Which of the following is a method for controlling Thrips effectively?

Applying systemic insecticides is an effective method for controlling thrips because it allows for targeted treatment of the pests as they feed on plant sap. Systemic insecticides are absorbed by the plant and distributed throughout its tissues. This makes the entire plant toxic to thrips, providing prolonged protection against these pests that tend to hide in the flowers and leaf axils where they can be difficult to reach with contact insecticides.

When systemic insecticides are used, they can help manage thrips populations more effectively by reducing the likelihood of reinfestation and minimizing damage to the plant. This method is particularly beneficial because thrips can reproduce quickly and can cause significant damage if not controlled proactively.

In contrast, repellent sprays may not be effective in preventing thrips from infesting a plant as they do not eliminate existing populations. Additionally, applying insecticides only after significant damage has occurred can lead to worse infestations and may not protect the plant from further harm. Mechanical removal may help reduce pest numbers but is generally less effective for thrips, as they tend to be small and well-hidden in plants, making thorough removal challenging.