About Lesson
Control of aquatic plants
a. Biological method:
- A number of herbivorous fish and bird species are being tested as aquatic weed control agents.
|
Biological agents |
Weeds |
|
Grass carp |
Floating, emergent and submerged weeds |
|
Silver barb |
Floating, emergent and submerged weeds |
|
Tilapia |
Filamentous and planktonic algae |
|
Common carp |
Emergent and submerged weeds |
|
Silver carp |
Planktonic algae |
|
Birds |
Floating, submerged and marginal weeds |
|
Mollusk |
Periphyton |
b. Chemical method:
- Water hyacinth is controlled using 2-4 D @ 4.5-6.7 kg/ha.
- Smaller weeds like Lemna, Spirodela and Azolla are fully cleared with 0.1 kg a.i. /ha of Gramoxone.
- Emergent weeds can be controlled using 2,4 D @1.5 kg/ha mixed with 1% wetting agent.
- Submerged weeds can be controlled with CuSO4 pelleted with mud @ 35 kg/ha.
- For marginal weeds, foliar spray of sodium salt of 2,4-D @5 kg/ha or Dalapon @25-30 Kg/ha.
c. Manual and mechanical method:
- Involves physical removal of aquatic weeds manually or by power operated devices.
- Done by hand picking, uprooting, Cutting, dragging, racking or beating.
- Are labor intensive and chances of grow back of weeds is high.