Scout/Management Negotiations

SCOUTS ARE PRESENTLY in use in all major plant commodities within the United States. These scouts are successful by virtue of careful negotiations with employers so that the expectations of management are matched with the realities of scouting. Scouts provide an array of services that include:
  1. scheduled, systematic monitoring
  2. plant problem sampling and diagnosis
  3. disease/pest management advice
  4. nursery situational scouting
  5. posttreatment pesticide evaluation
  6. IPM record keeping
  7. nursery mapping
  8. educational training

    These functions are often combined into one of the following service level offerings. Generally speaking, three major levels of scouting are commonplace across various crop commodities:

    Level 1 is characteristic of the service level of an internal scout and most typifies past use of scouts by the ornamentals' industry. This level of scouting has a significant level of failure since the scouting benefit of early detection is often lost as responsibility for problem diagnosis falls back to nursery management. Level 2 scouting is the most efficient service level as problem detection and diagnosis are related tasks that can easily be managed by the same individual -- the scout. Level 3 is essentially the service offering of a crop consultant company and normally requires more than one person as well as considerable experience in the horticultural industry to risk the legal liability of cultural and pesticidal recommendations for plant problem management.

    The potential scout must negotiate clearly with nursery management so that scouting expectations can be affordably met. Three major areas must be discussed and mutually agreed upon by scout and management.

  1. scout service level
  2. frequency of scouting
  3. key plants: key diseases/pests
  4. related services
  5. nursery modifications to support scouting
    The scouting service level that includes both routine monitoring and plant problem collection and diagnosis is the most expedient and efficient service offering for the commercial ornamental plant industry. This does not preclude the effectiveness of a scout service level that focuses on problem detection only. Many growers as well as scouts can competently identify common insect/mite pests with the use of a hand lens or dissecting microscope. These same individuals can be quite accurate with common foliar diseases as well, especially where the host is known and plant symptoms are carefully examined. There are, however, many instances of pest/disease variation in the nursery as well as the occurrence of new problems including those caused by abiotic factors such as nutrient imbalances or weather conditions. These plant problems will not be easily identified by visual examination alone. Remember the underlying premise to the successful IPM program: early detection and accurate identification of disease/pest problems.    

    All scouting service levels involve systematic nursery inspection for plant problems.Therefore all scouts need to define the type(s) of scouting data expected by the nursery ownership and the format of that information to be submitted. The return from monitoring activities will vary with the data collected by the scout. Scouting data can be as simplistic as "unhealthy juniper plants in bed #4" to a detailed account such as: "Photinia fraseri (bed #6) -- aphids present (60% of plants) -- ladybugs (adults/larvae) present -- leaf spot (15% of leaves) on 45% of the plants." Agree on the following points dealing with scouting:

  1. Type(s) of data -- qualitative vs. quantitative or both?
  2. Data recorded on data sheets, nursery maps, or other?
  3. Both nursery and scout should have copies of data at day's end; use carbonized forms, carbon paper, photoduplication?

    Scouts operating at Level 2 must also define the procedures for the collection of plant problem samples and their processing for accurate diagnosis. The following questions need to be discussed before work begins:

    Those scouts employed as part of a crop advisory service are likely functioning at Level 3. Is the scout empowered to answer problem management questions on site or are these referred to someone else in the company? Does the management advice result in the issuance of a "recommendation" or a selection of management options? Are the management suggestions independently derived or are they based upon Cooperative Extension issued documents? Is advice given for visually diagnosed problems or only those defined by suitable diagnostic facilities? These questions have more significance to the scout as they affect the level of legal liability incurred through the issuance of management options.

    The issue of scouting frequency seems straightforward. The interval for inspection of key plants is dependent upon the production cycle and, often, the time of year. Short-cycled crops, as with plug production of bedding or vegetable plants, may require a two-to-three-day scouting frequency, while woody ornamentals may fall into a two-to-three-week cycle. Some plant production is tied to seasonal marketing periods and, thus, may have accelerated inspection cycles as the sales period approaches. Other nursery situations may only require scouting during the period of active sales and suspend this activity during the late-summer and fall propagation period.

    Affordability of the scouting effort is directly correlated to the "key plant: key pest/disease" concept. Intense scouting of every block of every plant species in a nursery is usually unaffordable. The scout and the nursery grower/owner need to choose those species with both a history of plant problems and a significant level of production volume in the nursery. Key plant: key pest choices should be derived from in-nursery records for those plants grown in that geographic area.

