Paddy: blast, sheath blight, stem borer and planthoppers

In paddy, the biggest yield losses come from blast, sheath blight, stem borer and planthoppers. Most of these are made worse by excess nitrogen and dense planting, so crop management matters as much as spraying.

Doses in this guide are taken from the product labels. Always read the label and leaflet before use, respect the pre-harvest interval, and check with your nearest Biostadt retailer or agronomist for advice specific to your field.

Before transplanting

• Treat seed with Evident Flo at 3 ml per kg seed against thrips, green leafhopper and whorl maggot.
• Transplant 21–25 day old seedlings, 2–3 per hill, and leave a 30 cm alleyway every 2–3 metres. Alleyways reduce planthopper build-up and make scouting and spraying easier.
• Weed control: Rimove Plus 1500–1875 ml per hectare in transplanted rice, as per label timing.
• Split nitrogen into 3 doses; never apply heavy urea in one go.

Insect pests

Pest	Symptoms	Products
Stem borer	"Dead heart" in young crop, white empty panicles ("white ear") later	Janbaaz Gr 16.67–25 kg/ha broadcast in standing water, Dartriz 50 SP 1 kg/ha, Tremor, KlinTop
Leaf folder	Leaves folded lengthwise with white scraped streaks	Dartriz 50 SP, Fulstop – D, Ulka
Brown planthopper (BPH)	Circular patches of dried plants ("hopper burn"), insects at the base of the plant	Ultimo Super, EDAN, Wapkil

• For BPH, direct the spray at the base of the plants and drain the field for 3–4 days if possible.
• Avoid synthetic pyrethroid sprays in paddy. They kill spiders and other natural enemies and can cause BPH to flare up.

Diseases

Disease	Symptoms	Product and label dose
Blast	Spindle-shaped grey spots with brown edges on leaves; neck turns black and panicle breaks	Tagma 750 ml/ha, Bendaco 750 ml/ha, Trigger Pro 1000 ml/ha
Sheath blight	Oval, greenish-grey lesions on the sheath near the water line	Alliance 750 ml/ha, Decimer 500 ml/ha, Supermate 1000–1250 ml/ha
Brown spot, grain discolouration	Brown oval spots on leaves; dark, spotted grains	Supermate 1000–1250 ml/ha, Dolby 1500–2000 ml/ha

For neck blast, a preventive spray at boot leaf stage and a second at 50% panicle emergence is far more effective than spraying after the necks have turned black.

Spray safely

• Wear gloves, a mask, full sleeves and eye protection while mixing and spraying.
• Spray in the early morning or late evening, never against the wind or before expected rain.
• Use clean water and the full recommended water volume. Poor coverage is the most common reason a spray "does not work".
• Do not mix products unless the label allows it. If unsure, do a jar test first.
• Keep children and animals away, and never reuse empty containers. Rinse them three times, puncture them and dispose of them safely.