Weed management Part 2

Описание: Principles of Weed Control
o Habits of weed plants
o Life cycle of the weed
o Susceptibilities
o Dormancy period
o Resistance to adverse conditions without losing viability
o Methods of reproduction
o Dispersal of seeds

Weeds of the horticultural crops can be controlled by
1Eradication
2 Preventive Methods
3Curative or Control measures-
(a) Biological
(b) Mechanical
(c) Cultural techniques
(d) Chemicals methods


Use of bioherbicides/ pathogens-
• Collego- colletotrichum gleosporiodes fungal spores cause stem & leaf blight.
• Biopolaris- Biopolaris sorghicola is used against johanson grass
• Biophos- it is a fermented product of streptomyces hygroscopicus.
• Devine-phytopthora palmivora fungal spores cause root rot in weeds.

Weed Controlled by
Congress grass( Parthenium hysterophorus) Beetle ( Zygrogramma bicolorata)
Lantana Camara several kinds of moths, lace bug (Teleonemia serapalora), seed fly (Ophiomyia lantanae)
Prickly pear (Opuntia vulgaris) or Nagphani weed insect (Dactlopius tomentosus)



Weed Controlled by
Water hyacinth (Eichhoronia crassipes) Mite ( Orthogalumna terebrantis)
Weevil ( Neochetina eichhorniae , N bruchi)
Water fern( Salvinia molesta) Weevil ( Cryptobagous salvinae)
S. no Time of application of herbicides
Examples
1 Pre-planting: Normally incorporated into the soil before sowing of crops in the field.
or
Pre plant incorporation(PPI) • Soil application- alachlore, fluchloraline(volatile in nature)
• Foliage application- Glyphosate, paraquat
2 Pre-emergence: prior to emergence of a specific crop or weed
Generally germinating weeds are killed by pre-emergence application.
Pre emergence- Only selective Herbicide
• For example, simazine, triazines, ureas etc.
• Pre-emergence application of Atrazine(contact & systemic action) in sugarcane, Jowar
• Alachlor in Groundnut
• Duiron or Oxadiazon in cotton.

3 Post-emergence: after emergence of crop
Foliage applied herbicides.
It is generally practiced when the crop has grown sufficiently to tolerate herbicides.
It is applied to kill weeds that appear late in the crop.
Generally, it is done about 30-40 days after sowing. • Post emergence- 2,4-D ,dalapan, propanil, diquat
• Stam F34 or MCR in paddy 3 weeks after transplanting,
• 2,4-D in Wheat after 4-8 leaf stage,
• Pendimethalin in rice after 3-5 DAT,
• Isoproturon 30 – 35 days after sowing of Wheat.
• Imazethapyr uses in soyabean, guar, groundnut, other pulses to control broad & narrow leaf weeds.

Herbicides & their trade name-
s.no Herbicides Trade name
1 2,4-D Plantguard, weedone
2 Alachlor Lasso
3 Atrazine Atratex, atratef
4 Benthiocarb Bolero, Saturn
5 Butachlor Mechate
6 Dalapan Dowfon
7 Diuron Karmex
8 Fluchloralin Basalin
9 Glyphosate Round up
10 Imazethapyr Guard
11 Isoproturon Ronak,arelon
12 Lectophan Cobra
13 Metachlor Dual
14 Metribuzin Sencor
15 Metsulfuron Escort
16 Monuron Telvar
17 Nitrofen Tok E 25
18 Oxadiazon Ronstar
19 Oxasulfuron Dynam
20 Oxyflorfen Goal
21 Paraquat Sweep, Gramoxone max
22 Pendimethalin Stomp
23 Propanil Stamp F 34
24 Sulfosulfuron Leader
Note-
• The recommendations in this article are based upon information obtained from the cited sources.
• The content of this article should not be substituted for the professional dealing with the specific crop.
• It should be used as a quick reference for information about particular crop production.