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Pest, Disease & Weed Timing CalendarsStink Bug Calendar
Stink bugs move between hosts through the season, so your calendar should follow the crops they favor at each stage, from early spring to harvest.
Key points
- Stink bugs overwinter as adults and move from wild hosts into crops through the season.
- Scout edges near woods and buildings first, then fruit and pods at set and ripening.
- Use crop-specific thresholds from extension.
- Record first sightings and share them with your extension office.
How do stink bugs spend the year?
Several stink bug species damage crops in the United States, including native species and the brown marmorated stink bug. Adults overwinter in sheltered places such as leaf litter, wood piles and, for some species, buildings. They become active in spring as temperatures rise, feed on wild hosts, then move into crops as fruit and seed develop.
Females lay egg masses on leaves, and nymphs pass through several stages before becoming adults. Depending on the species and the climate, there may be one or more generations in a season.
For example, a grower who finds a few adults on early spring weeds near a woodlot should plan on weekly checks of the nearest crop rows once fruit begins to form, since that is the stage where feeding injury shows.
What does the early season check include?
In spring, look at the places where bugs would feed first: weedy field edges, wild hosts, ornamental trees and early crops. Check the crop edge next to woods, hedgerows and buildings, since overwintered adults often arrive from these sites.
Early detection helps you know when to increase scouting. Local extension alerts and, in some states, trap networks report first activity.
Wild hosts such as some trees and weeds can carry large numbers before cultivated crops are attractive, so what you see on them tells you about what is coming.
How do you scout fruit and vegetables?
Stink bugs feed with piercing mouthparts, which causes dimpling, discolored spots, corky tissue and distorted fruit. Look for adults and nymphs on fruit, pods and developing seed. Check the egg masses on the undersides of leaves. Use a beating tray or a sheet under branches and shake or tap to dislodge bugs.
Scout at fruit set and through ripening, when the crop is most exposed. Many tree fruits, peppers, tomatoes, beans, sweet corn and soybeans can be fed on, with different thresholds for each. Wear gloves when handling bugs if you are sensitive to their odor, and put collected bugs in soapy water rather than crushing them near the crop.
- Adults, nymphs and egg masses on leaves
- Dimples and corky spots on fruit
- Beating tray or sheet for tree crops
- Edge rows near woods and buildings first
Which tools help with timing?
Pheromone traps are used in some states to track brown marmorated stink bug activity. Black light and pyramid traps are used in research and monitoring programs. Degree-day models exist for some species, which your state extension service may publish.
If your state has an active monitoring program, use its alerts. If not, weekly plant checks at the right crop stage are the practical standard.
Keep a count of adults and nymphs separately. Nymph numbers tell you that a new generation has begun and that damage risk will be rising over the next weeks.
How do thresholds and natural enemies factor in?
Extension thresholds for stink bugs vary a great deal by crop, from a count per sample in soybeans to a percentage of damaged fruit in orchards. Use the number for your crop and state.
Parasitic wasps that attack stink bug eggs are present in many areas, and predators also feed on eggs and nymphs. Preserve them when you can by choosing timing and products with care and by following local guidance.
What can you do beyond treatment?
Manage wild hosts and weeds near crop edges where practical, plant trap crops where extension supports it and harvest promptly. Some growers use exclusion netting on high value crops. In fall, sealing buildings reduces indoor invasions by overwintering adults.
If you consider insecticides, the label is the law. Pre-harvest intervals apply, pollinators must be protected and applicator licensing varies by state. Your extension office can explain current local recommendations.
Trap crops need careful planning, so ask your extension office whether they have worked in trials near your area before you plant one.
What should you record?
Log first adult sighting, first egg masses, first nymphs and the date damage appeared on fruit or pods. Include weather and the crop stage. Over several seasons you will see which edges and which crops draw bugs first.
Share your records with your county extension office. Reports of new activity help them warn other growers. Photographs of damaged fruit with the date written on the back of each print or in the file name make it easy to compare years.
Sources and further reading
Last reviewed: November 2026. Educational information, ranges only. Confirm timing with your county extension office.