What to Watch in July: Your Crop Scouting Guide for Corn and Soybeans

When it comes to crop scouting, July is one of the most important months of the year. Corn is tasseling, soybeans are in early reproductive stages, and the conditions are just right for insects, disease, and nutrient deficiencies to show up across the field.

Whether you’ve already been out walking or haven’t had time to step between the rows, this guide covers what we’re looking for right now when crop scouting in July — and what signs might signal a need for action.

Key Insects, Diseases, and Nutrient Deficiencies to Monitor This Month

🌽 Corn: What to Watch When Crop Scouting in July

Corn is typically moving through VT to R1 in July, which makes it prime time for both fungal diseases and insect pressure. Watch for field patterning and threshold levels as you scout.

• Diseases:

  • Tar Spot – Small, black raised lesions (often after cool, wet periods)

  • Gray Leaf Spot – Rectangular lesions on lower leaves

  • Northern Corn Leaf Blight – Long, cigar-shaped lesions that may appear on mid- to upper canopy leaves

• Insects:

  • Corn Rootworm Adults – Beetles feeding on silks can interfere with pollination

  • Western Bean Cutworm – Check upper leaves and tassels for eggs or larvae

  • Japanese Beetles – Silk clipping and foliar feeding

• Nutrient Deficiencies:

  • Nitrogen – Yellowing on lower leaves, especially from midrib outPotassium – Yellowing and firing on leaf edges

  • Zinc/Sulfur – Streaking or chlorosis on newer growth

• Stand & Ear Development:

  • Plant and ear height uniformity

  • Tassel emergence consistency

  • Watch for goosenecking, leaning, or early signs of lodging

🌱 Soybean: What to Watch When Crop Scouting in July

Many soybeans are hitting R1–R2 this month, which puts them in a critical window for both disease management and insect protection. Look for yellowing or interveinal chlorosis in IDC-prone zones.

• Diseases:

  • Sudden Death Syndrome (SDS) – Yellowing and interveinal chlorosis

  • Frogeye Leaf Spot – Circular lesions with gray centers, purple margins

  • White Mold – Mycelium in canopy; look for sclerotia in humid, dense areas

  • Septoria Brown Spot – Small dark brown spots starting on lower leaves

• Insects:

  • Bean Leaf Beetle – Defoliation and early pod feeding

  • Soybean Aphids – Threshold is 250+ per plant and rising

  • Stink Bugs – Check flowers and pods

Bonus Tip: Dig a few plants and check for active nodulation — pink or red centers mean the plant is fixing nitrogen effectively.

🚩 Weed Escapes & Herbicide Resistance

Keep an eye out for:

• Late flushes of waterhemp, palmer, shattercane, and grasses

• Surviving weeds that may indicate resistance

• Herbicide drift symptoms (bleached, twisted leaves)

Wrapping Up: Stay Ahead by Walking Fields

You don’t have to scout every acre, but putting boots in the field now can help catch problems early and fine-tune your decisions heading into the back half of the season.

Looking for a second set of eyes or curious what we’re seeing nearby?

We’re out walking fields every day and happy to take a look.

Give Us a Shout