Scouting for nursery and greenhouse pests takes skill and time. It’s a critical piece of any integrated pest management program. By scouting, growers detect insects and mites while the population is small. Researchers have discovered there are established economic and environmental benefits from scouting nursery crops, such as saving production costs and labor hours.

If your operation is seeing more than average pest pressures in any given growing season, make sure your scouting techniques are polished and you’re giving crews the proper training.

Scouting begins before a crop enters your operation. If you’re propagating, evaluate the entire greenhouse one month prior to the introduction of a crop. Look at weeds in and around greenhouses and hoop houses, drainage problems, algae build-up, overwintered plants and debris under benches. Crops growing in adjacent greenhouses or outdoors should be recorded. When a crop arrives, scouts should inspect one-third or more of the plants.

Section off your production area into manageable portions based on location, size and crop or variety and scout them separately. It is more practical to deal with blocks that are 10 acres or smaller and contain plants of the same variety, age and spacing. Walk a transect when scouting to ensure you view plants from the edge and inner portion of the block. Common transects are walking in an X or a W pattern to cover the whole field. Change the path you walk each time you scout to inspect new areas. Re-examine hotpots where you have historically encountered high pest pressure. Scouting weekly is recommended. If degree day tools or biological information is available to predict the emergence or arrival of certain pests, use them to gauge when you might scout more intensively.

One of the greatest allies a grower can use to be an effective scout and pest manager is historical and forecast weather data. Degree day models are available for many pests and can be tracked using locally accurate degree day information. Some models even use forecast data to estimate when important events, such as egg hatch, adult flight or spore release, will occur. This information can inform you of when to intensify your scouting for certain pests and disease, when to apply a pesticide to optimize treatment and when the ideal conditions might occur to apply a spray. Check with your local extension office for degree day models or visit http://uspest.org for a custom degree-day mapping calculator for 48 U.S. states.

Sticky cards and traps

Sticky cards should be in your IPM toolbox for pest detection. Blue cards may be more attractive to thrips (and even shore flies), but it’s more difficult to see thrips against the blue background. Yellow sticky cards are used to detect infestations of adult flying insects. Attach each card to a stake with a clothes pin. Another option is to glue two clothespins back-to-back. Attach one end of the clothespin to a stake and clip the card to the other clothespin. This will allow you to move the card upward as the plant matures. For general monitoring, attach sticky cards vertically just above the plant canopy. For fungus gnats, place cards horizontally just above the soil surface or lay them flat on rims of pots. Aphids and thrips tend to be caught on the bottom half of the traps. Leafminers are caught more often along the top, and leafminer wasps and whiteflies tend to be spread uniformly over the trap. Aphids tend to be caught in the middle vertical columns. Since insects are not distributed evenly horizontally across the trap, columns counted should be vertical towards the middle of the trap.

In greenhouse production, each yellow sticky card should be numbered and placed at the minimum rate of one card per 1,000 square feet. Space the cards equally throughout the entire range in a grid pattern. Place cards near all entryways and vents. Small greenhouses (less than 4,000 square feet) can be scouted as one unit. Larger greenhouses should be divided into 2,000- to 3,000-square-foot sections. Change the cards weekly and place new cards in the same areas of the production area to track pest trends.

In outdoor production, traps should be hung at 4-6 feet above ground level in the nursery but can be placed at the office or other convenient location nearby. Traps can also be hung from limbs of trees in the nursery if duct tape or another protective coating is used to prevent bark damage.

Use one trap per insect species. Traps for different insect species should not be placed close to one another; place them at least 30 feet apart. To prevent cross-contamination when placing lures for more than one species, do not handle lures. The compounds in pheromone lures can penetrate many substances. Use disposable gloves, disposable forceps or shake lure out of the packaging onto the trap. Trap results can vary with location and microclimate; therefore, it is best to place more than one trap for a given pest in the nursery. Use at least one trap per 20 acres per insect species. Store extra lures sealed in the refrigerator or freezer. Replace lures during the season according to manufacturer’s recommendations.

Monitoring and keeping records

Begin inspections at the bottom of the plant and proceed upward, from older leaves to younger leaves to new growth. Special attention should be paid to buds and blooms. Pots should be tipped sideways for inspection of the underside of the leaves where many pests reside. Root examinations should be performed on crops that are highly susceptible to root disease by inverting and removing the pot.

Identify and record pest numbers in a notebook. Compile weekly summaries and itemize information for each greenhouse, hoop house or nursery bed according to the pests detected, the counts, and any unusual circumstances found.

Detailed records of any pesticide application should be kept to compare with previous records to see if fewer applications have been made or if a less toxic chemical has been substituted. These records should include the following information:

1. Date of spray application.
2. Name, classification, amount of active ingredient, and registration number.
3. Amount of material and water mixed for the application.
4. How much of the pesticide was applied.
5. Where the pesticide was applied.
6. Square feet or number of pots treated.
7. Type of application method (wet spray, fog, etc.).
8. Applicator’s name.
9. Labor hours.

