FROM PLANT PESTS TO CROP HEALTH: THE IMPORTANCE OF EARLY SEASON CORN SCOUTING

Early season crop scouting plays a vital role in proactive crop management. Catching an issue early allows for early intervention measures, helps optimize crop performance, minimizes potential losses, and maximizes overall yield potential. 

Before building a crop scouting plan, you’ll need a few important tools. 

• Digging utensils: To dig up plants and check roots and plant depth.  
• Extension booklets: Local state extension offices have weed, disease, and insect guides available. 
• Electronics: To take pictures and/or notes, utilize a calculator, and communicate with  your agronomist. 
• Notepad and pen or pencil: To keep track of notes, measurements, and observations.  

Once a farmer has all the right tools, they’ll need to creating a crop scouting plan: 

• Determine scouting objectives and goals: Identify potential issues—like weeds, diseases, pests, and nutrient deficiencies—that may arise during specific growth phases. What a grower will monitor might also depend on their desired outcomes, like prevention (if they’ve dealt with the same issue in previous seasons) or yield optimization. 
• Identify scouting areas: Divide fields into management scouting areas based on the  following factors: crop type, acreage, soil type, or previous pest and disease issues.
• Choose a scouting method: This could be visual observation, soil sampling, aerial drones, scouting apps and software, and disease scoring. 
• Establish scouting procedures: Walk through each scouting area to observe crop condition (height, population, leaf color), identify any pest or disease issues, spot weed competition, or take note of other relevant factors. Accurately record all observations, including location and severity. 

With a comprehensive crop scouting plan, timely detection, effective management, and optimized crop performance are all possible throughout the growing season.

ASSESS EMERGENCE AND STAND ESTABLISHMENT 

Early crop scouting can also give growers a bird’s-eye view over any potential establishment issues, like:

• Stand density and uniformity: A stand’s success will depend on its density (number of plants per area) and uniformity (evenness of plant spacing). Low plant density or uneven spacing can indicate planting issues (such as poor seed quality, planting depth, or seeding rate) or indicate unfavorable soil conditions. 
• Gaps and skips: Identify any areas with poor or no emergence. These can result from factors such as seed depth, seed quality, soil crusting, and  insect or disease damage. 
• Replant considerations: If significant emergence issues are obvious, consider a replant. This decision will depend on the severity of  the issue, calendar date, yield potential of the existing crop, and costs associated with a  replant. Consult with your AgriGold agronomist for guidance on making replant decisions. 

WEEDS 

Specific weeds found during early crop scouting can vary by region, crop type, and environmental conditions. These can include: 

PIGWEED 

What it is: Many species exist, including the common redroot pigweed (summer annual weeds). They have broad, egg-shaped leaves and can grow rapidly, stealing nutrients from crops. 

Size: Older, mature pigweeds can grow to 10 feet, but traditionally are around 2-3 feet. 

When it will emerge: Pigweeds begin to emerge in late spring to early summertime but can continue to emerge in late summer. 

FOXTAIL 

What it is: Several species of foxtail grasses, such as green and yellow foxtail, are problematic summer annual weeds. They have dense, cylindrical seed heads. 

Size: Foxtail grasses can grow from 1 to 3 feet tall. 

When it will emerge: Foxtail species begin to emerge in early April but will continue in  May. 

RAGWEED

What it is: The ragweed species are summer annual weeds with deeply lobed leaves and a rough texture. Ragweed is known for producing an abundance of pollen, which takes moisture and nutrients away from corn and soybeans and reduces yields. 

Size: Common ragweed will grow up to six feet tall. 

When it will emerge: Ragweed will begin to emerge in April and will continue throughout May. 

PESTS 

Pests can significantly impact crops during their early growth states, so it’s crucial to spot them early. Here are some common pests to watch out for during the early season. 

BLACK CUTWORM  

What to look for: One of the first signs of black cutworms is leaf-feeding on crops that have  begun to emerge.  

WHITE GRUBS  

What to look for: White grub damage tends to occur in rows where soybeans fail to emerge.  By digging up existing soybean plants in the affected area(s), look in the root zone for white  grubs. 

WIREWORMS  

What to look for: Wireworms feed at the base of corn and soybean seed to get to the base of the stem where growth occurs. Wireworm damage may include skips and gaps between rows and/or wilting plants.  

CORN FLEA BEETLES  

What to look for: Evidence of corn flea beetles will look like stripping of the top layer of a corn plant. This will lead to gray to brown lines on the surface. Damage is more likely to occur if environmental conditions aren’t ideal during the growth period. 

NUTRIENT DEFICIENCIES

Nutrient deficiencies in corn and soybeans will show up with specific visual symptoms. Here are some common deficiencies and the accompanying signs to look out for: 

NITROGEN (N) 

• Pale or yellowing leaves, starting from the bottom of the plant and moving upward, usually in a V pattern. 
• Reduced growth and stunted plants. 
• To reduce further loss, a sidedress or Y drop application may be necessary.

PHOSPHORUS (P) 

• Purplish or reddish discoloration on leaves (on the older ones first). 
• Poor root development and stunted plants. 
• Take soil samples in each area of phosphorus deficiency to create a plan to increase available P for future crops. 

MAGNESIUM (MG) 

• Areas between leaf veins turn yellow while the veins remain green. 
• Leaf curling and marginal leaf necrosis. 
• Reduced photosynthesis and poor plant growth. 

• Dolomitic limestone contains a high concentration of calcium carbonate (CaCO3) and magnesium carbonate (MgCO3). When applied, it gradually releases calcium and magnesium ions, adjusting soil pH and improving nutrient availability. 

DISEASES 

Catching a disease early during scouting can empower timely management strategies. Here are some common diseases (and their signs) to watch for: 

PHYTOPHTHORA  

• Seedlings fail to emerge or collapse shortly after emergence. 
• Rot in the seeds, roots, or lower stem portions. 
• Wilting and yellowing of leaves, starting from the base of the plant. 

GRAY LEAF SPOT  

• Small dot with yellow on the outer edge. 
• Lesions start to develop on lower leaves and progress upwards. 
• Lesions may increase in size and elongate, often reaching several inches in length. 

NORTHERN CORN LEAF BLIGHT 

• Initially, small, elongated lesions appear as gray-green or tan spots on the leaves. 
• Lesions may have wavy or parallel margins 
• As the disease progresses, lesions expand.

EARLY CROP SCOUTING IS A NECESSITY

Strong yields don’t start at harvest time. They start much earlier in the season — and early crop scouting is a huge part of that timeline. Early crop scouting can help: 

• Identify weeds, pests, nutrient deficiencies, and diseases in their early stages: This increases the chances of effective intervention and management, and reduces further damage to the crop. 
• Be proactive: With early scouting comes earlier preventative strategies. This could look like earlier herbicide, fungicide, or sidedress applications, which can help optimize crop health and yield. 
• Save growers money: By catching issues early, growers can reduce the need for more extensive (and more costly) interventions later in the season. 

Don’t let Mother Nature throw a curveball during the growing season: get a head start on scouting. Our agronomists are just a phone call away to answer any questions about early scouting, mitigation tactics, or other strategies to maximize yields.