What is Corn Leaf Blight?
There are two types of this plant disease – Northern and Southern corn leaf blight. In the case of Northern corn leaf blight, the one that is responsible for the disease is the Exserohilum turcicum fungus. The pathogen that carries this disease overwinters on the surface of the host plant. It also needs to stay at least six hours on the surface of the leaf before it can cause infection. It thrives in places with a moderate climate, which is about 66 to 80 degrees Fahrenheit on average.
On the other hand, the Southern corn leaf blight is because of Cochliobolus heterostrophus fungus. The carrier of this disease overwinters on the residue of corn. The fungus that carries this disease will be able to complete its life cycle in three to four days. It is a common problem in places with humid and warm climate, usually with a temperature that ranges from 70 to 90 degrees Fahrenheit.
Regardless of the type of corn leaf blight, there are some common characteristics that they share, such as the mode of transmission. The spores spread through wind or splashes of water. They can travel even through long distances in windy environments. Usually, the infection starts from the bottom part of the plant and travels all the way up.
Identifying Corn Leaf Blight’s Damage
As the name implies, corn is the main host for this disease, although there are specific cultivars of corn that are more susceptible compared to others. There are also strains of pathogens that can affect sudangrass and Johnson grass.
The following are some of the most common signs that corn leaf blights are affecting your plants or crops:
- With the name of the disease, it is obvious that the leaves will show the most obvious symptoms. Lesions will appear on the leaves, with size ranging from three to 15 centimeters. They are green or gray in color. To add, because it inhibits photosynthetic activity, the leaves can turn dry. The host plants can also suffer from loss of leaves.
- While the fungus attacks the leaves, other parts of the plant will also show visible signs of damage, especially the cob and ear of the corn. It will rot, which is primarily because of the inability to receive the nutrients that are critical for its survival.
Results of Infestation
Both Northern and Southern corn leaf blight can cause serious damages to corn. Early development of the disease will deter the growth of the plant. The appearance of lesions will inhibit photosynthesis. Therefore, this will deprive the plants of the nutrients that it needs. The damages will not only be cosmetic in nature, but can also be economic. Commercial growers can suffer from huge losses as a result of the infestation. The crop yield will be lesser than normal, which is the reason why profits will be lesser. The fungal disease can bring more damages to the host plant if the infection occurs earlier in the growing season.
How to Get rid of Corn Leaf Blights
Natural and Organic Solutions
Below are some of the most effective methods to prevent and treat corn leaf blights, helping to minimize economic losses that can result from their infestation:
- Growing plants that can resist this disease is one of the best ways to spare yourself from headache. There are plants with a moderate resistance, which will delay the onset of the disease and will give you time to treat it before it spreads. In some cases, when you purchase seeds, the label will indicate its resistance to diseases. It is also good to plant non-host crops to prevent frustration from the disease.
- The pathogens carrying corn leaf blights may overwinter, which is why crop rotation will also offer a promising solution. This will prevent the possibility that the fungi in the corn residues from the previous season will transfer to new plantings. One to two years of crop rotation is a good way to manage the infestation.
- Tillage is another thing that will help, which is especially effective as a preventive measure. This will clear the surface of corn debris that can be potential sources of disease. In line with this, sanitation of the garden will also be a big help.
- Monitoring is also important to control corn leaf blights. With this, you need to detect the problem as early as possible. Watch out for the symptoms of the disease. If you are sure that it is corn leaf blight, deal with the problem as soon as possible. Uprooting will help to prevent the disease from spreading to the other plants.
- See to it as well that the condition of the soil is at its best. This will make the plants healthier and will increase their defense against common diseases. To add, keep it dry by having proper irrigation. If the soil is moist all the time, it will be more susceptible to the spread of the disease.
Chemical treatment is one of the most common solutions to the problem, especially amongst commercial growers. However, it is important to do this with caution. These chemicals can be harsh for the environment and for humans. Pay attention to the instructions from the manufacturer. Professional application may also be necessary.
Among others, foliar fungicides are some of the most effective for corn leaf blights. To be specific, some of the products that you might want to use include Stratego and Quadris. The application of foliar fungicide is necessary if the disease is quickly spreading or if it exceeds economic thresholds.