Question

List the major pests and diseases of rice and discuss shoot borer's damage and management.

Hint:

Remember: Rice shoot borer causes deadhearts in vegetative stage and whiteheads in reproductive stage. Integrated management combining resistant varieties, cultural practices, biological control, and need-based chemical application is most effective.

Answer 1

Part 1: Major Pests and Diseases of Rice
Step 1: Understanding the Question
This part asks for a list of the most common pests (insects) and diseases that affect the rice crop.
Step 2: Detailed Explanation
Major Pests of Rice:

Stem Borer (Shoot Borer): Yellow stem borer is the most common.

Leaf Folder: Larvae fold the leaves and feed from inside.

Brown Plant Hopper (BPH): Sucks sap from the base of the plant, causing "hopper burn".

Gundhi Bug (Earhead Bug): Sucks the milky sap from developing grains, causing them to be chaffy.

Gall Midge: Maggots feed inside the tillers, causing a silvery shoot called "onion leaf".

Major Diseases of Rice:

Blast: A fungal disease causing spindle-shaped spots on leaves and neck rot.

Bacterial Leaf Blight (BLB): A bacterial disease causing yellowing and drying of leaves from the tip downwards.

Sheath Blight: A fungal disease causing lesions on the leaf sheath near the water line.

Tungro Virus: A viral disease transmitted by green leafhoppers, causing stunting and yellowing of plants.

Part 2: Shoot Borer's Damage and Management
Step 1: Understanding the Question
This part requires a detailed discussion of the damage caused by the rice shoot borer (stem borer) and how to manage it.
Step 2: Detailed Explanation
Damage Caused by Shoot Borer:
The larva of the stem borer moth bores into the rice stem to feed. The damage symptoms differ based on the crop stage:

At the Vegetative Stage (before flowering): The larva cuts the central shoot from inside, causing it to dry up. This is known as a "dead heart".

At the Reproductive Stage (after flowering): The larva cuts the stalk of the panicle (the flowering head). This prevents grain formation, and the entire panicle turns white and empty. This is known as a "white earhead".

Management of Shoot Borer:
An Integrated Pest Management (IPM) approach is recommended:

Cultural Methods: Use resistant varieties, plow the field after harvest to destroy stubble containing larvae, and collect and destroy egg masses.

Biological Methods: Encourage natural enemies like spiders and dragonflies. Release egg parasitoids like Trichogramma japonicum.

Mechanical Methods: Use pheromone traps to monitor and mass-trap the male moths.

Chemical Methods: Apply insecticides like cartap hydrochloride or fipronil granules in the nursery or main field only when the pest population crosses the Economic Threshold Level (ETL).

Step 3: Final Answer
Major pests of rice include stem borer and BPH, while major diseases include blast and BLB. The rice shoot borer causes "dead hearts" and "white earheads". Its management involves an integrated approach using cultural, biological, and chemical methods.