Spraying process for rice in the tillering and tillering stages

Tiering — growing the field is the stage that determines the number of flowers and seeds, but it is also easy to encounter brown planthoppers, leaf rollers, rice blast, brown spot, and stem borers. Instructions for spraying according to threshold, protecting natural enemies and avoiding excess nitrogen.

Summary: The tillering — panicle stage is when rice builds productivity: the number of effective shoots, panicle leaves and future panicles. This is also the period when many pests begin to exceed the threshold, such as brown planthoppers, leaf rollers, rice blast, brown spot, and stem borers. This article guides the spraying process according to IPM: visiting the field, counting the population, choosing the right crop-protection product, and spraying at the right location.

Applies to: Rice from 40 days after sowing to before flowering, including full tillering, tillering and tillering.
Duration: Monitor every 5-7 days; When there is adverse weather, check every 2-3 days.
Difficulty level: Medium. It is necessary to distinguish pests and diseases according to the layer of leaves, roots and sheaths.
Estimated additional costs: 300-700 thousand VND per acre if spraying is required; Spraying at the right threshold helps reduce the number of spraying times.

Objective of this stage

From tillering to growing paddy fields, rice plants need:

Keep the number of effective shoots.
Protects functional leaves.
Don't let the hoppers burn the fields.
Do not let rice blast or leaf spot destroy the leaves.
Don't let stem borers cause white flowers later.

Fungicide spraying at this stage must be balanced: enough to protect productivity, but not destroy natural enemies and not create drug resistance.

Objects to be checked

Brown planthopper

Living at the rice base.
Sucking plastic and transmitting viral diseases.
You need to count leafhoppers on the clump, don't look at the color of the field from afar.
Spray low at the root when the threshold is exceeded.

Leaf roller

Roll leaves and eat parenchyma.
The damage is more severe when the rice is grown in paddy fields and the leaves are affected.
It is necessary to open the rolled leaves to count the living larvae.

Rice blast and stripe

Blast blast is often related to cold weather, dew, and excess nitrogen.
Stripe spots thrive in dense, moist, heavily sown fields.
Do not add nitrogen while the disease is developing.

Stem borers

Need to check the nest.
Pay attention to the pre-flowering stage, from light flowering to the end of flowering.
Spray when eggs are about to hatch or larvae have just hatched.

Checklist before spraying

[ ] Is the rice tillering or cultivating?
[ ] Which pest/disease is the main one?
[ ] Is the processing threshold exceeded?
[ ] Does this period of spraying affect natural enemies?
[ ] Do I need to adjust the water or fertilizer first?
[ ] Which group does the drug you used last time belong to?
[ ] Is the weather suitable for spraying?

If you don't know the main target, you should not mix multiple drugs to "surround".

Decision-making process

When you see dense green rice, leaf diseases increase

Step 1: check the amount of nitrogen applied.

Step 2: stop applying nitrogen if the disease is occurring.

Step 3: keep water properly, avoid fields being too wet.

Step 4: spray the right target if the disease rate exceeds the threshold.

When you see leaf rolling worms

Step 1: open the rolled leaves to see if there are still larvae.

Step 2: count the number of larvae per square meter.

Step 3: if the threshold is exceeded, choose the correct drug group and spray while the worm is still small.

Step 4: do not spray if the leaf roll is an old lesion.

When you see brown planthoppers

Step 1: mark the rice base, count leafhoppers.

Step 2: determine the age of the leafhopper.

Step 3: if the threshold is exceeded, spray low at the root.

Step 4: monitor the plant for symptoms of yellow dwarfism/leaf curling.

Correct spraying technique

Spray in the cool afternoon or morning when the dew has dried.
Do not spray before rain.
Use enough water.
For leafhoppers: spray low, near the base.
For leaf diseases: evenly cover the leaf layer that needs protection.
For leaf rollers: spray when the worms are still young.
For stem borers: spray right when the eggs are about to hatch.

Each object has a different position. One-size-fits-all spraying is often ineffective.

Protect natural enemies

At this stage, the field usually has many natural enemies:

Spider catching prey.
Ladybug.
Parasite wasps.
The bugs eat their prey.

Should be avoided:

Spray broad-spectrum crop-protection products when pest populations are low.
Mix many crop-protection products at the same time.
Use a group of active ingredients repeatedly.
Spray the entire field when the worms only concentrate in clusters.

Keeping natural enemies helps reduce leafhopper and leaf roller pressure at the end of the season.

What to do after spraying

Check again after 3-7 days depending on the subject.
Record the password before and after spraying.
Do not repeat spraying if the field is already below the threshold.
Adjust the stool/water if that is the cause of the outbreak.
Change the active ingredient group if you have to spray next time.

Spraying is only part of the treatment. If the field still has excess nitrogen, thick sowing, and high humidity, the disease will easily return.

Monitor periodically

[ ] Brown planthoppers at the base: population and age of planthoppers.
[ ] Leaf roller: larvae still alive in leaf rollers.
[ ] Blast: diamond-shaped marks on leaves.
[ ] Stripes: lesions from the sheath/lower layer.
[ ] Stem borers: nest eggs on leaves.
[ ] Nitrogen amount and leaf color.
[ ] Forecast rain, dew, wind.

Regular tracking helps spray less but more accurately.

Common mistakes

Spray on a fixed schedule: does not rely on numbers, easily wastes treatment.

Fertilize with nitrogen and then spray for disease: excess nitrogen causes leaf diseases to return quickly.

Spraying hoppers on top: hoppers are at the base, low efficiency.

Do not open the rolled leaves to count worms: it is easy to spray on old damage.

Using the same active ingredient continuously: pests and diseases become less sensitive, making it difficult to manage later.

Take notes

Rice stage.
Main pests/diseases.
Number or disease rate.
Active ingredients and date of spraying.
Feces/water during that week.
Results after 3-7 days.

Taking notes helps distinguish fields that need to be sprayed from fields that only need to adjust water distribution.

References

*Spraying process for rice in the tillering and tillering stages* — Hainong technical document.
*IPM Integrated Pest Management Guide* — Hainong technical document.
*Rice IPM Handbook* — FAO Vietnam.