Southern Cutgrass in Rice Fields: How to Spot and Remove It
Southern cutgrass is a creeping perennial grass weed of irrigated and rainfed lowland rice fields in the Philippines. Its leaves carry tiny backward spines that feel rough and can scratch your skin. This page shows how to spot it, how it hurts your palay and how to keep it in check, season after season.
What Is Southern Cutgrass?
Southern cutgrass (Leersia hexandra) belongs to the grass family, the same family as palay. Farmers call it amgid or barit. It grows in both irrigated and rainfed lowland rice fields, and it handles wet, flooded ground well. Its stems rise at an angle or stand almost upright, and they root wherever a joint touches wet soil.
This weed is a perennial, so it does not die after one season. It spreads by seed and also by its rootstocks, the stems that run under the soil and store food. When you plow or pull it, broken pieces of rootstock stay in the mud. Each piece can grow into a new plant. That is why a small patch keeps growing if you only cut the tops.
| Name | Southern cutgrass |
|---|---|
| Scientific name | Leersia hexandra |
| Family | Poaceae (Graminae) |
| Weed group | Grasses (see the three groups) |
| Local names | Amgid, barit |
| Life cycle | Perennial |
| Spreads by | Seeds and rootstocks |
| Where it grows | Irrigated and rainfed lowland rice fields |
How to Identify Southern Cutgrass
Like other grasses, it has round, hollow stems with clear joints, or nodes. The stems rise at an angle or stand almost straight, and they root at the nodes. The leaves are long and narrow, tapering to a fine point. Now run your fingers along the midrib on the back of a leaf. You will feel tiny spines that point backward and catch your skin. The ligule is long, thin and rounded. The seed head has slender branches and oblong spikelets.
- Stems lean up at an angle or stand almost straight, rooting at the joints.
- Leaves are long and narrow, and each one ends in a fine, tapering point.
- Tiny backward pointing spines line the back of the midrib and catch your skin.
- The ligule is long and thin, with a rounded tip.
- Slender seed head branches stand nearly upright and carry oblong spikelets.
- Patches come back in the same spots season after season from old rootstocks.
Why It Hurts Your Palay
As a perennial, this grass does not wait for a new season to start. Old rootstocks are often still alive when you plant, so it starts taking water, light and fertilizer from your palay right away. Its rooting stems also knit into thick mats that crowd young rice hills.
It costs you labor too. Pulling the tops does little, because the rootstocks send up new shoots. So weeding by hand takes longer, and the rough leaves scratch the hands that pull them. Besides that, thick patches can give rice pests shelter between crops. Its seeds may also end up mixed with your harvest.
How to Control Southern Cutgrass
- Dig out each clump with its rootstocks during land preparation. Any piece you leave in the mud can sprout again.
- After plowing, rake the broken rootstock pieces out of the paddy and dry them on high ground, not on the bund.
- Flooding alone will not stop it, because this grass grows well in wet ground. Rely on digging and careful land preparation instead.
- Wear gloves and long sleeves when you weed it, since the tiny spines on its leaves can cut your skin.
What to Do at Each Age of Your Rice
- 0 to 5 days: keep the soil saturated. Use a pre emergence herbicide only if the field had many weeds last season.
- 6 to 10 days: hand weed in transplanted rice. In direct seeded rice, this is the window for an early post emergence spray.
- 11 to 20 days: keep water in the field, weed by hand or with a rotary weeder, and let Azolla and the Altica beetle help. Spray only if those fail.
- 21 to 30 days: top up the water and keep weeding. Spray only if weeding fails.
- 31 to 40 days (transplanted rice): hand weed. A spray this late is only a rescue.
- After any post emergence spray, bring the water back within 1 to 3 days at 3 to 5 cm and hold it for 4 to 5 days. Keep young rice above it.
Active Ingredients That Work on Grasses
If water and weeding cannot hold southern cutgrass down, choose an active ingredient that works on grasses at the age of your rice. Each active ingredient in it is in a herbicide registered in the Philippines for rice. Shop by the ingredient on the label, never by the brand. If your field also has other kinds of weeds, the weed control helper in anee.io finds the ingredients that cover all of them.