Over time, population trends will emerge and provide direction for your pest management program.

Sources: University of Connecticut Extension, Leanne Pundt, (bit.ly/pest_scouting); Oklahoma State University Cooperative Extension, Mike Schnelle and Eric Rebek, (bit.ly/greenhouse_scouting); Michigan State University Extension (bit.ly/IPM_Scouting); University of Tennessee Extension (bit.ly/Monitoring_Scouting).

Consult and follow pesticide labels for registered uses. If any information is inconsistent with the label, follow the label. UConn Extension does not guarantee or warrant the standard of any product referenced or imply approval of the product to the exclusion of others which also may be available. UConn Extension, UMass Extension, OSU Extension, Michigan State University, and the University of Tennessee Extension are not endorsing any product or company.

Photo courtesy of CP Lab Safety

Proper pesticide storage can prevent accidents that could cause property or environmental damage. Check with local regulators for the requirements in your state.

A well-designed storage facility has four components:

• A storage cabinet, room or building
• A mixing area
• An area for loading and rinsing spray equipment
• A place to store and secure equipment and records, including MSDS and an emergency response plan

Storage

The best location for storage is in an area that isolates chemical fumes and dust from employees. This is often a separate building protected from flooding and the potential of fire from other buildings. Some states have regulations that restrict the distance the storage is located from surface water, public water supply, private wells and farm buildings. If a storage cabinet or room is located in the headhouse, place it away from the office and work areas. Place it along an outside wall so ventilation can be provided.

For small quantities, a steel cabinet is all you need, and it should have a containment area in the bottom to catch any spills or leaks.

For larger quantities, a storage locker is a good choice. These are waterproof structures that can be located either inside or outside. Most are made in a modular size so they can be expanded. They also have floor containment and a ramp for access.

Cabinets and lockers can be purchased as fire-rated or non-fire-rated units. Before making a purchase, review Material Safety Data Sheets to determine if the stored pesticides are flammable. If so, the storage cabinet should be UL-rated or Factory Mutual System approved. This will lower insurance costs.

Environment control

Pesticides should be stored between 40^° and 90^° F. A small electric heater with a thermostat and fan works well to maintain the temperature above freezing in a small unit. A hot-air furnace may be needed in a larger facility.

Good ventilation removes excess heat, chemical vapors and moisture from the storage area. Install a two-speed fan, ducted to the outside. Operation at a continuous low-speed rate of about one room volume change per hour helps prevent a buildup of toxic fumes. The higher rate (about six air changes per hour) can be activated together with the light switch when the area is occupied.

A motorized intake shutter about 1.5 times the fan area should be installed in the wall opposite the fan. It should open when the fan turns on. A relay that turns off the furnace when the fan is on should be installed.

Mixing and loading

Locate the mixing area near where the pesticides are stored. If it is inside the headhouse, provide an isolated room with ventilation. The mixing area should contain a work surface with measuring equipment. A water supply and sink are needed for chemical preparation and clean-up. Install a fume hood over the mixing table to draw fumes away from the person preparing the spray material.

The base of the loading area is usually constructed of concrete with a watertight surface impervious to chemicals. A surface coating of epoxy is used to seal the concrete. A berm around the base should be installed to provide containment and provide a volume of 110 percent of the capacity of the largest sprayer.

A sump should be installed in one corner to collect any spilled material. The liquid can be pumped to a storage tank for use in subsequent applications. Portable containment pads made of vinyl or nylon-reinforced elastomer are available. They should be placed on a level surface while filling or cleaning equipment.

A drench shower and eye wash should be nearby.

A pesticide spill kit with absorbent mats, pillows, granular absorbent, hydrated lime, sodium hypochlorite and a drum patch kit should be on hand for small spills. A broom, shovel, squeegee, plastic pails and bags will help in cleanup.

John Bartok Jr. is faculty emeritus, University of Connecticut, Department of Natural Resources Management and Engineering, jbartok@rcn.com

Nursery Management spoke to Dr. Norman C. Leppla, professor and program director, IPM at the University of Florida’s Entomology and Nematology Department about questions to ponder when considering biocontrol options.

Nursery Management: What is the one of the main points that growers should consider before beginning a biocontrol program?

Norman Leppla: Choosing a well-established supplier with a solid track record of serving customers is of utmost importance. Excellent customer service will be key as you begin and go through a biocontrol program. A good supplier will make sure you’re using their products appropriately. They’ll be upfront about availability and cost. And they’ll provide descriptions of target pests and their biology, as well as recommendations for applying and evaluating their products. They should provide the habitats and seasons in which the pests are encountered, developmental stages that are susceptible to parasitism or predation and relevant behavior of the natural enemies. 

NM: What is the first step when considering or adopting a biocontrol program?

