The rice leaf folder, Cnaphalocrocis medinalis (Guenee) (Lepidoptera: Pyralidae) was considered as minor pest in the past in many Asian countries. Leaffolder caterpillars fold a rice leaf around themselves and attach the leaf margins together with silk strands.
Recognize the problem
Leaf folders are caterpillars of a moth. The caterpillars roll leaves around their our bodies and feed inside the tube.
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The feeding creates a see-through whitish house on the leaf. The caterpillars are yellow to green. Heavily infested fields appear scorched and have many folded leaves.
The rice leaf folder is a commonplace pest and may also be found in all rice growth phases. The most harmful stage is all the way through tillering as this will scale back the yield of the crop.
The caterpillars can live on between rice plants by feeding on weeds across the bunds. High nitrogen fertilizer creates a whole lot of new rice plant expansion which inspires the moth to grow and multiply. The life cycle of a leaf folder is about 1.5 months (egg- 5 days, larva- 25 days, pupa- 7 days and adult moth- 10 days).
What it does
Leaffolder caterpillars fold a rice leaf around themselves and connect the leaf margins together with silk strands.
They feed inside the folded leaf creating longitudinal white and clear streaks on the blade.
Why and the place it occurs
Heavy use of fertilizer encourages speedy multiplication of the insect. High humidity and shady areas of the field, as well as the presence of grassy weeds from rice fields and surrounding borders want the improvement of the pest.
Expanded rice areas with irrigation programs, multiple rice cropping and insecticide triggered resurgences are necessary components within the insect’s abundance.
Rice leaffolders happen in all rice environments and are more plentiful all over the wet seasons. They are frequently found in shady spaces and spaces the place rice is heavily fertilized. In tropical rice areas, they’re active year-round, while in temperate countries they’re lively from May to October. The adults are nocturnal and all over the day, they keep below shade to flee predation. Moths fly short distances when disturbed.
Why is it important for rice crop management
The harm led to by leaffolders could also be important when it impacts more than half of the flag leaf and the next two youngest leaves in each and every tiller.
At vegetative segment, crops can most often get well from damage; but if leaffolders infest at reproductive segment, the damage can be economically necessary. High feeding damage at the flag leaves could cause yield loss.
Most early season insecticide use have very little financial returns. Instead, it can cause ecological disruptions in herbal biological keep watch over processes, thus improving the advance of secondary pests, akin to planthoppers.
How to identify
Check the plant for the next symptoms:
- longitudinal and transparent whitish streaks on damaged leaves
- tubular folded leaves
- leaf tips from time to time mounted to the basal part of leaf
- High rate of infested fields seem scorched with many folded leaves
To prevent the outbreak of leaf folder attack:
- Use resistant varieties.
- Contact your local agriculture office for an up-to-date list of available varieties.
- Follow rice with a different crop, or fallow period.
- Avoid ratooning.
- Flood and plow field after harvesting if possible.
- Remove grassy weeds from fields and borders.
- Reduce density of planting.
- Use balanced fertilizer rates.
- Encourage predators equivalent to spiders, parasitic wasps, predatory beetles, frogs and dragon flies
- Use thorn wooden on the leaves all through hot climate to chase bugs away
- Rice vegetation can generally recover from early damage when enough water and fertilizer are implemented
- If infestations are prime (>50%) all the way through tillering, insecticide sprays is also helpful
- Apply pesticides corresponding to alpha-cypermethrin, Abamectin 2% or Cartap hydrochloride to kill the larvae
- Note: over the top insecticide use can advertise the build-up of other crop pests such as the Brown Planthopper. Follow the producer’s suggestions on the label.
- When the usage of a pesticide, always put on protective clothing and observe the directions at the product label, corresponding to dosage, timing of utility, and pre-harvest interval.