Question

Apple wooly aphid-resistant variety is

• A. Eastern Spy
• B. Western Spy
• C. Northern Spy
• D. Southern Spy

Hint:

Northern Spy is the progenitor variety that provided genetic resistance to the popular Malling-Merton (MM) rootstock series, protecting apple orchards from woolly aphid damage.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
The woolly apple aphid (Eriosoma lanigerum) is a serious pest of apple trees globally, attacking both the branches and roots.
Using resistant varieties and rootstocks is a highly effective, sustainable method of managing this pest.

Step 2: Detailed Explanation:
- Northern Spy is a classic American apple cultivar known for its hardiness, late-blooming nature, and distinct flavor.
Crucially, Northern Spy possesses natural, highly effective genetic resistance to the woolly apple aphid.
- When researchers and breeders at the East Malling Research Station and Merton John Innes Horticultural Institution in England wanted to develop rootstocks resistant to woolly aphids, they crossed Northern Spy with other rootstocks.
This breeding program produced the famous Malling-Merton (MM) series of apple rootstocks (e.g., MM 106, MM 111), which inherited woolly aphid resistance directly from Northern Spy.
- There are no standard commercially recognized apple varieties named Eastern Spy, Western Spy, or Southern Spy.
Thus, Northern Spy is the well-established woolly aphid-resistant cultivar.

Step 3: Final Answer:
Apple wooly aphid-resistant variety is Northern Spy.