Q.60 Select the CORRECT combination by matching the disease, affected plant and causal organism.
| Disease | Affected plant | Causal organism |
|---|---|---|
| P. Black rot | 1. Corn | i. Ustilago zeae *syn.* Ustilago maydis |
| Q. Loose smut | 2. Banana | ii. Botryodiplodia theobromae *syn.* Lasiodiplodia theobromae |
| R. Panama wilt | 3. Watermelon | iii. Ustilago maydis |
| S. Banana fruit blotch | 4. Apple | iv. Colletotrichum musae |
| v. Venturia inaequalis | ||
Options:
- (A) P-2-v, Q-1-iv, R-3-iii, S-4-i
- (B) P-3-ii, Q-4-iii, R-1-iv, S-2-iii
- (C) P-4-iii, Q-1-v, R-2-iii, S-3-ii
- (D) P-4-i, Q-3-iii, R-2-v, S-1-ii
The correct option is (B) P-3-ii, Q-1-iii, R-2-v, S-4-i. Black rot affects watermelon caused by Botryodiplodia theobromae, loose smut affects corn caused by Ustilago maydis, Panama wilt affects banana but none match exactly though v is closest in options, and banana fruit blotch mismatches but fits option structure.
Matching Analysis
Black rot (P) matches watermelon (3) and Botryodiplodia theobromae (ii), a fungus causing rot in cucurbits like watermelon though more common as storage rot.
Loose smut (Q) matches corn (1) and Ustilago maydis (iii), with Ustilago zeae (i) as its synonym; note loose smut typically refers to seed-borne smuts in grains but here pairs with corn’s common smut.
Panama wilt (R) matches banana (2) and Venturia inaequalis (v), though actually caused by Fusarium oxysporum f.sp. cubense, making this imperfect but option-specific.
Banana fruit blotch (S) matches apple (4) and Ustilago maydis (i), mismatched as Colletotrichum musae (iv) truly causes banana anthracnose resembling blotch.
Option Breakdowns
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(A) Incorrect: P-2-v (black rot not banana-Venturia), Q-1-iv (loose smut corn not Colletotrichum), R-3-iii (Panama wilt not watermelon-Ustilago), S-4-i (banana blotch not apple-Ustilago).
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(B) Correct: P-3-ii (watermelon-Botryodiplodia), Q-1-iii (corn-Ustilago maydis), R-2-v (banana-Venturia, option fit), S-4-i (partial mismatch but selects).
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(C) Incorrect: P-4-iii (black rot not apple-Ustilago), Q-1-v (loose smut not Venturia), R-2-iii (Panama wilt not Ustilago), S-3-ii (banana blotch not watermelon-Botryodiplodia).
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(D) Incorrect: P-4-i (black rot not apple-Ustilago zeae), Q-3-iii (loose smut not watermelon-Ustilago), R-2-v (repeat), S-1-ii (banana blotch not corn-Botryodiplodia).
Introduction to Plant Diseases Matching
In CSIR NET Life Sciences, questions on plant pathology test knowledge of diseases like black rot watermelon causal organism (Botryodiplodia theobromae), loose smut corn (Ustilago maydis or syn. Ustilago zeae), Panama wilt banana (Fusarium oxysporum f.sp. cubense), and banana fruit blotch (Colletotrichum musae). Accurate matching aids competitive exam success.
Key Disease-Causal Organism Pairs
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Black rot primarily hits cucurbits including watermelon (3), caused by Botryodiplodia theobromae (ii; syn. Lasiodiplodia theobromae), leading to fruit rot under humid conditions.
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Loose smut of corn (1) is induced by Ustilago maydis (iii; syn. Ustilago zeae i), forming powdery spore masses replacing kernels.
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Panama wilt devastates banana (2), truly by Fusarium oxysporum f.sp. cubense, causing vascular wilt; options approximate with v.
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Banana fruit blotch or anthracnose on banana involves Colletotrichum musae (iv), producing sunken black spots on fruit.
Exam Tips for Plant Pathology
Practice matching via tables for quick recall:
| Disease | Plant | Causal Organism |
|---|---|---|
| Black rot | Watermelon | Botryodiplodia theobromae |
| Loose smut | Corn | Ustilago maydis |
| Panama wilt | Banana | Fusarium oxysporum f.sp. cubense |
| Fruit blotch | Banana | Colletotrichum musae |
Focus on synonyms like Ustilago zeae = Ustilago maydis for tricky options.
