Corn Pests And Diseases

Dried Corn
image via freepick


Pest and disease problems are the main enemy faced by the farmers, because it can result in reduced crops and even the risk of crop failure. If that happens then the losses are the thing that must be endured by them.

Here are some of the types of diseases that often attack corn plants, namely the following:

Flies seeds (Atherigona Exigua Stein)

Symptoms: The leaves change color to yellowish; Around the former bite or the affected part is experiencing decay, eventually the plant becomes wither, plant growth becomes dwarf or die. Cause: The seed flies with a grey fly color, a greenish-yellow back, and a striped, yellowish-brown belly color, a pearl white egg color, and a length of flies 3-3.5 mm. 

You need to Control:
  • Simultaneous planting and application of plant rotation will greatly help break the life cycle of saplings, especially after finishing the corn harvest.
  • Plants that are attacked by seed flies must be immediately revoked and destroyed, so that pests do not spread.
  • Cleanliness around the planting area should be maintained and always considered especially against the host plant as well as weeds.
  • Chemically controlled insecticides that can be used, among others: Dursban 20 EC, Hostathion 40 EC, Larvin 74 WP, Marshal 25 ST, Miral 26 and Promet 40 SD while dosage usage can follow the rules of use.
Caterpillar Cutters

Symptoms: The infected corn plant is usually cut in several centimeters above the surface of the soil characterized by the presence of a bite in the stem, consequently the young corn plant collapsed on the ground. Cause: Several types of Caterpillar cutters: Agrotis sp. (A. Ipsilon); Spodoptera litura, a corn-leek (Ostrinia furnacalis), and a corn-peek (Helicoverpa armigera). Control: (1) planting simultaneously on a wide area, can also be done crop rotation; (2) by finding and killing the caterpillars which are usually found in the soil; (3) before the land planted with corn, it was sprayed first with insecticide.


Corn leaf
image via freepick

Bulai Disease (Downy Mildew)
  • Cause: Mushroom Peronosclero spores maydis and P. Spores javanica and P. Spores philippinensis. Which will be rampant in the air temperature of 27 degrees C and above and humid air conditions. Symptoms: 
  • In plants aged 2-3 weeks, sharp leaves and small, stiff and stunted stem growth, yellow color, the lower side of the leaves white mushroom spores are lining.
  • In plants aged 3-5 weeks, plants are affected by experiencing impaired growth, the leaves change color and change of color is started from the base of the leaves, cob change shape and content.
  • In adult plants, there are brownish lines on the old leaves. You need to make sure that planting is done before or beginning of the rainy season, cropping pattern and crop rotation pattern, planting of superior varieties, the extraction of plants that were attacked, then destroyed.
Leaf Spotting Disease (Leaf Bligh)

Cause: Boletus Helminthosporium turcicum. Symptoms: In the leaves appear elongated and regularly colored yellow and surrounded by brown color, the spot develops and extends from the tip of the leaf to the base of the leaves, the patches again appear wet, then turn color into a yellowish-brown, then turn into dark brown. Finally, the whole leaf surface is brown. 

  • The turn of the plant should always be done to suppress the fungus's widespread.
  • Mechanical by regulating the moisture of the land so that the condition is not moist.
  • Chemical with pesticides, among others: Daconil 75 WP, Difolatan 4 F.
Rust Disease

Cause: Boletus Puccinia sorghi Schw and Puccinia Polypora Underw. Symptoms: In the adult plants that are in the old leaves some spots or stains are brownish-red like rust and there is a brownish-yellow powder, the fungus is then developed and elongated, then finally rust can be transformed into various forms.

You need to control: 
  • Regulate moisture in the planting area.
  • Planting superior varieties or varieties that are resistant to disease.
  • Doing sanitation in the area of corn planting.
  • Chemically use pesticides such as bulai disease and leaf spotting.
Swollen Burnt Disease (Corn Smut/Boil Smut)

Cause: Boletus Ustilago maydis (DC) Cda, Ustilago Zeae (SCHW) Ung, Uredo Zeae Schw, Uredo maydis DC. Symptoms: In the cob characterized by the inclusion of this fungus into the seeds so that there is swelling and secrete glands (gall), this swelling causes the wrapper pressed until the wrapper is broken and the glands out of the wrapper and spores scattered. 

