Scouting for Landscape Plant Problems: An Integrated Pest Management Approach

What is IPM and how can it help to keep my plants healthy?

Integrated Pest Management (IPM) is a collection of approaches and solutions to avoid, prevent and manage pests, such as insects, diseases or weeds. For more information on IPM, check out the publication: “Integrated Pest Management for Home Gardens and Landscapes,” or for additional resources visit ipm.iastate.edu.

Scouting, or monitoring plants often, carefully and systematically with the goal of spotting problems early, and diagnostics are the foundations of IPM. Monitoring for pests is the first and most critical step in preventing pest damage. Scouting should begin as soon as plants begin to grow or when pests become active. It should continue until plants are dormant or the risk of the pest has passed.

No pest—insect, disease or weed—is the same. They can be harmful in different population sizes, cause a variety of symptoms on plants, and impact the health of the plant differently. The information gathered from scouting gardens and landscapes can help you decide whether you may need to take additional steps to manage the pest.

Before you scout:

Learn about the plants you are scouting. Learn what type of plant is it and what is normal for the plant. You must know what is normal to notice that something is wrong!

What to look for:

When scouting, it is important to record what you observe either in writing, pictures or even video. Keeping a scouting or garden journal is a great way to keep accurate track of your observations. It becomes a record that can be referenced year after year.  

Here are some things you should look for when scouting that often indicate a problem:

• Cupped, chlorotic, spotted or malformed plant parts
• Discolored, damaged, swollen or sunken leaves and stems
• Pockets of less vigorous or dying plants
• Frequency and numbers of insects
• Anything out of the ordinary

For more symptoms and evidence of pests to be on the look for, read the publication: “Identifying Tree Problems.”

Scouting for diseases includes monitoring weather (rain, humidity and temperatures), walking the landscape to inspect foliage and bark on the trunk and limbs for symptoms and frequency (percent of the plant infected) that can indicate changes in pathogen pressures.

Scouting for insects involves properly identifying the insect, knowing the insect’s life cycle (egg, immature or adult), habits and when it causes plant damage.  Information from scouting allows you to determine how many pests there are and if you need to take action.

Tools for Scouting

• Camera for taking pictures
• Knife and pruners
• Hand lens for inspecting small insects, mites, insect eggs or feeding damage
• Containers for collecting plant, disease and insect samples
• Small cooler for transporting and preserving samples
• Beating tray or scouting board to collect and count pest and beneficial insects
• Reference materials for helping identify pests
• Iowa State University Plant and Insect Diagnostic Clinic submission forms has fields that will help you observe the situation, identify patterns and collect information, the form is free to download at clinic.ipm.iastate.edu

Scouting methods:

To make the best use of time-spent scouting, section the area into manageable portions based on location, size and plant type, and scout them separately. For best results, scout areas in “X”, “W” or diamond patterns, and be sure to change patterns every time you scout.

A scouting journal, or garden journal, is extremely helpful when monitoring your plants in your garden. It will help keep accurate dates to different observations made in the garden, from the weather, and more. For more about starting a garden journal, visit the Flavors of Northwest Iowa Blogs.

Below examples of the type of information to collect in your journal:

• Plant, variety and date planted
• Notes (observation of symptoms or pest appearance, date observed)
• Date of observation
• Took photos: Yes/ No
• Performance/ status (overall look, increasing or declining symptoms, prolific/invasive)
• Pest noticed
• Management tactics employed
• Efficacy of tactics (would I use this tactic again?)

In all cases and if possible, scouting includes reviewing records of previous scouting efforts, management decisions taken and how effective they were.