26019), and thiophanate methyl (Cleary 3336, Domain, SysTec 1998), which were used by 34 to 57 percent of growers, respectively (Table 5). On average, 4.2 different fungicides were used by the typical firm (Table 7). A somewhat higher number of fungicides were used by firms with greenhouse production systems and for growing bedding plants, while fewer fungicides were used for field production systems for trees and woody ornamentals.

Growth regulators were used in the nursery industry generally less than for the preceeding three classes of chemicals. At least one growth regulator was used by 47 percent of surveyed firms. The most commonly used growth regulators were daminozide (B-Nine), IBA (Hormodin) and paclobutrazol (Bonzi), used by 17 to 13 percent of firms (Table 6). IBA is used as a rooting hormone while daminozide and paclobutrazol are used to control plant size and form, primarily for floriculture crops. Typically, an individual firm used only one plant growth regulator (Table 7), while bedding plant and floriculture producers used a greater diversity of these chemicals (2.7, 1.9, respectively).

Soil fumigants are no longer used nearly to the extent that they once were, since most growers now purchase sterilized growing media. Only 4 percent of growers used any soil fumigant. Two percent of firms used steam, and 1 percent used methyl bromide/chloropicrin.

Pest Management Practices

Integrated Pest Management. A list of 30 integrated pest management (IPM) practices were identified as potentially appropriate for use in Florida's ornamental nurseries. The percentage of surveyed firms that reported using each of these practices is summarized in Table 8. The most commonly used IPM practices were removal of infested plants or parts, alternating pesticides, inspecting incoming stock, elevating or spacing plants for air circulation, and using least toxic pesticides, which were utilized by 83 to 71 percent of firms, respectively. The least commonly used IPM practices included screening to exclude pests (21%), using mulches to suppress weeds (16%), monitoring pests with pheromone traps (13%), treating retention pond water (4%) and using sanitized water foot baths (3%).

Scouting. Management of pests in the nursery requires current and accurate information about the state of pest populations, in order to determine whether application of pest control treatments are appropriate, and what treatment is most efficacious. Scouting of nursery production areas to monitor pests is one of the keystones of Integrated Pest Management. Table 9 presents results of surveyed growers regarding their pest scouting practices. Most firms (90%) reported making observations during routine tasks in the nursery, however this is not truly scouting in the sense of IPM. Deliberate, scheduled observations of pests were reported by 42 percent of growers, while 12 percent used systematic sampling procedures to quantitatively assess pest populations. Only 3 percent of firms did not scout for pests in any way. Note that these response options were not mutually exclusive, so some firms indicated following more than one type of scouting practice. Two-thirds of firms reported that scouting was done more than once per week (Table 10).

Traditionally, many pest control treatments were applied preventatively according to a predetermined schedule, regardless of the presence of pests or perceived pest pressure. From an integrated pest management standpoint this practice is undesirable because it may often represent a needless use of pesticides. The alternative is to apply pest control treatments only when scouting indicates that pests are in fact present, or when season or environmental factors can be reliably used to predict pest occurrence (e.g. for diseases).Table 11 shows that both of these practices are still common in the nursery industry, however, for each type of pest, more firms applied control treatments based on the presence of pests. Use of the preventative schedule approach was highest for combating diseases (57%) since most fungicides are preventative rather than curative. In the case of herbicides, only the pre-emergent or selective types can be used in the pots or on crops. Control treatments applied on any basis were quite low for nematodes.

Biological Controls. Use of natural living predators or parasites to control pests is an important and growing area of integrated pest management. Use of biocontrols was reported by 15 percent of firms (37). Specific biocontrol agents used are summarized in Table 12. Predatory mites were the most commonly reported biocontrol agent used, and mites were the most common pest targeted by biocontrols. Other pests targeted by biocontrols included whiteflies, aphids, mealybugs, fungus gnats, scales, thrips, caterpillars, banana moths, shoreflies, nematodes, beetles, and root diseases. Palms and other types of tropical foliage plants were the most frequently mentioned crops on which biocontrols were used, however several types of woody ornamentals and flowering crops were also reported. The area treated with biological controls, area in which organisms were released, averaged 2.7 acres, and ranged as high as 25 acres.

Pesticide Container Disposal. Disposal of pesticide containers in a safe manner is an important practice for avoiding exposure of residual pesticides to non-target organisms and to humans who may be unaware of their dangers. Seventy five percent of nursery firms in Florida reported that pesticide containers were disposed of in municipal solid waste (MSW) collection containers, while 20 percent burned containers on their property (Table 13). Approximately two-thirds of firms (63%) indicated a willingness to take empty pesticide containers to a local recycling facility if it were available.

