Explore integrated methods and key principles of onion pest management in horticulture with these scenario-based questions. Enhance your understanding of prevention, identification, and control for healthier onion crops.
You notice small maggots feeding on the roots and bulbs of young onion plants, causing wilting; which pest is most likely responsible for this damage?
Explanation: Onion maggots are known to attack roots and bulbs, causing wilting and decay, especially in seedlings. Thrips typically feed on leaves, aphids cluster on shoots, and armyworms chew on foliage but do not target the roots and bulbs specifically.
Which cultural practice is effective for reducing onion maggot infestations before planting a new crop?
Explanation: Crop rotation helps prevent pest buildup by breaking the life cycle of the onion maggot; they rely on continuous host availability. Heavy irrigation and mulching with pine needles are less effective, while increasing plant density can sometimes worsen pest issues.
When applying insecticides to manage thrip populations in an onion field, what is an important principle to follow?
Explanation: Rotating insecticide active ingredients helps prevent thrip populations from developing resistance. Using the maximum rate is not always necessary or safe, spraying midday may reduce effectiveness, and using less spray than recommended often leads to inadequate coverage.
Which of the following is a natural enemy used to help control onion thrips in horticultural systems?
Explanation: Predatory mites are beneficial organisms that can help control onion thrips by feeding on their eggs and larvae. Root knot nematodes, onion maggots, and leafminers are not considered beneficial for thrip management and can be pests themselves.
What is a core principle of integrated pest management (IPM) when tackling multiple pests in an onion crop?
Explanation: IPM involves integrating several strategies: monitoring for pest levels, using preventive measures, and combining biological, cultural, and chemical controls as needed. Exclusive reliance on insecticides is discouraged; bulb size and total insect elimination are neither sufficient nor ecologically sound.