Scouting for weeds, insects, and disease

Crop scouting for weeds, insects, and diseases is a long-accepted best practice that should not be done lightly. The following information provides some basic guidelines for pest and disease crop scouting, but growers should learn the specific threats that their region and soil types are most vulnerable to. It is also important to know your limits. An analysis by a professional crop scout may quickly reap a return on investment.

Key 1: Be prepared to monitor the crop on a regular basis. Diseases and insects may seem to suddenly appear, but problems often start in small numbers. Identifying the problem early may mean spot treatment will be successful.

Key 2: Know the economic injury level (break-even point based on economic factors) for treatment and also the economic threshold (infestation level at which control becomes beneficial). Be able to apply these to individual situations.

Key 3: Know the history of your fields and consider the impact of details such as herbicides applied the previous year.

Key 4: Know the characteristics of a healthy crop, then look for signs of crop damage such as thinning, stunting, early dying, discoloration or damaged stems or leaves. Each disease and insect will cause a specific damage to a crop, so it is also important to be familiar with the symptoms of a wide variety of infestations and diseases. Understand the pests and their lifecycles.

Key 5: Analyze the weather, crop stage, weed development, and pest biology so scouting occurs at the right time.

Key 6: Walk across the field in V- or W-pattern and collect random sample. Concentrate efforts in areas where the pest, disease, or weed problem is most likely to occur. General guidelines hold that about 50 acres should be scouted at a time. Divide those acres into different zones if they have been under different management practices.

Key 7: When scouting for pests, be aware that different sampling methods are appropriate for different pests.

Key 8: Record keeping is perhaps the most important step in crop scouting. Records should include: the field location; how the samples were collected; record of data collected at each site; plant counts; row spacing; stage of crop development; and crop damage, if it is present. Remember, use clear language so you can benefit from the report year after year.

Seeds planted too deep or shallow due to poor planter adjustments will also contribute to emergence problems. If scouting reveals seeds that have swelled but not sprouted, they may have been planted too shallow. Nodal roots developing above ground also point to shallow planting. These roots are exposed to more environmental conditions and have a higher probability of encountering disease and nutrient-deficiency.

Seeds that emerge and are leafing out underground could be the result of too deep a placement. No emergence could also be the result if seeds are planted too deep. As a rule of thumb, corn should be planted about 2 inches deep. This depth will need to be adjusted depending on soil moisture.

If scouting reveals evidence of poor seed-trench closing, poorly adjusted or poorly selected closing wheels could be to blame. If the seed trench is not closed properly, all previous efforts to improve yield are jeopardized. There are a wide variety of closing products currently available on the market to prevent such misfortune. Spike closing wheels and drag chains are two popular choices.

Scouting is always a good investment

Thorough and well-executed crop scouting has a number of benefits: improved weed, insect, and disease control, an understanding of opportunities for improved equipment performance, and the development of accurate records of each fields’ history. When these benefits come together with good management, improved yields are the result.