Sorghum is a highly valued crop for its adaptability to grow in a wide range of agro-climatic conditions. However, like other crops, sorghum is also susceptible to various pests that can cause significant damage to the crop and reduce yield. One such damaging pest of sorghum is the sorghum Stem Borer. It affects sorghum crops from seedling to maturity. Warm and humid conditions are particularly favorable for the stem borers.
The life cycle of the sorghum stem borer includes four stages: egg, larva, pupa and adult. The female sorghum stem borer lays eggs on the surface of the sorghum stem. The eggs hatch into small, white larvae that burrow into the sorghum stem and feed on the inner tissue of the stem, causing damage to the plants. After feeding for several weeks, the larvae pupate inside the sorghum stem.
Type of infestation
Sorghum Stem Borer infests the stem of the sorghum plant, by feeding the inner tissue of the stem and produces dead heart symptoms. Severe infestation leads to stunted growth and yield loss.
Scientific Name: Chilo partellus
Most affected states
The sorghum stem borer is a major pest in many states of India. The states that are most affected by the pest include Maharashtra, Karnataka, Andhra Pradesh, Telangana, Madhya Pradesh, and Gujarat.
Symptoms of Sorghum Stem Borer
The sorghum stem borer infestation can be identified by the following symptoms:
- The borer attacks all parts of the sorghum plant except roots.
- Initially, larvae of sorghum stem borer feed on the upper surface of whorl leaves leaving the lower surface intact as transparent windows.
- Infested central shoot withers and produce “dead heart” symptom.
- Young larvae feed on the leaf sheath and leaf whorls causing pin holes or shot holes on the whorls of newly opened leaves.
- Older larva goes inside the stem by making a tunnel through the midrib and feed on the internal tissues.
- Bore holes can be seen on the stem, particularly near the nodes.
- As the infestation progresses, sorghum stem borer may also attack the peduncle. If both stem and peduncle are damaged, it can cause production of complete or partial chaffy panicles. Additionally, the affected peduncle may become weak and break.
The management of stem borer on sorghum plants can be achieved through an integrated approach that includes cultural, mechanical, biological and chemical measures.
- Plant resistant cultivars like E 302, E 303, IS 2205 and ICSV 700
- Plough the stubbles during winter and burn them to destroy the hibernating larvae.
- Crop rotation can be followed with non-host crops.
- Avoid using excessive amount of nitrogenous fertilizers, as this can lead to succulent growth which encourages stem borer population.
- Grow intercrops like lab lab or dolichos in the ratio of 4:1 to minimise the stem borer damage.
- Light Traps play a major role in trapping adult stem borers. Install Farmoguard Solar Light Trap in the sorghum fields at the rate of one per acre to attract and kill stem borer moths.
- Remove and destroy the infested plant parts.
- Install Tapas Yellow Sticky Trap in sorghum fields to attract adult stem borer moths. For effective trapping install 4 to 6 traps per acre.
- Encourage bio control agents such as an egg parasitoid, Trichogramma chilonis and larval parasitoids, Bracon chinensis and Apanteles flavipes to reduce stem borer population.
- Release natural predators like earwigs and spiders to control sorghum stem borers.
- Ecotin Insecticide is a neem based biological insecticide containing Azadirachtin, which when used at the rate of 0.4 – 0.7ml per liter of water with 7 to 10 days interval between each spray can effectively control stem borer in sorghum plants.
- Amruth Almax Liquid (Bio Pesticide) contains the strains of naturally occuring entomo-pathogenic fungus Beauveria bassiana, which comes in contact with the cuticle of stem borer and colonizes them. The recommended dosage is 2-3ml per liter of water.
Sorghum leaf roller can be controlled by using commercial insecticides. Some of the commonly used insecticides for controlling leaf rollers are mentioned below,
|Product Name||Technical Content||Dosage|
|Coragen Insecticide||Chlorantraniliprole 18.5% SC||0.4 ml/lit of water|
|Alika Insecticide||Thiamethoxam 12.6% + Lambda-cyhalothrin 9.5% ZC||0.5 ml/lit of water|
|Tafgor Insecticide||Dimethoate 30% EC||1.5 ml/lit of water|
|Ekalux Insecticide||Quinalphos 25 % EC||2 ml/lit of water|
|Reeva 5 Insecticide||Lambda Cyhalothrin 5 % EC||2 ml/lit of water|