Model Answer
0 min readIntroduction
Citrus fruits, vital contributors to India’s agricultural economy and nutritional security, are increasingly threatened by a range of insect pests. These pests cause significant yield losses and economic hardship for farmers. The citrus industry faces challenges from sucking pests, borers, and fruit-damaging insects. Among these, the citrus psylla, *Diaphorina citri*, has emerged as a particularly problematic pest globally, including in India. Its rapid reproduction and ability to transmit diseases necessitate effective management strategies, moving beyond traditional approaches. Understanding its biology and implementing integrated pest management (IPM) techniques is paramount for sustainable citrus production.
Major Insect Pests of Citrus
Citrus cultivation is plagued by several insect pests. Some of the major ones include:
- Citrus Leafminer (CLM): Causes leaf damage and reduces photosynthesis.
- Citrus Aphids: Suck sap, leading to stunted growth and honeydew production.
- Citrus Thrips: Damage fruits and leaves, affecting quality and marketability.
- Orange Spider Mite: Causes bronzing of leaves and reduces vigor.
- Citrus Trunk Borer: Destroys the bark and vascular tissue, leading to tree death.
- Fruit Flies: Damage fruits, rendering them unmarketable.
Citrus Psylla: Diaphorina citri
Biology and Life Cycle
The citrus psylla is a small, white-winged insect that feeds on the sap of citrus leaves and stems. Females lay eggs on the underside of citrus leaves, usually near the midrib. Eggs hatch into nymphs that undergo four instars before becoming adults. The entire life cycle takes approximately 28-35 days, depending on temperature. They are highly prolific, with a single female laying several hundred eggs during her lifetime.
Damage Caused
Citrus psylla causes several types of damage:
- Leaf Yellowing and Stunting: Feeding by nymphs and adults causes leaves to turn yellow and stunt growth.
- Stem Swelling: Psylla feeding can cause characteristic stem swellings, which distort the tree's shape and reduce fruit production.
- Honeydew Production: Psylla excrete honeydew, a sugary substance that attracts sooty mold, which reduces photosynthesis and affects fruit quality.
- Disease Transmission: Citrus psylla is a vector for “Cadang Jungus” disease in some regions, a devastating viral disease of citrus.
Management Strategies
Effective management of citrus psylla requires an integrated approach:
Conventional Methods
| Method | Description | Limitations |
|---|---|---|
| Insecticides | Application of systemic and contact insecticides. | Development of resistance, environmental concerns, impact on beneficial insects. |
| Oil Sprays | Application of horticultural oils to smother and kill psylla. | Can be phytotoxic under certain conditions, requires careful application. |
Integrated Pest Management (IPM)
IPM strategies offer a more sustainable approach:
- Biological Control: Encouraging natural enemies like parasitic wasps (e.g., *Anagyrus loecki*) and predatory insects. Releasing commercially available parasitoids can also be effective.
- Cultural Practices: Pruning to improve air circulation, removing infected leaves, and proper fertilization can reduce psylla populations.
- Monitoring: Regular monitoring of leaf and stem swellings to determine infestation levels and guide management decisions. Sticky traps can also be used.
- Pheromone Traps: Using pheromone traps to disrupt mating and reduce psylla populations.
- Neem Oil: Application of neem oil acts as a repellent and disrupts insect growth.
The National Horticulture Board (NHB) provides support for citrus cultivation, including pest and disease management, under various schemes. Farmers are encouraged to adopt IPM practices to minimize reliance on chemical pesticides.
Case Study: Kerala’s Citrus Psylla Management Program
Kerala, a major citrus-growing state in India, has implemented a comprehensive citrus psylla management program. This program emphasizes biological control through the release of *Anagyrus loecki* and promotes farmer awareness regarding IPM practices. The program has resulted in reduced insecticide usage and improved citrus yields, demonstrating the effectiveness of an integrated approach.
Conclusion
Citrus psylla poses a significant threat to citrus production, demanding a proactive and sustainable management approach. While conventional methods offer immediate control, the long-term solution lies in embracing integrated pest management strategies that prioritize biological control, cultural practices, and farmer education. Continuous monitoring, research into resistant varieties, and promoting beneficial insects are crucial for safeguarding the citrus industry and ensuring food security. A shift towards ecologically sound practices is essential for the future viability of citrus cultivation in India.
Answer Length
This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.