Weed Important Study Point
Subject:- Weed Science
Weeds Important Study Point
Weed Classification
A. Based on leaves
| 1.Broad leave weeds | |
| Goose grass, Field bind weed, Amaranthus, Wild jute, Carrot grass, Bull head, and Sweet clover. | |
| 2.Narrow leave weeds | |
| Bermunda grass, Java grass/nut grass, Kansh, canary grass, Jonson gras and wild oat. |
B. On the basis of Cotyledons
| 1.Monocots Weeds | |
| Weeds of Gramanie family are generally come under his group. | |
| Ex.- Bermunda grass, Jonson grass, Nut grass, Wild onion, Canary grass and Wild oat. | |
| 2.Dicots weeds | |
| Seeds of his weed can be easily divided symmetrical two parts. | |
| Ex.- Goose foot, Field bind weed, Red chick weed and Sweet clover. |
C. On the basis of Season
| 1.Kharif weeds | ||
| They appear with the onset of monsoon (June, July) and complete their life cycle when rainy season is over (Oct or Nov). | ||
| Ex. Wild rice, amaranthus, wild jute, garden spurge, spider weed, and Striga. | ||
| 2.Rabi weeds | ||
| They complete their life cycle during winter season (Oct/Nov to Feb). | ||
| ex- Canary grass, field bind weed, wild onion, lorethus, goose weed, | ||
| 3.Zaid weeds | ||
| They complete their life cycle during summer season ( Feb to May). | ||
| Ex. Mexican poppy, pig weed |
D. Basis of Life cycle
| 1.Annual |
| 1. Kharif- Eleusine, Echinochloa, Celosia, Cyperus |
| 2. Rabi- Argemone. