The vast expanses of Colorado, Kansas, Wyoming, Nebraska, and Texas are home to some of the most productive corn-growing lands in the United States. While these states continue to produce high yields, there's a microscopic menace lurking beneath the soil: nematodes.
What are Nematodes?
Nematodes, often termed as 'roundworms', are microscopic, worm-like organisms. While there are thousands of nematode species, only a few cause harm to corn plants. These parasitic nematodes can significantly reduce yields and quality, making it crucial to understand and manage them.
The Most Common Corn-Attacking Nematodes
Root-Knot Nematodes (Meloidogyne spp.)
- Prevalent in sandy soils.
- Often introduced through contaminated equipment or infested plant material.
- Proliferate in fields with a history of susceptible crops.
- Crop Rotation: Root-knot nematodes have a broad host range. However, rotating with non-hosts like certain grains or legumes can help.
- Biocontrol Agents: Beneficial fungi, such as Pochonia chlamydosporia and Paecilomyces lilacinus, can parasitize nematode eggs.
- Chemical Control: Nematicides like oxamyl can be effective but should be used judiciously due to environmental concerns.
Lesion Nematodes (Pratylenchus spp.)
- Common in a variety of soil types.
- Crop residues from previous infestations can harbor these nematodes.
- Crop Rotation: Rotate with non-host crops like barley to break their life cycle.
- Soil Fumigation: Certain fumigants can reduce nematode populations but may have broader environmental impacts.
- Resistant Varieties: Some corn varieties offer resistance or tolerance to lesion nematodes.
Stubby-Root Nematodes (Trichodorus and Paratrichodorus spp.)
- Prefer sandy or loamy soils.
- Can be spread through water runoff or infested soil transfers.
- Crop Rotation: Rotating with non-hosts can effectively reduce populations.
- Nematicides: Certain nematicides, like ethoprop, can be effective against stubby-root nematodes.
Dagger and Needle Nematodes (Xiphinema and Longidorus spp.)
- Common in deeper soil profiles.
- Often associated with orchards and vineyards due to their deeper feeding habits.
- Crop Rotation: Since they have a broader host range, selecting the right rotation crop is crucial. Non-host crops specific to your region can be effective.
- Soil Solarization: This method involves covering the soil with transparent plastic sheets during hot weather to increase soil temperature and kill nematodes.
General Causes of Nematode Infestations:
- Soil Type: Nematodes prefer certain soil types, like sandy soils, due to the ease of movement.
- Crop History: Continuously planting susceptible crops can increase nematode populations over time.
- Poor Sanitation: Using contaminated equipment or planting infested seedlings can introduce nematodes into clean fields.
- Water Source: Irrigation with contaminated water can introduce nematodes.
- Adjacent Infested Areas: Nematodes can move from infested neighboring fields, especially through water runoff.
By understanding the causes and implementing targeted treatments, growers can make informed decisions that not only control nematode populations but also promote overall soil health and crop yield. As always, consulting with local agricultural extension agents or specialists can provide region-specific guidance and solutions.
Impact on Corn Yield and Quality
Corn plants affected by nematodes often showcase stunted growth, yellowing, and nutrient deficiencies. Since the roots are the primary affected area, there's reduced water uptake, especially during dry spells, leading to wilting. Nematode damage can result in:
- Reduced Nutritional Value: Stunted growth can lead to corn with a lower nutrient profile.
- Decreased Yield: Fewer and smaller kernels mean less feed per acre.
- Elevated Aflatoxin Levels: Stressed plants are more susceptible to fungal infections, leading to increased aflatoxin levels which are harmful to cattle.
- Crop Rotation: Rotating with non-host crops like sorghum or wheat can reduce nematode populations.
- Nematode-Resistant Varieties: Research and invest in corn varieties that are resistant to nematodes.
- Biological Control: Beneficial nematodes or fungi can be introduced to combat harmful nematode species.
- Soil Testing: Regular soil tests can help monitor nematode populations and guide management decisions.
- Nematicides: Chemical treatments can be used, but they must be applied judiciously to avoid environmental harm.
The battle against nematodes is ongoing. With climate shifts and changing agricultural practices, it's essential to stay informed and proactive. Universities and agricultural research stations in our region are continuously studying nematodes and offering new insights and solutions.
Understanding the threat of nematodes is the first step in safeguarding our corn and ensuring our cattle receive the best possible feed.
To find more information and base images check out the following websites:
Acceleron, Parasites in Corn, Corn-states.com, 2017
Greg Tylka, Nematodes in Corn Production: A Growing Problem, https://crops.extension.iastate.edu/, 2/17/2007
Nematodes that feed on corn, Crop Protection Network, 3/19/2019