Maintain scouting protocols even when it gets crazy this spring

Do you have pests in your greenhouse? How do you know? They were probably reported by a scout.

The first thing you need to consider when you think about scouting is who’s going to do it. Some growers have full-time scouts, some have part-time scouts, but for most operations, scouting is part of someone’s responsibilities — not an entire job description on its own.

“Don’t think you have to have a paid, titled, credential scout do the scouting,” says Timothy Malinich, horticulture educator with the Ohio State University Extension’s Erie County office. “Scouts can just be people that have been empowered to go out there and look for things, see those things and report them.”

Scouts could be site managers. If a greenhouse operation has multiple production houses, it could be the lead section grower of each. It could be all employees at the greenhouse. It could be the employees on the potting line or the ones managing inventory. In many cases, it’s the applicator.

Managers can empower everyone in their organization to scout. But you need to make it part of the job description. Scouting does cost time and, through that, money. You must give the people you are empowering to scout time to scout, and be flexible about when they do it.

Thomas DeHaas, another agriculture and natural resources educator at the OSU Extension’s Erie County office, knows one applicator who scouts when it’s raining. This is efficient use of his time, since you can’t spray when it’s raining. One of the best times to scout for scale is winter, since the branches aren't covered up with leaves.

You should also provide some basic training on what scouting entails. Though even without formal training, if an employee sees something that doesn’t look normal, they can report it and you can use it as a point of data.

DeHaas says every employee likely has one of the most powerful scouting tools right in their pocket: the smartphone. “They can take a picture and text somebody,” he says. “If you have a central person who gets that info, you’ve already improved your scouting program 100 percent.”

DeHaas suggests growers think outside the box to incentivize employees to scout in addition to their responsibilities. “If it’s worth doing, it’s worth paying for,” he says. “Giving people time to do it is going to cost you money, but it saves money too.”

SCOUTING TOOLS

The tools of the trade can vary widely in price and effectiveness. If you ask a large amount of your employees to scout, you won’t outfit all of them with Canon Rebels and pricey magnifying lenses. But everyone should at least have the basics listed below. Here are some options:

Basic tools: smartphone, loupe, pen and waterproof paper, pruners, marking tape, flags, acetone with cotton balls, hand sanitizer, map (to mark where pest was found).

Midrange tools: digital magnifier, EC/pH meter, clip-on lenses for smartphone (ex. CamKix).

High-end tools: microscope, “real” camera (D-SLR style), laptop for image manipulation, clip-on lenses like olloclip.

SCOUTING TIPS

Dr. Raymond Cloyd, a professor and extension specialist in horticultural entomology/plant protection in the Department of Entomology at Kansas State University, recommends growers implement these seven scouting strategies:

1. Start early.

Place colored (yellow or blue) sticky cards among crops as soon as possible in the spring and conduct visual inspections, which will help to avoid outbreaks. Check the sticky cards once per week, count the numbers of insect pests and record the number.

2. Position colored sticky cards appropriately.

In order to capture adult thrips (western flower thrips), whiteflies, shore flies and leafminers, place sticky cards just above the crop canopy, and attach to a bamboo stake with a clothespin, thus allowing the sticky card to be adjusted as the crop increases in height. However, in order to effectively capture adult fungus gnats, position yellow sticky cards horizontally near the growing medium surface, as this is where adults are most active.

3. Place sticky cards underneath benches with soil-based or gravel flooring.

Position yellow or blue sticky cards, or yellow sticky tape underneath benches to help capture and detect the presence of adult thrips, fungus gnats and shore flies, which will aid in determining if these insect pests are or have pupated in the gravel or soil.

4. Visually inspect plants.

Sticky cards (yellow or blue) will capture adult thrips (western flower thrips), whiteflies, fungus gnats, shore flies, and leafminers. However, mealybugs, scales, and spider mites, as well as, eggs, larvae, nymphs and pupae will not be captured on sticky cards. Therefore, it is important to check plant parts (e.g. leaves and stems) during routine monitoring to determine the presence of non-flying insects and various life stages.

5. Check the undersides of leaves.

Nearly all insect and mite pests and life stages are located on leaf undersides, so be sure to regularly check the undersides of leaves for the presence of non-winged aphids, mealybugs, scales and spider mites, as well as the eggs, larvae, nymphs and pupae of thrips, whiteflies and leafminers.

6. Maintain accurate records.

Always maintain records of your monitoring efforts by collecting information on 1) all major insect and/or mite pest problems during the growing season; 2) susceptible crops; and 3) location in the greenhouse — especially those areas near openings. Maintaining records will be helpful in allowing you to assess when and where “hot spots” occur.

7. Remove yellow sticky cards before releasing natural enemies.

Prior to releasing any parasitoids and/or predators, remove yellow sticky cards as the adults of many parasitoids and predators are attracted to yellow and will subsequently be captured.

These articles originally appeared in a past issue of Nursery Management magazine and were combined and edited for length.