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Pest, Disease & Weed Timing CalendarsPest Scouting Calendar for Orchards
Orchard pest timing runs on tree development and accumulated heat, not on a date. Here is how to build a scouting calendar around both.
Key points
- Anchor orchard scouting to tree stage and degree days, not calendar dates.
- Set traps early and record the biofix for pests that use one.
- Sample a fixed number of trees and fruit across each block.
- Keep trap logs and degree-day tallies and use a weather station near your site.
Why do orchards scout by growth stage and heat?
Fruit trees pass through dormancy, bud swell, bloom, petal fall, fruit set and ripening on a schedule set by weather, so the same stage can arrive weeks apart in different years. Insects respond to the same weather. Because both follow temperature, extension orchard programs link scouting to tree stage and to degree days, a running total of heat that tracks insect development.
That is why a date list copied from a neighbor or last year's notebook can mislead you. Anchor your calendar to stages and heat accumulation, then write dates in afterward as a record.
What is a biofix and why does it matter?
A biofix is a biological starting point, such as the first sustained catch of a moth in a pheromone trap. Degree days are counted from that point, which lets you predict when eggs will hatch or the next stage will appear. Extension fact sheets on codling moth, such as those from Kentucky and Utah State, describe this approach in detail.
Set traps before the expected flight starts, check them on a regular schedule and record the first sustained catch. Your extension fruit specialist can tell you which pests use a biofix in your region and which degree-day model to follow.
What should you check at each stage?
Dormant season checks look for overwintering stages on bark and buds and for damage from last year. Around bloom, concerns shift to early season insects and pollinator protection. After petal fall, fruit-feeding insects and foliage pests become the focus. Later, scout fruit for damage and check for pests that build up into late summer.
Match each stage to a short checklist from your extension tree fruit guide, and keep it in a weatherproof folder or on your phone.
- Dormant: bark, buds, previous damage
- Bloom: pollinators present, protect them
- Petal fall to fruit set: early fruit feeders
- Summer: fruit damage, foliage pests, traps
- Harvest: damaged fruit counts for next year
How do you sample trees and fruit?
Pick a fixed number of trees spread across each block and a fixed number of fruit or shoots per tree. Sample from different heights and sides, since pest pressure often varies around the canopy. Keep blocks of the same variety and age together when you can, because fruit stage differs among varieties.
Count damaged fruit as a percentage so you can compare week to week and block to block.
What records and tools help?
Keep a trap log, a degree-day tally and a block map with scouting notes. Many states offer weather-station networks and online degree-day tools; Washington State University and Utah State University both publish degree-day resources for tree fruit. Use a station near your orchard, since heat accumulation varies with elevation and slope.
Always confirm any treatment decision with local recommendations. The label is the law, pre-harvest intervals vary by crop, and bees are active during bloom. State licensing rules for applicators differ.
What does a worked example look like for an apple block?
For example, suppose a grower has a block of apples and sets two pheromone traps for a moth pest before the expected flight. The traps are checked twice a week, and the first date with a sustained catch becomes the biofix. From that date the grower adds daily degree days from a nearby weather station and compares the running total to the egg hatch point listed in the extension fact sheet. Scouting of fruit begins as that total approaches the published stage.
The point is not the specific numbers, which differ by region and variety, but the method: trap, record, count heat, then scout at the predicted stage. Your extension fruit specialist can supply the model and totals for your area.
Mixed plantings, such as a home orchard with several kinds of fruit, still benefit from the method. Choose the one or two pests that cause you the most trouble, trap for those and use the same heat-based approach.
How do bloom and pollinators change the calendar?
Bloom is the point in the calendar where scouting and pollinator protection overlap. Honey bees, native bees and other pollinators are working the flowers, and many pesticide labels restrict use during bloom. Plan your scouting so that any decisions needed around bloom are made before flowers open, and keep a record of what is blooming in the orchard floor cover as well.
Mow or manage flowering ground cover according to your extension advice so that bees are not drawn to treated areas. When in doubt, ask before you act.
Sources and further reading
Last reviewed: November 2026. Educational information, ranges only. Confirm timing with your county extension office.