Ludwigia decurrens: How to Spot and Control It in Rice Fields
Ludwigia decurrens is an upright, yellow flowered broadleaf weed that farmers call Kahoy kahoy, malapako or tina tina. It grows in both irrigated and rainfed lowland rice fields in the Philippines. This page shows you how to spot it by its winged stems, and how to control it before it sheds its seed.
What Is Ludwigia decurrens?
In English, Ludwigia decurrens is called wingleaf primrose willow. It belongs to the evening primrose family, Onagraceae. In the bukid, farmers use the names Kahoy kahoy, malapako and tina tina. But these same names also cover its close relatives, so look at the stem to tell them apart. Being a broadleaf weed, it is not a grass or a sedge.
You can find it in both irrigated and rainfed lowland rice fields. As an annual, each plant finishes its life in one season. Seed is its only way to spread. The seeds form inside angled, narrowly winged pods, and they fall onto the soil when the pods open. Then they wait for the next cropping and sprout along with the palay.
| Name | Ludwigia decurrens |
|---|---|
| English name | Wingleaf primrose willow |
| Family | Onagraceae |
| Weed group | Broadleaves (see the three groups) |
| Local names | Kahoy kahoy, malapako, tina tina |
| Life cycle | Annual |
| Spreads by | Seeds |
| Where it grows | Irrigated and rainfed lowland rice fields |
How to Identify Ludwigia decurrens
Check the stem first. It stands upright, feels smooth, and has four thin wings running along its length. That winged stem is your best clue. The leaves sit almost flat on the stem, with hardly any stalk, and are narrow and pointed with smooth edges. Like other broadleaf weeds, its leaves have netted veins, unlike the parallel veins of grasses and sedges. The yellow flowers have four big petals with sharp tips, and the pods are sharply angled or narrowly winged.
- Upright, smooth stems with four thin wings running down their whole length.
- Narrow, lance shaped leaves sitting almost flat on the stem, with smooth edges.
- Yellow flowers with four big petals that each end in a sharp tip.
- Seed pods that are sharply angled or carry narrow wings, much like the stem.
- Look alike tip: its kahoy kahoy cousins have angled or ridged stems, not winged ones.
Why It Hurts Your Palay
Here in the Philippines, there is no reported scientific proof yet that Ludwigia decurrens lowers rice yield. But studies in other countries found that it could cut rice yield by 33 percent when 4 to 8 plants grow in each square meter. So even a modest stand deserves your attention.
Other studies found that this weed is allelopathic to rice. That means it releases substances that can hold back the growth of rice plants nearby. Some variants have also become resistant to a certain herbicide. Because of this, do not count on a single product to clear it. Hand weeding and good water care still matter.
How to Control Ludwigia decurrens
- Pull plants by hand while they are young, before the yellow flowers turn into winged seed pods.
- Since it spreads only by seed, never let a plant flower on the bunds or field edges, where seed can wash into the paddy.
- Do not depend on one herbicide year after year, because some variants have already become resistant to a certain herbicide.
- Bring pulled plants with flowers or pods out of the field, since pods left on the mud can still open and drop seed.
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 Ludwigia decurrens 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 |
Studies in other countries found that some variants of this weed have developed resistance to a certain herbicide, so rotate products and do not rely on one.
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 Ludwigia decurrens 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 Ludwigia decurrens?
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 Ludwigia decurrens
What is Ludwigia decurrens called in Tagalog and other local names?
How do I control this weed in my rice field?
Is this weed harmful to my palay?
Get Ludwigia decurrens out of your field
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