You need to control:
  • Regulate the moisture area of corn planting by drying and irrigation.
  • Cut off crop parts and then burned.
  • The seed to be planted mixed with fungicide evenly until all the surface of the seed is exposed.
The Foul Disease Of Cob And Rotten Seeds

Causes: Fusarium or Gibberella's boletus include Gibberella Zeae (SCHW), Gibberella Fujikuroi (SCHW), Gibberella moniliforme. Symptoms: It can be known after opening the Cob wrapper, the seeds of pink corn or brownish-red then transformed into a ripe brown color. Control: (1) Planting corn superior varieties, done planting, regulating planting distances, treatment of seeds; (2) spraying with a fungicide after found symptoms of an attack.


Corn harvest is not all in the form of old corn/ripe physiological, depending on the purpose of harvesting. As in rice crop, the level of the fruit of corn can also be distinguished in 4 levels: Cook milk, soft cook, old ripe and cooked dry/cooked dead.

Characteristics And Harvest

The ready-to-harvest corn features are:
  • The age of Harvest is 86-96 days after planting.
  • Corn ready to be harvested with cob starts to dry which is characterized by the presence of a black coating on the seed of the institution.
  • dry, hard, and shiny beans when pressed not to trace.
  • Corn for vegetable (young corn, baby corn) is harvested before the seeds are fully charged. At that time the diameter of the new cob reached 1-2 cm. Corn to be boiled and burned, harvested when ripe milk. Signs Kelobot is still green, and if the seeds are not too harsh and will remove the white fluid. Corn for staple foods (corn rice), fodder, seeds, flour, and various other purposes are harvested if it is ripe physiological. Signs: Most of the leaves and Kelobot have been yellow. When the seeds are released there will be blackish brown color in the stem (where the seeds are attached to the cob). When the seeds are massaged with nails, do not leave the scars.

Corn harvesting
image via freepick

The way of harvesting corn that is ripe physiologic is by turning the cob following its weight or can be done by breaking the stalk of corn fruit. On the broad and flat ground is very suitable when using a defloration machine tool.

Harvest Period

Picking up corn at a less precise time, less ripe can cause quality degradation, the grain of corn becomes wrinkled even after drying will be broken, especially when separated corn with the appliance. Corn for vegetable purposes can be picked 15 to 21 days after flowering plants. Picking up corn to be consumed as boiled corn, should not wait until the seeds cook, but can be done ± 4 weeks after flowering plants or can take harvest time between harvest age of vegetable corn and the harvest age ripe corn to die.

Production Forecasts

Corn production in a country often has ups and downs. This can occur as a result of changes in the corn planting area. However, with the discovery of superior varieties as a balance of reduced land, the totality of production will not be too much change. Irrigation and fertilization is very important to get a good production. Although the potential yield is high enough, the way to get production at the optimum level is done by farmers, only give results 17 tons/ha.

After Harvesting

After the corn plucked is usually done an advanced process which is a series of related work and finally, the product is ready to be stored or marketed.


Corn is peeled at the time it is still attached to the stem or after the defloration is finished. This stripping is done to keep the moisture content inside the cob can be lowered and the moisture around the seed does not cause damage to the seeds or cause the fungus to grow. Stripping can facilitate or facilitate transportation during the drying process. For the corn to cook dead as a foodstuff, once finished harvested, the Kelobot is immediately peeled.


Drying corn can be done naturally or artificially. Traditionally corn was dried in the sun so that water content ranged from 9-11%. Usually, the clothesline takes about 7-8 days. Drying can be done on the floor, with a mat of woven bamboo or using strapped and hung.

It is made possible by a drying machine to conserve human energy, especially during the rainy season. There are various ways of artificial drying, but the same principle is to reduce the moisture content in the beans with heat drying about 38-43 degrees C so that the moisture content drops to 12-13%. The drying machine can be used at any time and can be done temperature setting according to the desired corn seed water content.


After drying until dried corn was planted. The purifier can use a hand or a corn Pemipil tool when the production amount is large enough. "Memipil " Corn is almost the same as the process of grain, that is, separating the seeds from the place of adhesive. Corn is attached to the cob, so between the seeds and the tongues needs to be separated.

Sorting And Classification

After the corn is detached from the cob, the seeds of corn must be separated from dirt or whatever is not desired, so as not to degrade the quality of corn. That needs to be separated and disposed of, among others, the remnants of the cob, small seed, seed rupture, hollow seeds, dirt during the quotation or at the time of the leverage. This action is very beneficial to avoid or suppress fungal and pest attacks while in storage. Besides, it can also improve air circulation.

For the separation of seeds that will be used as seed mainly for planting with the planter machine, usually requires uniformity of shape and size of the corn. Then this separation is very important to increase the efficiency of planting with the machine. There are various ways of cleaning or separated corn from the dirt mixture. But separation using the cleaning of rice will get good results.

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