Question

Match the LIST-I with LIST-II and choose the correct answer from the options given below: \[ \begin{array}{|l|l|} \hline \textbf{LIST I (Common powdery mildews)} & \textbf{LIST II (Causal organism)} \\ \hline A.\ \text{Powdery mildews of barley} & I.\ \text{Cercosphaera leucotricha} \\ B.\ \text{Powdery mildews of peas} & II.\ \text{Uncinula necator} \\ C.\ \text{Powdery mildews of grape vines} & III.\ \text{Erysiphe polygoni} \\ D.\ \text{Powdery mildews of apple} & IV.\ \text{Erysiphe graminis var. hordei} \\ \hline \end{array} \]

• A. A - I, B - II, C - III, D - IV
• B. A - I, B - III, C - II, D - IV
• C. A - I, B - II, C - IV, D - III
• D. A - IV, B - III, C - II, D - I

Hint:

Mnemonic: {Barley–hordei}, {Pea–polygoni}, {Grape–Uncinula}, {Apple–leucotricha}. Match host cues to species epithets.

Answer 1

The Correct Option is D

Step 1: Recall host–pathogen pairs for common powdery mildews.
Barley powdery mildew is classically associated with Erysiphe graminis var. hordei, a host-specific form that attacks cereals.
Pea powdery mildew is commonly attributed to Erysiphe polygoni in standard horticulture texts for legumes.
Grape powdery mildew is caused by Uncinula necator, the well-known agent in vineyards worldwide.
Apple powdery mildew is caused by the organism historically recorded as Sphaerotheca or Podosphaera leucotricha; in the given list it appears as Cercosphaera leucotricha and represents the same disease entity for matching.
Step 2: Perform the matching.
A (barley) → IV (Erysiphe graminis var. hordei).
B (peas) → III (Erysiphe polygoni).
C (grape vines) → II (Uncinula necator).
D (apple) → I (Cercosphaera leucotricha).
Step 3: Conclusion.
Therefore the correct mapping is A - IV, B - III, C - II, D - I, which corresponds to option (4).