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A good pest-monitoring program can help growers keep the cost of pest control down while also minimizing the impact of pests on the fruit and trees, says integrated pest management consultant Astrid Goplen of Pasco, Washington.

A monitoring program can enable growers to develop a pest management program that will be dependable in both the long and short term, she said during a Washington State University Fruit School this winter. The goal of monitoring is to empower the orchard owner or manager in their pest management decision-making.

Monitoring begins with scouting and collecting data in the orchard. That data then needs to be interpreted to assess the need for pest controls, so that a decision can be made.

Typically, the grower and consultant work together on decision-making, but because of the increasing complexity of pest control, the consultant may need support in terms of monitoring in the orchard. Monitoring can involve a whole team of people, including the grower, manager, orchard employees, field horticulturists, and consultants. Their individual roles need to be defined, and those may vary from orchard to orchard, Goplen said.


When developing an in-house monitoring program, the grower or manager needs to identify the right kind of employees to do the scouting, she said. Monitoring requires different search skills from hand thinning, for example. A good candidate might be someone who is not a crew boss, but is smart, shows promise, can work independently, and needs an extra challenge, Goplen suggested.

She has worked in scenarios where teams of women—wives of the foremen, for example—have worked as scouts. "They have maybe a little more focus on detail at times and don’t have that need to run through the orchard fast," she said.

Alternatively, a grower or manager can hire high-school students or their own children, if they’re interested in horticulture and pest management and are looking for an opportunity to learn while earning some money after school.

It’s important that scouts are dedicated to the job of scouting all season long and don’t have to break off to do other tasks such as frost control, hand thinning, or cherry picking, she stressed.

Members of the monitoring team need to be trained. Goplen said meetings of Washington State University’s Pest Management Transition Program’s implementation units are good learning opportunities. Other resources include the book Orchard Pest Management for the Pacific Northwest, which is available from the Good Fruit Grower or can be found online at http://jenny.tfrec.wsu. edu/opm; an Orchard Monitoring Manual for Pests by Naná Simone, which is available in English or Spanish at; and WSU’s on-line Decision Aid System at

Pest images from Orchard Pest Management can be printed out and posted on a bulletin board to help the scouts to identify pests and beneficial insects. Scouts can be assigned a "pest of the week" to look for.

The monitoring team needs to know:

• The pests of concern

• Which are the good insects that need to be conserved

• The insect life cycles and stages that are treated

• What the pests and beneficials look like in different life stages

• Which beneficial insects prey on which pests and how to conserve the beneficials

• How and when to monitor for the different pests

There’s a lot to learn, she said. Typically, scouts will work slowly at first but become more efficient as they are trained.

Trap catch

Goplen recommends designing a monitoring plan and sampling protocol at the beginning of the season. The team should communicate at least weekly about what scouts are finding in the orchard and what they should look for next, or about what’s been sprayed and what will be sprayed, so everyone knows what’s going on.

It’s important to have timely records on codling moth trap catches because that is an essential part of a pest management program, she said. Trap catch should be recorded weekly, starting at bloom.

With good trap catch data, it might be possible to treat only a portion of the orchard and get the problem taken care of economically, she said. She recommends using Washington State University’s online Decision Aid System ( for timing sprays.

Check fruit for codling moth injury at least once per generation, at about 75 to 100 percent egg hatch. Check hot spots and borders where the risk of damage is highest, and if you see problems, try to correct them. Were the pheromone dispensers hung correctly? Are extra traps needed? Are supplemental sprays needed? Is there a problem with spray coverage, perhaps because of a slope? Is the problem coming from outside?

Other pests

For other pests, review your scout notes weekly, she suggested, and make sure it jives with what you’re seeing in the orchard. Make some trips through the orchard to be sure you are not missing anything.

Leafroller larvae are easy to miss in the spring, and the number of leafroller adults caught in traps is not a good indication of the risk of fruit damage. However, leafroller trap catch reports are useful for making year-to-year comparisons to see if the numbers are increasing, she said. Look for leafroller larvae from July until the end of the season.

If it seems overwhelming to monitor for multiple pests, just focus on codling moth, Goplen suggested, and be as devoted to that as you are to making sure your tractor is working properly. Otherwise, you could be impacted economically because of lost fruit or lost markets, or spraying unnecessarily.

"If you don’t do anything else, stay on top of your codling moth monitoring program," she said. "Use at least three codling moth traps per ten acres and one additional trap per additional 2.5 acres."

At the end of the season, do bin sampling for codling moth and other pests. Harvest is a good time to check for leafroller problems and assess whether sprays have worked. Packing-house cull reports can sometimes help identify insect problems, but do not always accurately reflect what is happening in the orchard, she cautioned. For example, mechanical damage might sometimes be classified as insect damage.