Cyperus distans: How to Spot and Control Slender Cyperus in Rice
Cyperus distans, or slender cyperus, is a perennial sedge weed of irrigated and rainfed lowland rice fields in the Philippines. It spreads by seed, and its clumps can live for more than one season. This page shows how to spot its slender, reddish spikelets and how to keep it out of your palay.
What Is Cyperus distans?
This damo is a sedge from the Cyperaceae family. Its English name is slender cyperus, a name that fits its thin, spreading spikelets. It has no common Filipino local name, so this page uses its scientific name, Cyperus distans. You will find it in both irrigated and rainfed lowland rice fields.
It is a perennial, so a clump can stay alive from one season to the next. It spreads by seed. Each flowering stem drops seeds into the soil, and those seeds sprout when farmers prepare the field again. Since old clumps also survive between crops, you face both old plants and new seedlings each season. That is why removing whole clumps, and not just the tops, makes the biggest difference.
| Name | Cyperus distans |
|---|---|
| English name | Slender cyperus |
| Family | Cyperaceae |
| Weed group | Sedges (see the three groups) |
| Local names | None recorded |
| Life cycle | Perennial |
| Spreads by | Seeds |
| Where it grows | Irrigated and rainfed lowland rice fields |
How to Identify Cyperus distans
Like other sedges, it has a solid, triangular stem with no nodes. The stems stand erect and feel smooth, and the three edges are easy to feel when you roll a stem between your fingers. Its leaves grow about as long as the stems. At the top, the flower head forms an open umbrella. Its slender spikelets spread outward, with a red or reddish brown color.
- Smooth, erect stems with three edges and no joints along the length.
- Leaves that grow about as long as the stems themselves.
- An open, umbrella shaped flower head at the top of each stem.
- Slender spikelets that spread outward, colored red or reddish brown.
- Clumps that survive from last season, since this sedge is a perennial.
Why It Hurts Your Palay
Like most sedges, Cyperus distans competes with palay for light, water and fertilizer. Because it is a perennial, its clumps can stay in the field from one crop to the next. So the rice you plant may meet an old, established clump instead of a weak seedling.
When it flowers, its seeds add to the weed seed bank in your soil. Those seeds can also mix with harvested palay and lower the quality of seed you keep. Thick clumps give shelter to rats and insect pests near the rice hills too.
How to Control Cyperus distans
- Dig out each clump with its base and roots instead of cutting the top, because a perennial clump can sprout again.
- Remove plants before the red spikelets ripen and fall, since this sedge spreads by seed.
- Clear clumps from bunds and field edges after harvest, so they do not survive to the next season.
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 Sedges
If water and weeding cannot hold Cyperus distans down, choose an active ingredient that works on sedges 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, Pyrazosulfuron ethyl plus pretilachlor, Imazosulfuron, Penoxsulam plus butachlor, Tefuryltrione plus triafamone, Thiobencarb plus 2,4 D IBE | Butachlor, Pretilachlor, Oxadiazon, Pretilachlor plus butachlor, Butachlor plus 2,4 D IBE, Pyrazosulfuron ethyl plus pretilachlor, Butachlor with safener |
| 6 to 10 days | Butachlor plus propanil, Cyhalofop butyl plus bispyribac sodium, Bispyribac sodium, Penoxsulam plus cyhalofop butyl, Imazosulfuron, Propyrisulfuron, Clomazone plus propanil, Thiobencarb plus propanil, Flucetosulfuron, Cyhalofop butyl plus florpyrauxifen benzyl | Butachlor plus propanil, Cyhalofop butyl plus bispyribac sodium, Bispyribac sodium, Pyribenzoxim plus cyhalofop butyl, Penoxsulam plus cyhalofop butyl, Pyrazosulfuron ethyl plus pretilachlor, 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, Bentazone, Cyhalofop butyl plus ethoxysulfuron, Propyrisulfuron, Fenoxaprop P ethyl plus ethoxysulfuron, Flucetosulfuron, Carfentrazone ethyl, Florpyrauxifen benzyl, Cyhalofop butyl plus florpyrauxifen benzyl | Cyhalofop butyl plus bispyribac sodium, Bispyribac sodium, Pyribenzoxim plus cyhalofop butyl, Penoxsulam plus cyhalofop butyl, Metamifop plus bispyribac sodium, Bentazone, Pyribenzoxim, Cyhalofop butyl plus ethoxysulfuron, Propyrisulfuron, Fenoxaprop P ethyl plus ethoxysulfuron, Flucetosulfuron, Carfentrazone ethyl, Florpyrauxifen benzyl, Cyhalofop butyl plus florpyrauxifen benzyl |
| 21 to 30 days | 2,4 D amine, 2,4 D IBE, MCPA, Metamifop plus bispyribac sodium, Bentazone, Metsulfuron methyl plus chlorimuron ethyl, Fenoxaprop P ethyl plus ethoxysulfuron, Carfentrazone ethyl | 2,4 D amine, 2,4 D IBE, Cyhalofop butyl plus bispyribac sodium, Pyribenzoxim plus cyhalofop butyl, MCPA, Metamifop plus bispyribac sodium, Bentazone, Metsulfuron methyl plus chlorimuron ethyl, Pyribenzoxim, Carfentrazone ethyl |
| 31 to 40 days | Metsulfuron methyl plus chlorimuron ethyl | 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 Cyperus distans 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.
- Prepare the land well: flood, plow, let the weed seeds sprout, then kill them when you harrow. Level the field so water covers it evenly.
- Pull escapes before their flower clusters turn brown, since one clump drops a great deal of tiny seed.
- 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 sedge weed in the paddy, not only this one. The weed management guide puts them in order for a whole season.
Not Sure It Is Cyperus distans?
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 Cyperus distans
What is the common name of Cyperus distans?
How do I control it in my rice field?
Is slender cyperus harmful to rice?
Get Cyperus distans out of your field
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