| Rice age (days after planting) | Transplanted rice (lipat tanim) | Direct seeded rice (sabog tanim) |
|---|---|---|
| 0 to 5 days | Butachlor, Pretilachlor, Oxadiazon, Butachlor plus 2,4 D IBE, Pendimethalin, Pyrazosulfuron ethyl plus pretilachlor, Clomazone, Penoxsulam plus butachlor, Tefuryltrione plus triafamone, Tetflupyrolimet, Thiobencarb plus 2,4 D IBE | Butachlor, Pretilachlor, Oxadiazon, Pretilachlor plus butachlor, Butachlor plus 2,4 D IBE, Pendimethalin, Pyrazosulfuron ethyl plus pretilachlor, Butachlor with safener, Clomazone, Tetflupyrolimet |
| 6 to 10 days | Butachlor plus propanil, Cyhalofop butyl plus bispyribac sodium, Bispyribac sodium, Penoxsulam plus cyhalofop butyl, Pendimethalin, Cyhalofop butyl plus propanil, Propyrisulfuron, Clomazone plus propanil, Thiobencarb plus propanil, Flucetosulfuron, Cyhalofop butyl plus florpyrauxifen benzyl | Butachlor plus propanil, Cyhalofop butyl plus bispyribac sodium, Bispyribac sodium, Cyhalofop butyl, Metamifop, Pyribenzoxim plus cyhalofop butyl, Penoxsulam plus cyhalofop butyl, Cyhalofop butyl plus propanil, Pyrazosulfuron ethyl plus pretilachlor, Pendimethalin, Propyrisulfuron, Clomazone plus propanil, Thiobencarb plus propanil, Pretilachlor plus pyribenzoxim, Penoxsulam, Flucetosulfuron, Cyhalofop butyl plus florpyrauxifen benzyl |
| 11 to 20 days | Cyhalofop butyl plus bispyribac sodium, Bispyribac sodium, Pyribenzoxim plus cyhalofop butyl, Penoxsulam plus cyhalofop butyl, Metamifop plus bispyribac sodium, Cyhalofop butyl plus ethoxysulfuron, Propyrisulfuron, Fenoxaprop P ethyl plus ethoxysulfuron, Flucetosulfuron, Florpyrauxifen benzyl, Cyhalofop butyl plus florpyrauxifen benzyl, Profoxydim | Cyhalofop butyl plus bispyribac sodium, Bispyribac sodium, Cyhalofop butyl, Metamifop, Pyribenzoxim plus cyhalofop butyl, Penoxsulam plus cyhalofop butyl, Metamifop plus bispyribac sodium, Pyribenzoxim, Cyhalofop butyl plus ethoxysulfuron, Propyrisulfuron, Fenoxaprop P ethyl plus ethoxysulfuron, Flucetosulfuron, Florpyrauxifen benzyl, Cyhalofop butyl plus florpyrauxifen benzyl, Profoxydim |
| 21 to 30 days | Metamifop plus bispyribac sodium, Fenoxaprop P ethyl plus ethoxysulfuron | Cyhalofop butyl plus bispyribac sodium, Metamifop, Pyribenzoxim plus cyhalofop butyl, Metamifop plus bispyribac sodium, Pyribenzoxim |
| 31 to 40 days | No herbicide listed at this age. Hand weed and keep the water up. | Not listed for direct seeded rice |
Spray Safely
Use only herbicides registered with the Fertilizer and Pesticide Authority, and follow the label on the pack: the rate, the timing, the water and the protective clothing. Switch herbicide groups between seasons so the weeds do not learn to survive them. Our guide to herbicides for rice explains the groups.
Keep Southern Cutgrass Out Next Season
- Plant clean, certified seed. Weed seeds mixed into the punla are the easiest way in.
- Keep the seedbed, the canals and the bunds free of weeds, so seed does not wash or blow into the paddy.
- Plow and harrow well, and rake out the runners, roots or pieces you turn up. A small piece left in wet soil can grow a new plant.
- Pull escapes before the seed heads open, and clean the thresher and harvester before they enter the field.
- Keep the field clean after harvest and through the fallow, so fewer seeds build up in the soil for next season.
These steps work for every grass weed in the paddy, not only this one. The weed management guide puts them in order for a whole season.
Not Sure It Is Southern Cutgrass?
Take a clear photo of the leaf, the stem and the flower or seed head, then ask Anee, the smart farm technician in anee.io, in Tagalog or English. Anee tells you which weed it most likely is, its group, and what to do at the age of your rice. You can also put the weeding days on your cropping calendar, so the team knows when to go in.
anee.io keeps your weeding, spraying and water on one calendar, and Anee answers when a plant looks wrong.
- Weeding days on the season calendar
- Photos and notes for every lot
- Anee, the smart farm technician, in Tagalog or English
Questions Farmers Ask About Southern Cutgrass
What do farmers call southern cutgrass locally?
How do I get rid of it in my rice field?
Why does southern cutgrass keep coming back?
Get Southern Cutgrass out of your field
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