Hedyotis biflora: How to Spot and Control It in Your Palay
Hedyotis biflora is a small, slender broadleaf weed. Farmers know it as pisak, dalumbang or palarapdap. It grows in irrigated and rainfed lowland rice fields in the Philippines. This page shows you how to spot it among your palay and how it takes from your crop. It also shows how to control it before it sets seed.
What Is Hedyotis biflora?
Hedyotis biflora is a small annual herb from the coffee family, Rubiaceae. Its stems are thin and branched, and the plant either stands upright or spreads out low. Farmers in different places call it dalumbang, kaddok na kalinga, palarapdap, pisak or pisek. Because it stays small and slender, it is easy to miss between the rice hills.
You will find this damo in both irrigated and rainfed lowland rice fields. Its life lasts one season. Within one crop it sprouts, flowers, sets seed and dies. Seed is its only way to spread. The tiny seeds fall around the mother plant and wait in the soil for the next crop. So a patch you ignore this season can come back thicker next time.
| Name | Hedyotis biflora |
|---|---|
| Family | Rubiaceae |
| Weed group | Broadleaves (see the three groups) |
| Local names | Dalumbang, kaddok na kalinga, palarapdap, pisak, pisek |
| Life cycle | Annual |
| Spreads by | Seeds |
| Where it grows | Irrigated and rainfed lowland rice fields |
How to Identify Hedyotis biflora
Look low between the rice hills for a small herb with thin, branching stems. Some plants stand upright, while others sprawl. The leaves are oval to oblong, set in pairs, and sit on very short stalks. Like other broadleaf weeds, the leaves are wide with netted veins, unlike grasses and sedges. When it blooms, its tiny flowers come in small umbrella like clusters of 2 to 8. A similar weed, Hedyotis corymbosa, also grows in rice, but its leaves are much narrower and taper to a point.
- A small herb with thin, branched stems, standing upright or spreading low between rice hills.
- Oval to oblong leaves on very short stalks, set in pairs along the stem.
- Thin stems that branch many times, giving the plant a light, airy look.
- Tiny flowers grouped in small umbrella like clusters of 2 to 8.
- Look alike tip: Hedyotis corymbosa shares its local names but has long, narrow leaves.
Why It Hurts Your Palay
This weed is small, but it still competes with your palay. It takes water, nutrients and fertilizer from the same soil your rice roots use. When many plants come up together, they fill the open spaces between young rice hills. Young rice feels this the most, because it is still building roots and tillers.
Since it is an annual that spreads by seed, every plant that flowers adds to the seed supply in your bukid. That is why it returns season after season. Its seeds can also end up mixed with the harvested palay. Thick weedy patches can give insects a place to hide near the crop as well.
How to Control Hedyotis biflora
- Weed early and often. Small, slender plants are easy to miss, so walk the paddy carefully while the rice is still young.
- Pull it before the tiny flower clusters form seed. Once seeds drop, they wait in the soil for the next crop.
- Keep good water in the paddy where you can. Small seeded annual weeds sprout more easily on moist, exposed soil than under standing water.
- Clean the bunds and field edges as well, since plants there can 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 Broadleaves
If water and weeding cannot hold Hedyotis biflora 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 Hedyotis biflora 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 Hedyotis biflora?
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 Hedyotis biflora
What is Hedyotis biflora called in local languages?
How do I control pisak in my rice field?
Is such a small weed really worth pulling?
Get Hedyotis biflora out of your field
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