    If nursery records of problem diagnoses are unavailable, advice can be obtained from local county extension staff, other experienced growers, or the summary list of key pests/diseases for the more important ornamentals grown in Florida provided in Chapter ( ). Remember that the scout activity is to be focused on high-risk plant species each visit, with the rest of the nursery being overviewed over two or more visits in a more cursory manner. Lists of key plants should be renegotiated seasonally or yearly, depending upon changes in the plant mix in the nursery.

    At the start of Level 1 scouting in a nursery, it may become apparent to the nursery management that certain other scout-offered services may be useful to nursery. For many nurseries, the implementation of scouting cannot proceed without a serious mapping exercise done by either the scout or some nursery employee. This map provides a letter or number identity to every plant-related area in the nursery. It also imposes a consistent identification system for beds within blocks, houses within ranges, benches within greenhouses. The immediate benefit is that all problems defined by the scout can be quickly located by any employee. The map exercise can also serve to document irrigation line placement, drainage tiles, electric service, etc. for future maintenance needs.

    Nurseries operating at Level 3 scout service may desire scouts to assess the efficacy of management advice, particularly pesticide applications. Although this may require some additional scouting time, it serves to underscore the value of a correct diagnosis prior to treatment and may also uncover a more complex plant problem affecting particular plants by the lack of expected response to treatment.

    Once a nursery has passed a year or more enrolled in an IPM program, data collected by scouts tends to accumulate. Assigning some scout time to data organization and analysis can provide some predictive information on disease/pest outbreaks on certain plants. Incidence of particularly damaging diseases or pests can be plotted on a calendar as to first appearance and duration. This allows for more timely preventative activities.

    As scouts gain expertise, they can also offer to conduct a situational scouting exercise over the entire nursery in an effort to objectively assess horticultural deficiencies that may exist on site that correlate to pest/disease occurrence [see Chapter ( )]. The first years of data collection can also provide some excellent educational opportunities for nursery employees. Scouts can be encouraged to photograph the more common plant problems, perhaps even compile a dried, pressed disease collection or an insect pest/beneficial collection for use by nursery employees in educational training.

    The last point for negotiation is a measure of the nursery's resolve to make the scouting routine as efficient as possible. All nurseries can modify various production practices to improve scouting efficiency and thus scouting affordability. The following production modifications have a direct impact on scouting affordability for problem detection:

  1. Establishment of a plant isolation/quarantine area.
  2. Fewer, larger propagation cycles per plant species.
  3. Deployment of plants of the same species into fewer nursery sites.
  4. Grouping related species into the same nursery block or greenhouse
  5. Careful scheduling of pesticide applications to avoid scouting conflicts with worker re-entry intervals for specific pesticides in nursery sites.

    Any nursery that buys stock or propagules from other companies should provide a holding area where this plant material can be scouted for at least two weeks before dissemination throughout the nursery. This provides the scout with the best opportunity to define potential plant pest/diseases problems before there is opportunity to spread to clean blocks of plants.

    Larger propagation cycles per plant species can improve monitoring efficiency of propagation areas. This can also improve scouting efficiency in the production area by the subsequent placement of fewer, large blocks of a plant species. Problem management in these larger blocks can also be more efficient. Similarly, grouping plant species of the same genus or several genera of the same plant family with known, shared "key pests/diseases" can improve chances of early detection and subsequent management efforts. Entomosporium leaf spot, for example, is a shared disease of Photinia, Raphiolepis and Eriobotrya spp. -- all in the Rosaceae family. Blocking these genera together will improve disease detection and subsequent utility of such cultural controls as day watering cycles.

    Lastly is the issue of Worker Protection Standards compliance. Scout employment should result in the careful timing of preventative or curative pesticide applications to nonscouting intervals. Scouts should not be placed in pesticide exposure situations nor prevented from completely scouting key plant areas of the nursery. Poor scheduling of pesticide applications will result in higher scouting costs.

    Conscientious negotiations between scout and nursery management will insure realistic expectations for the scouting activity and provide the best environment for program success.

Physical factors Chemical factors Biological factors


(chilling or freezing)

Excess (heat stress)




Radiation (light)



Quality imbalance

Duration (photoperiod)

Mechanical forces














Plant growth regulators

(excluding herbicides)


Pathogenic bacteria

Pathogenic fungi

Pathogenic viruses and virus-like particles

Pathogenic nematodes

Injurious insects

Injurious mites

Injurious slugs or snails

Injurious rodents, birds and other vertebrates

Competitive weeds

Other destructive or

competitive organisms

Figure 1. Categories of plant stress factors found in the commercial nursery environment.