Gooseweed: How to Spot and Control It in Rice Fields
Gooseweed is an upright broadleaf weed with soft, hollow stems and a green, finger like flower spike. Farmers call it silisilihan, mais mais or burat aso. It grows in both irrigated and rainfed lowland rice fields across the Philippines. This page shows you how to spot it early and how to control it before it cuts your harvest.
What Is Gooseweed?
Gooseweed, or Sphenoclea zeylanica, belongs to the family Sphenocleaceae. Its local names include balabalanob, burat aso, mais mais and silisilihan. The names mais mais and silisilihan compare it to corn and chili. You will find it in irrigated and rainfed lowland rice fields, and it does well in wet, muddy soil.
This weed is an annual, so it lives for one season and spreads only by seed. Each green flower spike carries many small flowers, and each one leaves seed behind. Since the plant thrives in flooded fields, water alone will not stop it. That is why you need to weed it out early, before the spikes mature and drop seed into the mud.
| Name | Gooseweed |
|---|---|
| Scientific name | Sphenoclea zeylanica |
| Family | Sphenocleaceae |
| Weed group | Broadleaves (see the three groups) |
| Local names | Balabalanob, burat aso, mais mais, silisilihan |
| Life cycle | Annual |
| Spreads by | Seeds |
| Where it grows | Irrigated and rainfed lowland rice fields |
How to Identify Gooseweed
This weed stands upright and branches out between the rice hills. Squeeze a stem and you will feel that it is soft and hollow. As a broadleaf, its leaves are flat with netted veins, unlike grasses and sedges. They are narrow, oblong to lance shaped, pointed at the tip and set on short stalks. The best clue is the flower spike. It looks like a small green cylinder, with white to greenish flowers.
- Upright, branched plants with soft, hollow stems standing among the rice.
- Narrow, pointed leaves on short stalks, oblong to lance shaped.
- Green, cylinder shaped flower spikes at the top, like a small corn cob.
- Tiny white to greenish flowers set along the green spike.
- Plants that survive a 2,4 D spray, which may point to a resistant variant.
Why It Hurts Your Palay
Gooseweed can cut rice yield by 45 percent. It grows tall and leafy in flooded fields, so it competes with your palay for light, water and fertilizer. A thick stand can also shade young rice between the rows.
There is another problem. Some variants of this weed resist 2,4 D, a common broadleaf herbicide. So spraying the same product season after season may leave resistant plants alive. Those survivors then drop seed and fill your field with more of the same.
This weed has a natural enemy. A fungus called Alternaria alternata f. sp. sphenocleae infects it. When researchers inoculated plants with 10 spores per milliliter, the plants showed blight and wilting after 24 hours. By 6 days, all the plants had died. So this fungus may become a natural control in the future. For now, ask your municipal agriculturist before you try any fungus based method.
How to Control Gooseweed
- Hand weed early, before the green spikes ripen, because each spike can drop many seeds into the mud.
- Do not count on flooding to stop it. This weed thrives in standing water, so keep weeding even in a flooded field.
- If plants survive a 2,4 D spray, pull them by hand before they seed, so resistant plants do not spread.
- Change your control method across seasons instead of relying on one product every time.
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 gooseweed 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 |
Some variants of gooseweed resist 2,4 D, according to reports, so this herbicide may not kill every plant in your field.
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 Gooseweed 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 Gooseweed?
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 Gooseweed
What is gooseweed called in Tagalog?
How do I control silisilihan in my rice field?
Is this weed really harmful to my palay?
Get Gooseweed 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.
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