Stem borer is one of the most harmful pests in pigeon pea (arhar) cultivation. The pest affects the crop mainly during the vegetative and early flowering stages. The larvae bore into the stem, feed inside, and block the flow of nutrients. This causes wilting of branches, poor plant growth, fewer pods, and reduced yield. In some fields, stem borer can destroy a large portion of the crop if not controlled in time. Farmers can manage this pest effectively by combining cultural, mechanical, biological, and chemical methods.
1. Identify early symptoms
Early detection is important to prevent serious damage.
Common symptoms of stem borer attack include:
Yellowing and drying of top shoots
Holes on the stem where larvae enter
Withered branches
Reduced growth and fewer flowers
Pulling out a damaged branch often shows a caterpillar inside the stem.
2. Select disease- and pest-tolerant varieties
Using improved and resistant varieties helps reduce stem borer attack. Many new arhar varieties have better tolerance to pests. Choosing suitable varieties for your region is a simple step that gives long-term protection.
3. Follow proper crop rotation
Avoid growing pigeon pea in the same field every year.
Rotate with crops like maize, sorghum, green gram, or black gram.
Crop rotation reduces the buildup of pests in the soil and breaks their life cycle.
4. Timely sowing and proper spacing
Early sowing at the start of monsoon helps avoid peak pest activity.
Maintain adequate spacing between rows (60–90 cm) for good air flow and sunlight. Thickly planted fields create humidity, which supports pest growth.
5. Mechanical control
Farmers can remove and destroy infested branches in the early stages.
This helps prevent the larvae from completing their life cycle.
Do not throw damaged branches in the field—burn or bury them properly.
6. Use pheromone traps
Pheromone traps are very effective in monitoring and reducing stem borer population.
Install 10–12 traps per acre in the field to attract and trap adult moths.
This reduces egg-laying and lowers future infestation.
7. Neem-based sprays
Neem products are highly useful against stem borer, especially in the early larval stage.
Use:
5% Neem Seed Kernel Extract (NSKE)
0.5% Neem oil with soap solution
Neem reduces the feeding ability of larvae and helps protect the plant without harming natural predators.
8. Encourage natural enemies
Beneficial insects like Trichogramma, ladybird beetles, and parasitic wasps help suppress stem borer naturally.
Avoid unnecessary use of strong pesticides, as they kill these helpful insects.
9. Chemical control (only when needed)
When infestation becomes severe, recommended insecticides may be applied.
Spray during evening hours when larvae are active.
Ensure proper coverage, especially on the main stem and lower branches.
Rotate chemicals to avoid resistance.
10. Keep the field clean
Remove weeds and leftover plant material.
Pests often survive in crop residues and attack new crops the next season.
Deep ploughing after harvest exposes larvae and pupae to the sun, reducing their survival.
Conclusion
Controlling stem borer in pigeon pea requires early monitoring and a mix of good farming practices. By using resistant varieties, maintaining field hygiene, applying neem-based sprays, installing pheromone traps, and using chemicals only when necessary, farmers can effectively manage this pest. Timely action ensures healthier plants, better flowering, and higher pigeon pea yields.