Pest Management Decision Making

The importance accorded to pest management in ornamental nurseries is reflected by the 80 percent of surveyed firms in which the owner or family member was reported to be the person responsible for making pest management decisions (Table 14). Professional managers or growers were responsible for pest management decisions in 33 and 24 percent of firms, respectively. These results were similar concerning the specific task of scouting, with owners or family members being the responsible person for 78 percent of firms, and employees for 49 percent of firms. Consulting services for pest management are a growth industry, but only 3 percent of firms relied on consultants, and 2 percent of firms used scouting services as of this survey.

Many factors may potentially come into consideration for determining whether to treat for pests. Survey respondents were questioned about their consideration of 10 possible factors, as summarized in Table 15 . The most important factors were pest population level, weather, degree of pest damage and pest population change, which were considered by 90 to 55 percent of firms respectively. Other factors were considered by 30 to 50 percent of firms, except labor availability (20%). A reasonable explanation for the low level of awareness about presence of predators/parasites (33%) and plant disease inoculum level (30%) may be that growers do not generally know how to recognize or identify these indicators.

The importance of seven issues for pest management in the nursery industry were ranked by survey respondents as shown in Table 16 . A composite index of importance was constructed by weighting the number of respondents ranking each issue first, second, third, etc., with higher weightings given to higher rankings. The most important issue for pest management was "improve control of pests", followed by "increase salable plants", and "reduce use of pesticides". Although "increase salable plants" had a higher number of first place rankings, "improve control of pests" had a higher composite score because of broad support in first, second, and third place rankings. Issues which were of less concern were "increase ability to work in the nursery", "reduce potential pesticide resistance", "lower cost of production", and "lower environmental impact".

Production Area, Systems, Crops, Sales, Employment and Costs

Production Area . A total of 3503 acres were reported under production by survey respondents, as summarized in Table 17. Area reported for greenhouse, open containerized, and open field production areas represented 28, 56, and 16 percent of the total area, respectively. A total of 209 firms (95%) reported having some greenhouse or shadehouse production systems, 196 (89%) had some open containerized areas, and 50 (23%) had open field areas. Tree crops had the largest area, representing 35 percent of the total production area, while foliage represented 26 percent, woody ornamentals (shrubs) represented 25 percent, bedding plants and floriculture crops together represented 10 percent, and liners and other crops comprised 5 percent. Production area per firm averaged 7.7 (+/- 1.5) acres, and ranged as high as 600 acres.

Nursery Product Sales. Total sales reported by respondents for 1995 were estimated at $138 million. A majority of respondents reported sales of less than $500 thousand (M), while some 6 percent of respondents had sales of $2 million (MM) or greater ( Table 18 ). Among the 42 firms that reported actual sales, the average was $1,208,660, and the maximum was $30MM.

Sales were analyzed by crop and production system specialty as shown in Table 19. Greenhouse, open container, and open field production systems accounted for an estimated 61, 34 and 5 percent of total sales respectively. Foliage was the most important crop with 47 percent of sales, followed by woody ornamentals (19%), bedding plants (12%) and trees (10%). Other and unspecified crops together accounted for 6 percent of sales.

Employment and Wages. Surveyed firms reported a total of 3460 fulltime employees, which represented an average of 15.6 employees per firm. The largest firm had 425 employees. A total of 304 fulltime employees, or about 9 percent of the workforce, were dedicated to pest management, averaging 1.4 per firm and ranging up to 15. Wages paid (not including fringe benefits) for pest control employees averaged $7.47 per hour, and ranged from $4.00 to $18.25.

Costs for Pest Management. Sixty percent of firms reported that total expenses for pest management, including materials, labor and equipment, represented 5 percent or less of their total direct costs of production, as shown in Table 20. However, 20 percent of firms reported that pest control costs were 16 to 20 percent of total direct production costs, and 1 percent of firms had costs greater than 20 percent.

Literature Cited

Dillman, D.A. and P. Salant, 1994. How to Conduct Your Own Survey. John Wiley & Sons, New York.

Hodges, A.W. and J.J Haydu, 1996. The changing structure of Florida's ornamental plant nursery industry, 1989--1994. Economics Report ER96-1, Univ. Fla. Food & Resource Economics Dept., Gainesville, 22 pp.

US Department of Commerce, 1993. 1992 Census of Agriculture, Vol. 1, Geographic Area Series, Part 9, Florida State and County Data . AC92-A-9. Economics and Statistics Administration, Bureau of the Census, Washington DC.

List of Appendices

• Appendix A. Summary of Survey Results by County.

• Table A1. Sales and labor measures, by county, Florida ornamental nurseries, 1995.

• Table A2. Production acreage, by county, Florida ornamental nurseries, 1995.

• Table A3. Percentage of firms using pesticides or biocontrols, by class, county and region, Florida ornamental nurseries, 1995.

• Table A4. Average number of pesticides used per firms, by chemical class, county and region, Florida ornamental nurseries, 1995.

Tables

The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other extension publications, contact your county Cooperative Extension service.

U.S. Department of Agriculture, Cooperative Extension Service, University of Florida, IFAS, Florida A. & M. University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, Dean.

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