The Pink stem borer (Sesamia inferens) is a destructive pest of maize (corn) plants that cause significant damage to the plant’s stems. The larvae of the pink stem borer feed on the inner tissues of the stem, which can cause the plant to wilt and ultimately lead to its death. Maize, known as corn, is a cereal grain that is one of the world’s most widely cultivated and consumed crops.
It’s a staple food in many countries. It is used for various purposes, including human consumption, livestock feed, and industrial products such as biofuels and starch. Maize is a warm-season crop that requires a long growing season, plenty of sunlight, and warm temperatures. The high yields and versatility of maize make it a valuable crop for farmers and an important contributor to food security in many regions of the world.
Pink Stem Borer management in Maize
The life cycle of Pink Stem Borer
The life cycle of the pink stem borer in maize is accurate. The pink stem borer can complete its life cycle in 40-70 days, and there can be 4-6 generations per year, depending on the climate conditions. The eggs are laid in clusters of leaves and are pale yellowish-green in color.
The larvae feed on the tissues of the stem after hatching, causing significant damage to the plant. The fully-grown caterpillar is cylindrical, with a red-brown head and a 20-25 mm length. The pupation takes place inside the stem, and each stage of the life cycle, including the egg, larval, and pupal stages, lasts 7-10 days, 20-30 days, and 8-10 days, respectively.
Identification of Pink Stem Borer in the Maize field
- The eggs are creamy white and spherical, laid in batches between the leaf sheaths and stem of the plant.
- The larva is pinkish brown with a reddish brown head.
- The pupa is brown and obtect, pupating inside the stem.
- The adult is a straw-colored moth with forewings that have three black spots and a faint brown mid-stripe and white hindwings.
Damage symptoms of Pink Stem Borer in Maize field
The larvae of the pink stem borer are significant pests of maize, causing damage by feeding on all parts of the plant except the roots. When they hatch, they feed on the epidermal layer of the leaf sheath, leading to gummy oozing and water-soaked lesions.
Some larvae migrate to neighboring leaf sheaths, while others penetrate the stem, causing damage in the form of oblong holes in unfolded leaves, drying of the growing point, formation of dead hearts in young plants, and circular or “S”-shaped tunnels filled with excreta inside the stem. Severe infestations can cause stunted plant growth, breakage of the stem, and damage to immature cobs, silks, and tassels. The larvae can cause significant harm to the maize crop and result in reduced yields.
Cultural control of Pink Stem Borer
- Uprooting and destroying infected maize plants can help reduce the population of the pink stem borer and prevent it from spreading to healthy plants.
- Collecting and destroying the stubbles after harvesting the crop can also help reduce the number of places where the pink stem borer can lay its eggs.
- Crop rotation can also be an effective management strategy as it can help reduce the buildup of the pink stem borer population in a specific area. By planting different crops in different seasons, you can break the pest’s life cycle and reduce the damage it causes.
Chemical control of Pink Stem Borer
The application of BHC (benzene hexachloride) and DDT (dichlorodiphenyltrichloroethane) at 0.1% in spray or 1% in dust, as well as the spray of fenthion, fenitrothion, quinalphos, phosphamidon, and granules of lindane, can be effective in controlling the pink stem borer pest in maize.