Fungicide Efficacy For Control Of Corn Diseases
Corn is a crucial crop to the United States, as it is an essential component of many foods, including livestock feed, ethanol, and human food products. However, corn diseases can significantly reduce crop yields, resulting in significant economic losses for farmers.
One effective way to prevent and control corn diseases is through the use of fungicides. In this article, we will explore the efficacy of fungicides in controlling common corn diseases, such as Northern Corn Leaf Blight, Gray Leaf Spot, Common Rust, and Southern Corn Leaf Blight, and discuss the best practices for their use.
Northern Corn Leaf Blight
Northern Corn Leaf Blight (NCLB) is a fungal disease that can cause significant yield losses in corn. It is caused by the fungus Exserohilum turcicum and typically occurs in cool, wet weather conditions. The disease first appears as gray-green lesions on the leaves, which quickly turn tan or brown and form an elongated cigar shape. In severe cases, the disease can cause defoliation, reducing photosynthesis and ultimately yield.
Fungicides are an effective management tool for NCLB. The most effective fungicides for controlling NCLB include Strobilurin, Triazole, and SDHI fungicides. The timing of application is critical for optimal results, and the first application should be made at the early tassel stage, followed by a second application two to three weeks later.
Gray Leaf Spot
Gray Leaf Spot (GLS) is another fungal disease that affects corn. It is caused by the fungus Cercospora zeae-maydis and thrives in warm, humid weather conditions. The disease appears as long, narrow gray-green lesions that eventually turn brown and produce a series of black dots inside the lesion.
The most effective fungicides for controlling GLS include Strobilurin, Triazole, and SDHI fungicides. The first application should be made at the early tassel stage, followed by a second application two to three weeks later. Proper timing is crucial since the fungus is known to develop resistance to fungicides if not timed correctly.
Common Rust
Common Rust is a fungal disease that affects corn and is caused by the fungus Puccinia sorghi. The disease appears as small, circular rusty-brown pustules on the leaves, which can merge and form larger patches. Severe rust infections can reduce yields by up to 40%.
The most effective fungicides for controlling Common Rust include Strobilurin and Triazole fungicides. The first application should be made at the early tassel stage, followed by a second application two to three weeks later.
Southern Corn Leaf Blight
Southern Corn Leaf Blight (SCLB) is a fungal disease caused by the fungus Bipolaris maydis. It thrives in warm, humid weather conditions and can cause significant yield losses. The disease appears as small, gray-green lesions on the leaves, which can merge to form larger lesions. In severe cases, the disease can cause defoliation, reducing photosynthesis and ultimately yield.
The most effective fungicides for controlling SCLB include Strobilurin, Triazole, and SDHI fungicides. The first application should be made at the early tassel stage, followed by a second application two to three weeks later.
Best Practices for Fungicide Use
When using fungicides, it is critical to follow label instructions carefully. Over-reliance on fungicides can lead to the development of resistance, making the fungicides ineffective over time. The following are some best practices for fungicide use:
- Rotate fungicides with different modes of action to prevent resistance.
- Apply fungicides at the recommended rates and timings.
- Avoid applying fungicides during extreme weather conditions, such as high winds or heavy rain.
- Use proper application equipment and ensure good coverage of the crop.
- Maintain proper crop nutrition and irrigation to promote healthy plant growth and reduce disease incidence.
Conclusion
Fungicides are an effective management tool for controlling corn diseases, including Northern Corn Leaf Blight, Gray Leaf Spot, Common Rust, and Southern Corn Leaf Blight. However, proper timing, application, and rotation are crucial to avoid the development of resistance and ensure optimal control. By practicing good fungicide use guidelines and monitoring disease incidence regularly, farmers can help protect their corn crops and maximize yields.