Fodder sorghum is widely grown in India as a nutritious green fodder for cattle. It grows fast, gives good biomass, and is suitable for different climates. However, one major pest that affects its growth and yield is the stem borer. This insect damages the crop from inside the stem, reducing plant strength and fodder quality. If not controlled early, stem borer attack can cause serious losses. Farmers can protect their sorghum crop by following simple and effective management practices.
1. How Stem Borer Damages Sorghum
Stem borer larvae enter the stem and feed inside it. This interrupts the flow of nutrients and weakens the plant. Some common signs of stem borer attack are:
Dead heart in young plants
Holes on stems and leaves
Frass (powder-like waste) near the entry hole
Weak or stunted plants
Poor fodder biomass
Since the pest remains hidden inside the stem, controlling it becomes difficult once infestation becomes severe.
2. Cultural Methods of Control
Good field practices help reduce pest population naturally.
a. Timely Sowing
Early sowing of sorghum in the recommended season reduces the chance of encountering peak stem borer activity.
b. Crop Rotation
Avoid growing sorghum continuously in the same field. Rotate with legumes or other crops to break the pest cycle.
c. Removal of Stubbles
After harvest, remove and destroy leftover stalks, as stem borer larvae can survive inside them. Ploughing the field helps expose hidden pests to sunlight and predators.
d. Wider Spacing
Maintaining proper spacing improves plant health and reduces humidity, which discourages pest buildup.
e. Use Resistant Varieties
Some sorghum varieties show better tolerance to stem borer. Choosing suitable varieties helps naturally reduce damage.
3. Mechanical and Physical Control
a. Light Traps
Light traps placed in the field attract adult moths at night. This helps reduce egg-laying and lowers future infestation.
b. Collection and Destruction of Egg Masses
Regular field monitoring helps identify egg masses on the underside of leaves. Removing them by hand prevents larvae from entering stems.
c. Use of Traps with Pheromones
Pheromone traps attract male moths, reducing mating and controlling future larval population.
4. Biological Control
a. Release of Natural Enemies
Parasitic wasps and predatory insects help control stem borer larvae. Farmers can release Trichogramma cards in the field at regular intervals to reduce early-stage infestation.
b. Use of Biopesticides
Spraying neem-based products or biological insecticides like Beauveria bassiana helps control larvae before they enter the stem.
5. Chemical Control
Chemical sprays are effective mainly before the larvae bore into the stem. Once inside, sprays have limited impact.
a. Early-Stage Sprays
Spray recommended insecticides when the first signs of infestation appear—usually when small larvae are seen on leaves.
b. Proper Nozzle and Spray Coverage
Using the correct nozzle ensures that the spray reaches the whorl where larvae usually hide.
c. Avoid Late Sprays
Spraying after larvae enter the stem is not effective, so early action is important.
Conclusion
Stem borer in fodder sorghum can be controlled with a combination of cultural, mechanical, biological, and chemical methods. Early monitoring, timely sowing, clean field practices, use of traps, and preventive sprays help protect the crop. Integrated Pest Management (IPM) gives the best results and ensures healthy fodder production for livestock.
