Explore the primary causes, patterns, and management of fruit drop in apple orchards with this targeted horticulture quiz. Improve your grasp of apple fruit development and factors impacting yield.
Which type of apple fruit drop typically occurs soon after petal fall and is mainly caused by failure of fertilization or poor pollination?
Explanation: June drop is the natural shedding of young fruitlets soon after blossom, usually due to inadequate fertilization or pollination. Pre-harvest drop happens closer to fruit maturity. Post-harvest drop is not a recognized type in apples. Watercore refers to a fruit disorder, not a specific timing of drop.
Which plant hormone, when present at high levels, is most associated with causing apple fruit drop?
Explanation: Ethylene is a plant hormone that promotes fruit abscission and drop in apples. Gibberellin and cytokinin are more related to growth and cell division, while abscisic acid mainly regulates stress responses and dormancy, not directly drop.
During a hot, dry summer, apple growers often experience increased fruit drop. What is the main environmental reason for this?
Explanation: Moisture stress due to drought or insufficient irrigation is a common environmental cause of increased fruit drop. Excess sunlight can cause sunscald but not directly drop. Low humidity affects transpiration but is less influential. Cold nights are not the main issue during summer drop events.
Which practice is MOST effective for reducing pre-harvest fruit drop in commercial apple orchards?
Explanation: Pre-harvest fruit drop can often be controlled by timely application of plant growth regulators such as NAA, which delay abscission. Over-fertilizing with nitrogen and delaying irrigation can worsen drop. Frequent pruning affects canopy, not directly fruit retention.
A recurring heavy fruit drop in an apple orchard is linked to leaves with pale color and weak growth. Which nutritional deficiency is MOST likely responsible?
Explanation: Nitrogen deficiency leads to pale leaves, poor vigor, and increased fruit drop. Calcium deficiency can cause disorders like bitter pit, but less fruit drop. Potassium deficiency mainly affects fruit quality. Copper toxicity is rare and not a usual cause of major fruit drop.