Question

For the management of Meloidogyne enterolobii in Guava, which of the following is most effective?
(A) Chemical pesticides
(B) Biological control agents
(C) Improvement of soil organic carbon
(D) Use of clean planting material in nematode-free soil. Choose the correct answer from the options given below:

• A. (A), (C) and (D) only.
• B. (A), (B) and (D) only.
• C. (A), (B), (C) and (D).
• D. (B), (C) and (D) only.

Hint:

No single control method is fully effective against aggressive nematodes like M. enterolobii. Always select the "Integrated Nematode Management" option that combines preventive, biological, and chemical methods.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
The guava root-knot nematode (Meloidogyne enterolobii) is an aggressive and destructive plant-parasitic nematode.
It causes severe galling on root systems, leaf yellowing, wilting, and significant yield loss in guava orchards.
Because it can overcome host resistance in many crops, managing M. enterolobii requires an Integrated Nematode Management (INM) approach that combines multiple control tactics.

Step 2: Detailed Explanation:
An effective integrated management strategy for M. enterolobii includes the following components:
(A) Chemical pesticides:
Applying approved chemical nematicides (such as fluopyram or carbofuran) around the root zone helps reduce high nematode populations in infested orchards, providing quick relief to the trees.
(B) Biological control agents:
Using biocontrol agents, such as egg-parasitic fungi (Purpureocillium lilacinum) and antagonistic bacteria (Pseudomonas fluorescens or Bacillus species), helps suppress nematode populations over the long term without causing chemical buildup in the soil.
(C) Improvement of soil organic carbon:
Adding organic amendments like neem cake, castor cake, or well-decomposed farmyard manure increases soil organic carbon.
This stimulates beneficial soil microbes and predatory nematodes, which naturally suppress root-knot nematodes while improving plant vigor.
(D) Clean planting material:
Preventive measures are essential.
Using certified, nematode-free guava saplings grown in sterile, soil-less media prevents the introduction of this aggressive pathogen into clean fields.
Because a combination of all four practices (A, B, C, D) is the most effective way to manage this pest, they should be used together in an integrated program.

Step 3: Final Answer:
Managing M. enterolobii requires an integrated approach utilizing all of the listed methods.
This corresponds to Option 3.