Why Do Corn Leaves Have Yellow Spots? Prevention and High-Yield Growing Methods

Corn is one of the more common cash crops in our country, grown in almost every region, and during the growing period, various diseases and insect pests are often encountered, and among all the pests and diseases, yellow spots appearing on the leaves are the most common, so what is going on with yellow spots on corn leaves? How to solve it? How to grow for high yield?

Yellow spots on corn leaves are rust disease, a very common disease during corn growth; basically, in any region where corn is grown, it occurs to a greater or lesser degree, and generally it begins to develop in the middle and late stages of corn growth.

Corn rust is a climate-related infectious disease that mainly harms the leaves of corn. If not prevented and controlled in time, the corn ears will also be attacked. It is easy to judge from its appearance; everyone has seen rusty things in daily life, and the characteristics shown by corn rust are similar to rust, so it is called rust disease. It produces many pale yellow dots on the leaves, and if you touch them with your hand, you will feel raised bumps, and if you rub them with a little force, iron-rust-colored powder will scatter out. If not prevented and controlled in time, some of these yellow disease spots will later turn black, harming corn yield. Statistics show that in fields with a moderate outbreak of corn rust, yield is reduced by about 20%, and in severely affected fields it can be reduced by more than half, and of course, the most serious case is a total crop failure (Little Helper certainly does not want this situation to appear).

The causes of rust disease:

There are many causes, divided into internal and external factors. The internal factor is the variety issue; some varieties have weaker disease resistance and are easily infected by disease, and for such varieties, give them up if they should be given up and do not choose them again. As for external factors, there are quite a few, with the common one being hot and humid weather. For example, in the middle and late stages of corn growth, when there is more continuous rainy weather, the probability of corn rust occurring is very high (similar to iron rusting; when it meets water, it easily rusts. Although the principles are not the same, that is the idea, and it is enough if everyone can understand it). Another example is that when light is insufficient, the probability of rust disease also increases, and this is also easy to understand.

Solutions:

Corn rust is actually also easy to prevent and control, but since it is a disease, prevention should still be the main approach. First, when buying seeds, buy those with stronger disease resistance, then pay attention to field management, such as not making planting density too high, paying attention to the control and removal of field weeds to reduce the occurrence of pathogens, and also paying attention to weather changes. The field must not be too wet; after rain, drain water promptly and do not allow standing water. Finally, there is the issue of control agents. When prevention fails and rust disease has already occurred in the field, the commonly used agents that can be chosen include benzyl · propiconazole, tebuconazole, thifluzamide, etc. If one control application is not enough, you can apply several more at an interval of 7-10 days.

How to grow for high yield?

1. Sow at the right time

The suitable sowing period for summer corn is early to mid-June. Corn can be sown on the same day as or the day after the wheat harvest. It is advocated to harvest wheat in front and sow corn behind, achieving a “one-stop” operation of mechanical wheat harvesting with straw chopping and returning to the field, and mechanical precision sowing of corn with deep application of fertilizer. For fields where maize rough dwarf disease occurs year after year, the sowing period for summer corn can be postponed to June 10 to June 15, and severely affected fields can be sown after the 15th.

2. Sowing depth

Sowing depth depends on soil texture and soil moisture, generally 4-5 cm. If the soil is heavy or the soil water content is high, sow shallowly, with a soil cover thickness of 2-3 cm. If soil moisture is insufficient, sow deeply at 5-8 cm, with a soil cover thickness of 6-8 cm.

3. Sowing density

Achieve rational close planting according to production conditions, climate conditions, soil fertility, management level, and use. For field grain planting, the recommended planting density is 4000-4400 plants/mu, and for silage planting, the recommended planting density is 4400-4800 plants/mu. In addition to uniform-row planting at 60 cm, 65 cm, etc., you can also use wide-narrow row planting of 40 cm-80 cm or wide-row planting of more than 75 cm, which is beneficial for later field management such as fertilizing and spraying.