Cyperus compressus: How to Identify and Control This Annual Sedge
Cyperus compressus, the annual sedge, forms dense tufts in irrigated and rainfed lowland rice fields in the Philippines. Farmers call it gisai kalabaw or tuhog dalag. It grows from seed and lives for only one season. This page shows you how to spot its flat, greenish spikelets and how to control it before it drops seed.
What Is Cyperus compressus?
This damo is a sedge from the Cyperaceae family. Its English name is annual sedge, while farmers in the provinces know it as gisai kalabaw or tuhog dalag. Cyperus compressus grows in both irrigated and rainfed lowland rice fields.
As its English name says, it is an annual. It sprouts, flowers and dies within one season. It spreads by seed only, so every plant you let flower adds new seeds to the soil. Those seeds wait for the next land preparation, then sprout with the new crop. That is why early weeding pays off with this sedge. If you clear it before it flowers, you cut off the next generation at the source. A few minutes of hand weeding now can save you hours later.
| Name | Cyperus compressus |
|---|---|
| English name | Annual sedge |
| Family | Cyperaceae |
| Weed group | Sedges (see the three groups) |
| Local names | Gisai kalabaw, tuhog dalag |
| Life cycle | Annual |
| Spreads by | Seeds |
| Where it grows | Irrigated and rainfed lowland rice fields |
How to Identify Cyperus compressus
Like all sedges, it has a solid, three sided stem with no nodes, unlike the round, hollow stem of rice. The stems are smooth and green, and many of them grow in a dense tuft from one base. Its leaves stay shorter than the stems. At the top, the flower head looks simple and open. Each spike holds 3 to 10 flat, greenish spikelets crowded together like fingers.
- Dense tufts of smooth, green stems rising together from a single base.
- Leaves that stay shorter than the flowering stems, so the heads stand above them.
- An open, simple flower head instead of a tight, round ball.
- Spikes with 3 to 10 crowded spikelets spread out like the fingers of a hand.
- Greenish spikelets that look very flat, as if pressed between the pages of a book.
Why It Hurts Your Palay
Like other sedges, Cyperus compressus competes with your palay for light, water and fertilizer. Its dense tufts take up room between the rice hills, and its roots draw on the same nutrients. If it sprouts together with the crop, young rice plants feel that pressure the most.
Because it is an annual, it relies on seed to come back. Every plant left to flower adds seed to the soil, so the problem grows each season. Its seeds can also end up in harvested palay and lower the quality of seed you keep. Thick patches give shelter to insect pests near the rice hills, too.
How to Control Cyperus compressus
- Pull the tufts by hand while they are young and before the flat spikelets ripen, since it spreads only by seed.
- Level the field well and keep water over the soil after planting, so its seeds have fewer dry spots to sprout in.
- Weed the bunds and dry corners too, so no plant there drops seed back into the paddy.
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 compressus 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 compressus 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 compressus?
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 compressus
What do Filipino farmers call Cyperus compressus?
How do I control it in my rice field?
Is annual sedge harmful to palay?
Get Cyperus compressus out of your field
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