Chamber Bitter in Rice Fields: How to Spot and Control It
Chamber bitter is a small, slender broadleaf weed with reddish stems that farmers call apoy apoyan, payog or turutalikod. It comes up in rainfed lowland rice fields, mostly on soil that is not under water. This page shows you how to spot it, how to tell it apart from its look alike, and how to control it in your palay.
What Is Chamber Bitter?
Chamber bitter, or Phyllanthus urinaria, belongs to the spurge family, Euphorbiaceae. It carries many local names: apoy apoyan, ibaiba an, lurulaioan, minuhminuh, payog, sursampalok, tabi, takum takum, talindanon and turutalikod. Some of these names, like sursampalok and turutalikod, also refer to its close cousin, Phyllanthus debilis. So when a neighbor names it, ask about the red stems.
It grows in rainfed lowland rice fields. Like its cousin, it is an annual that lives for one season and spreads only by seed. The seeds ripen in small capsules under the leaves and then fall to the soil. A few plants left to mature can fill your field with seedlings in the next crop. So weeding before the capsules ripen saves you work later.
| Name | Chamber bitter |
|---|---|
| Scientific name | Phyllanthus urinaria |
| Family | Euphorbiaceae |
| Weed group | Broadleaves (see the three groups) |
| Local names | Apoy apoyan, ibaiba an, lurulaioan, minuhminuh, payog, sursampalok, tabi, takum takum, talindanon, turutalikod |
| Life cycle | Annual |
| Spreads by | Seeds |
| Where it grows | Rainfed lowland rice fields |
How to Identify Chamber Bitter
This weed stands upright, slender and branched, with no hairs. First, check the color: its stems and branches look reddish. Its many small, oblong leaves line up in neat rows along each branch, on very short stalks. Like other broadleaves, its leaves are flat with netted veins, unlike grasses and sedges. Under the branches, the flowers sit with no stalk or a very short one, and the capsules feel rough.
- Small, slender, upright plants with reddish stems and branches between rice hills.
- Rows of small oblong leaves along each branch, each leaf on a very short stalk.
- Tiny flowers sitting close to the branch, with no stalk or a very short one.
- Small round seed capsules that feel rough, lined up under the leaves.
- Look alike tip: Phyllanthus debilis is bigger, lacks the red stems, and has stalked flowers and smooth capsules.
Why It Hurts Your Palay
This little weed still takes light, water and fertilizer that your palay needs. When many plants come up together, they crowd the young rice before its leaves close over the rows.
The bigger problem is the seed. It lives only one season, but each plant that escapes weeding drops seed into the soil. In rainfed fields, those seeds sprout when the soil turns moist again. So every plant you miss this season means more weeding work next season.
How to Control Chamber Bitter
- Pull plants while they are young, before the capsules under the leaves ripen and fall to the soil.
- Keep a shallow layer of water in the field when rain allows, since standing water keeps many land weeds like this from sprouting.
- Weed the bunds and field edges as well, because plants there set seed unnoticed and reseed the field.
- Bag pulled plants that already carry capsules and take them out, so ripe seed does not drop back onto the 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 chamber bitter 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 Chamber Bitter 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 Chamber Bitter?
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 Chamber Bitter
What is chamber bitter called in Tagalog and other dialects?
How do I get rid of this weed in my rice field?
How do I tell chamber bitter from niruri?
Get Chamber Bitter out of your field
With Libre + Anee, read the whole guide: how to tell it from your crop, and what to do and spray at every age of your crop.
The account is free, no credit card.
