Slender Amaranth: Spot the Spineless Kulitis in Your Rice Field
Slender amaranth is a soft, spineless broadleaf weed that grows in rainfed lowland rice fields in the Philippines. It looks a lot like its spiny cousin, but its reddish stems carry no thorns. This page shows how to tell it apart, why it matters to your palay, and how to control it before it drops seed.
What Is Slender Amaranth?
This weed belongs to the amaranth family. Farmers call it alom alom, ayang babae, halom, kilitis, kalunai, kudiapa, kulitis or uray babae, depending on where they live. The word babae in two of these names sets it apart from the spiny kind, which some call ayang lalaki. Slender amaranth grows in rainfed lowland rice fields, mostly on patches of soil that dry out between rains.
As an annual, it grows, flowers and dies within one season. It spreads only by seed, and its dense flower spikes ripen a large crop of tiny seeds. Those seeds wait in the soil and sprout when the field has no standing water. Since the stems feel soft and carry no spines, the plant comes out easily by hand, but only if you catch it before it seeds.
| Name | Slender amaranth |
|---|---|
| Scientific name | Amaranthus viridis |
| Family | Amaranthaceae |
| Weed group | Broadleaves (see the three groups) |
| Local names | Alom alom, ayang babae, halom, kilitis, kalunai, kudiapa, kulitis, uray babae |
| Life cycle | Annual |
| Spreads by | Seeds |
| Where it grows | Rainfed lowland rice fields |
How to Identify Slender Amaranth
Start with the stem. It branches a lot, stays slender and fleshy, and usually turns reddish. Run your fingers along it and you will find no spines at the leaf joints. The leaves grow one at a time along the stem, broad and oval in shape. Now look at the leaf tip: it has a small notch with a tiny bristle. Like other broadleaf weeds, the leaves have netted veins. Finally, find the green or greenish white flowers in clusters at the leaf angles and in thick spikes.
- Slender, fleshy, reddish stems that branch many times from the base.
- No spines at all where the leaves and branches join the stem.
- Broad oval leaves with a small notch and a short bristle at the tip.
- Green or greenish white flowers in clusters at the leaf angles and in dense spikes.
- Look alike tip: spiny amaranth has sharp paired spines, while this one feels smooth and safe to grab.
Why It Hurts Your Palay
Like its spiny cousin, this weed is a C4 plant. It makes good use of strong sun and heat, so it can grow quickly in open patches between the rice hills. One plant can produce 7,000 seeds, enough to fill a corner of the field with seedlings the next season. It also competes with palay for water and fertilizer, and its leaves can shade young rice.
There is a hidden cost as well. Slender amaranth is one of the plants that Meloidogyne graminicola, the nematode that causes galls on rice roots, can also live on. So while it stands on levees or fallow ground, it can help that pest survive until the next crop.
How to Control Slender Amaranth
- Pull plants by hand while they are young. The stems carry no spines, so you can grab them bare handed, but take the whole root.
- Remove plants before the flower spikes ripen, and carry them out so the tiny seeds do not fall on the soil.
- Clean levees and fallow plots between crops, since this weed can keep the rice root knot nematode alive there.
- Keep a steady flood where you can. Fewer amaranth seeds sprout under standing water than on dry, exposed soil.
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 Broadleaves
If water and weeding cannot hold slender amaranth down, choose an active ingredient that works on broadleaves 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 | 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 | Pretilachlor, Oxadiazon, Pretilachlor plus butachlor, Butachlor plus 2,4 D IBE, Pendimethalin, 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, Pendimethalin, Cyhalofop butyl plus propanil, 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, 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, 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 Slender Amaranth 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 they flower and set seed, and carry them out of the paddy instead of leaving them on the bund.
- 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 broadleaf weed in the paddy, not only this one. The weed management guide puts them in order for a whole season.
Not Sure It Is Slender Amaranth?
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 Slender Amaranth
What is slender amaranth called in the Philippines?
How do I control it in my rice field?
Why is it a problem if it has no spines?
Get Slender Amaranth out of your field
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