Question

Given below are two statements:
Statement (I): It is impossible to manage plant parasitic nematodes in protected cultivation.
Statement (II): plant-parasitic nematodes build up in the soil in the protected cultivation systems repeatedly after the application of management interventions.
In light of the above statements, choose the most appropriate answer from the options given below:

• A. Both Statement (I) and Statement (II) are true
• B. Both Statement (I) and Statement (II) are false
• C. Statement (I) is true but Statement (II) is false
• D. Statement (I) is false but Statement (II) is true

Hint:

In competitive exams, absolute terms like "impossible" are almost always scientifically incorrect.
This can help you identify Statement (I) as false, while recognizing that greenhouse pest resurgence (Statement II) is a well-known agricultural challenge.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Protected cultivation (such as greenhouses, polyhouses, and net houses) creates a modified, controlled microclimate that optimizes crop growth.
However, these favorable conditions — including stable temperatures, high relative humidity, and continuous cropping cycles — also create ideal environments for plant-parasitic nematodes to reproduce and build up in the soil.

Step 2: Detailed Explanation:
Let us analyze the two statements:
Statement (I) asserts that it is impossible to manage plant-parasitic nematodes in protected cultivation.
This is incorrect.
While nematode management in greenhouses is challenging, it is not impossible.
Growers use integrated pest management (IPM) strategies to suppress nematode populations and protect crops.
These strategies include:
- Soil pasteurization or steam sterilization.
- Soil solarization during hot summer months.
- Biofumigation using brassica cover crops.
- Applying chemical nematicides or biological control agents (such as Purpureocillium lilacinum).
- Grafting susceptible crops onto resistant rootstocks.
- Soil-less culture systems (using sterile substrates like coco-peat or rockwool).
Thus, Statement (I) is false.
Statement (II) states that plant-parasitic nematodes build up repeatedly in protected cultivation soils even after management interventions are applied.
This is correct.
Because protected systems often involve intensive monoculture of high-value, susceptible crops (like cucumber, tomato, or capsicum) without winter fallowing, any surviving nematodes can reproduce rapidly.
Even when a nematicide or soil solarization treatment reduces the nematode population below the damage threshold, the remaining individuals can quickly rebuild their population during the subsequent cropping cycle.
This rapid rebound requires growers to apply management interventions repeatedly.
Thus, Statement (II) is true.
Therefore, the correct option is (D).

Step 3: Final Answer:
Statement (I) is false because nematodes can be managed in greenhouse systems, while Statement (II) is true due to the rapid population rebound favored by continuous cropping in protected environments.