How to write a crop scouting report

What to check before entering the field

Confirm the grower, field name, crop, planting date and purpose of the visit. Bring the previous report, planting record and known problem locations. Ask about recent applications and follow the applicable entry restrictions. A routine monitoring visit and a visit to diagnose a specific patch can share a report, but they need separate samples and conclusions.

Bring a measuring tape, plant counter, hand lens, bags for specimens and the current local extension guidance for likely pests. Check the phone battery and prepare offline maps before leaving coverage. In PropelMapper, open the place you intend to visit and confirm its outline. A familiar field name is not enough when two growers use the same local name.

Write the question before collecting data. “Are cut plants present in emerged corn?” sets up a different method from “Has the soybean aphid population increased since the last visit?” The sampling unit, crop stage and comparison date need to answer that question. Record uncertainty immediately rather than hoping a photograph will resolve it later.

Sampling corn and soybeans without patch bias

Plan stops across the area you intend to describe, including changes in slope and soil. Follow the pest publication’s method when it specifies locations or sample numbers. Do not select every stop because damage is visible from the lane. Keep an additional directed stop for the wet corner, thin stand or visibly injured margin.

At each stop, record a stop ID, location, crop stage, sample unit and raw observations. For plant counts, retain row spacing and measured row length. For insect counts, retain the number of plants inspected and the number affected. For leaf injury, say how leaves were selected and which canopy positions were represented. A percentage without its denominator cannot be checked.

For early corn black cutworm scouting, Iowa State’s Scouting for Black Cutworm in Corn specifies examining 10 plants at each of five locations, for 50 plants total. Check for leaf feeding and cut plants, then search near injured plants for larvae. Keep the count of cut plants separate from the count showing leaf feeding. Measure larvae when using a size-dependent threshold.

Take a view of the surrounding crop before close-ups of an insect or lesion. Record the specimen ID in the note if material goes to a diagnostic lab. Mark identification as pending until it is confirmed. Leaf discoloration alone does not establish a disease, nutrient shortage or herbicide injury.

Pest checks by crop and stage

Use the following as a starting list for a Midwest corn and soybean visit, then add local risks from your extension service. These are separate scouting questions, not interchangeable treatment rules.

Source: the corn checks follow Iowa State’s black cutworm method and University of Minnesota’s corn rootworm scouting guide. The soybean checks follow Iowa State’s defoliation guide and Minnesota’s aphid guide. Weed escapes and disease symptoms also belong in the visit record, with identification and local guidance before advice is finalized.

Thresholds and return intervals to include

For black cutworm in Iowa corn, Iowa State gives a generic threshold of 2 to 3 percent cut plants when larvae are less than three-quarters of an inch long, and 5 percent when larvae are larger. Iowa State recommends scouting every 7 to 10 days until V5, beginning several days before predicted cutting dates. Keep larval size, live larvae and plant stage with the injury count. Check the current local recommendation before selecting a rescue treatment. Source: Iowa State, 2021.

For soybean aphids through R5, Minnesota requires an average of 250 aphids per plant, more than 80 percent of plants infested, and increasing populations. Minnesota recommends weekly scouting of infested fields, beginning in mid to late June and continuing until R6.5. The treatment rule applies through R5 rather than R6. Do not substitute the speed-scouting classification for a whole-plant average. Source: University of Minnesota, reviewed 2023.

Iowa State uses 30 percent soybean defoliation in vegetative stages and 20 percent in reproductive stages, applied to the field rather than its worst edge. Estimate missing leaf area throughout the canopy and verify that the insect causing current injury is still present. Local recommendations may differ; identify the publication and stage used in this particular report. Source: Iowa State, 2022.

A rootworm beetle count for next season’s management is a different decision from a silk-clipping assessment for current pollination. Minnesota describes weekly whole-plant beetle scouting until silks have dried and uses different methods for different purposes. Name that purpose before quoting a beetle number. An unqualified “rootworm threshold” leaves the grower guessing which action it supports. Source: University of Minnesota.

Worked example: an aphid visit in PropelMapper

Start the visit at the correct place in the phone app. Say the crop stage, whole-plant method, stop IDs and counts in the voice note. Capture photos of aphids and the surrounding crop. Keep the raw counts in typed notes or readings so a reviewer can reproduce the arithmetic. Configure the relevant metric types in Settings, Metric types if the team wants those readings organized in Metrics.

After the phone reconnects, review the transcript, extracted readings and draft report. Correct the field name, stage, counts and units against the recording. Add the source link and the advisor’s recommendation. Create a Follow-up task with an assignee and return date. Review and sign the report before sending it; the recipient’s acknowledgment confirms receipt rather than agreement with the agronomic decision.

Writing the grower’s summary and next check

Lead with the decision, then explain its evidence. Name the sampled area, any directed stops excluded from the average and any portion not inspected. A damaged patch can justify its own follow-up even when the representative field sample is below a threshold. Give that patch a location and a separate conclusion.

When identification or trend is unresolved, say what evidence would change the recommendation. The next person should know whether to repeat counts, collect a specimen, inspect roots or check a returned lab result. The crop scouting form holds the detail; the opening paragraph should make the requested action clear without requiring the grower to interpret every sample row.