Thrips Control Challenge Quiz

Assess your understanding of thrips pest management strategies in horticultural chilli production with scenario-based questions covering identification, monitoring, cultural, chemical, and biological control methods.

1. Identifying Thrips Damage in Chilli

   Which of the following symptoms most accurately indicates thrips infestation on chilli plants in a horticultural setting?

   1. Silvery streaks and distorted leaves
   2. Large holes chewed on fruit
   3. Black circular leaf spots
   4. Yellowing due to root rot

   Explanation: Silvery streaks and distorted, curling leaves are typical of thrips feeding, as thrips scrape the plant surface and suck sap. Black circular spots are usually caused by fungal diseases, not insects. Chewed holes are more typical of caterpillars or beetles. Root rot results in general yellowing, not the specific foliar damage described.

2. Monitoring Approaches

   In a chilli field, which method is most effective for regularly monitoring thrips population levels?

   1. Pheromone traps for moths
   2. Blue or yellow sticky traps
   3. Applying neem oil sprays
   4. Water-flooding of the soil

   Explanation: Sticky traps are specifically used to capture flying thrips and help monitor their population trends. Water-flooding targets soil pests instead, not monitoring. Pheromone traps target moths, not thrips. Neem sprays are for management, not for monitoring pest levels.

3. Cultural Control Practices

   Which cultural practice can help reduce thrips infestation in chilli crops?

   1. Increasing irrigation frequency
   2. Spraying broad-spectrum fungicides weekly
   3. Deep ploughing after harvest
   4. Removing weeds and plant debris

   Explanation: Weeds and plant debris provide shelter and breeding sites for thrips, so removing them can lower pest levels. Weekly fungicides do not target thrips. Increasing irrigation does not specifically suppress thrips. Deep ploughing helps manage soil pests but is less effective for thrips, which mostly live on the crop.

4. Chemical Control Selection

   For chemical control of thrips in chilli, what should be considered to avoid resistance development?

   1. Rotating insecticides with different modes of action
   2. Using the same insecticide throughout the season
   3. Spraying chemical controls before any pests appear
   4. Doubling the recommended dose when thrips are seen

   Explanation: Rotating insecticides with different action modes helps prevent thrips from developing resistance. Using the same product promotes resistance. Early, unnecessary sprays contribute to pest adaptation and environmental harm. Doubling doses is unsafe and can increase non-target damage.

5. Biological Control Agents

   Which biological control agent is most commonly released in chilli fields to manage thrips populations?

   1. Predatory mites like Amblyseius spp.
   2. Ladybird beetles for aphids
   3. Parasitic wasps for caterpillar eggs
   4. Nematodes for rootworms

   Explanation: Predatory mites such as Amblyseius spp. are effective natural enemies of thrips and are used for their management. Ladybird beetles target aphids, nematodes are released for soil pests, and parasitic wasps typically target caterpillars or their eggs rather than thrips.