NL: The first step is commitment and trying it one season is not enough. That’s another reason you need good-quality customer service from your suppliers. You must commit to a different system that involves cultural practices; sanitation (you must control the movement of things in and out of the greenhouse, including people); scouting; and being very careful of the source of your plants. You must commit to a system that’s biologically based and integrated.

NM: What are some common mistakes that growers make when adopting a biocontrol program?

NL: There are two mistakes that often occur – growers only conduct short-term trials. Like I said, trying it only one season is not enough. The other is when a grower takes the DIY approach and doesn’t enlist the help and expertise of their suppliers or when they try to rear their own natural enemies. I know a few growers who rear their own natural enemies, but it takes time to gain the experience.

Another common mistake is when a grower thinks of biocontrol as the same system as chemical control. They may think they’ll just remove the chemical and just add the biological, which is not the case whatsoever.

NM: Once a grower receives natural enemies from a supplier, what should they do first?

NL: Sometimes temperature extremes or other problems occur during shipping, so growers should open packages immediately to detect any potential issues and to provide a more hospitable environment for the natural enemies. Look for condensation or a fermenting smell, and the number of living and dead organisms should be estimated.

NM: What else would you like growers to understand about biocontrol programs?

NL: First, it works. It’s not a myth or something for odd characters. It’s mainstream and it can work for you. In an IPM program, there are times and a place when you need to use a chemical intervention. I’m not opposed to pesticides at all but be aware of their impact on natural enemies.

There are market advantages to using biocontrol including health benefits, no regulatory concerns, and, in the long run, it can be a whole lot easier and less expensive.

Effective resistance management involves judicious selection and accurate application of pesticides, and integration with other sound pest management strategies.

To minimize the prospect of arthropod pest populations developing resistance, follow these guidelines:

• Scout crops regularly and time pesticide applications to target larvae and adults.
• Implement sound cultural practices and good sanitation with prompt weed removal.
• If feasible, screen greenhouse openings to prevent insect pests from migrating into greenhouses.
• Use biological control agents or natural enemies.
• Use synergists when applying pesticides to inhibit detoxification enzymes.

Read the label to determine whether a synergist has already been incorporated into the formulation. Certain demethylation inhibitor fungicides and plant growth regulators may act as synergists by blocking the same enzymes as the conventionally used synergist, piperonyl butoxide. Certain insecticides also may be used as synergists when mixed together.

• Rotate pesticides with different modes of action.
• Use pesticides with broad modes of activity, such as insect growth regulators, insecticidal soap, horticultural oils, selective feeding blockers, beneficial bacteria and fungi and microorganisms.

Rotation

In developing a resistance management program, it is important to rotate common names (active ingredients), not trade or brand names. It is important to rotate pesticides with different modes of activity from the Insecticide Resistance Action Committee (IRAC) groups, not just active ingredients or chemical classes. This is because some chemical classes have similar modes of activity. “Mode of action” or “mode of activity” refers to the specific target affected in an arthropod pest. The classification of an insecticide or miticide is listed by its IRAC label designation. For example, organophosphates and carbamates, despite being different chemical classes, have identical modes of activity. These chemical classes block the action of acetylcholinesterase, an enzyme that deactivates the neurotransmitter acetylcholine and results in total loss of nerve function. Using acephate for two consecutive spray applications during a generation and switching to methiocarb would not constitute proper rotation.

Although acequinocyl, pyridaben and fenpyroximate are in different chemical classes – napththoquinone, pyridazinone, and phenoxypyrazole, respectively, all three are active on the energy production system and should not be used in succession. The neonicotinoid chemical class contains a number of insecticides including imidacloprid, thiamethoxam, acetamiprid and dinotefuran. Neonicotinoid-based insecticides have similar modes of action, so it is essential to avoid using them in succession. It is recommended that an insecticide with a different mode of activity be used before using a neonicotinoid-based insecticide. Rotation schemes based on IRAC groupings are not fail-safe for avoiding resistance. They only take mode of action into account, not mode of detoxification.

Another essential strategy is to rotate pesticides with specific modes of activity with those having non-specific or multiple modes of activity, such as insect growth regulators, insecticidal soaps, horticultural oils, selective feeding blockers, beneficial bacteria and fungi, and microorganisms. It is also important to rotate insect growth regulators with different modes of action because certain insect pests have demonstrated resistance to a number of insect growth regulators. In general, modes of activity should be rotated every two to three weeks, or within one to two arthropod pest population generations. Timing will depend on the time of year because temperature influences life cycle duration from egg to adult. Combining or tank-mixing pesticides with different modes of action may delay resistance. Arthropod pests in the population resistant to one or more pesticides would likely succumb to the other pesticide in the mixture. This approach, however, risks selecting for detoxification mechanisms that may permit survival to both pesticides.

The author is a professor and extension specialist in horticultural entomology/plant protection in the Department of Entomology at Kansas State University. rcloyd@ksu.edu or 785-532-4750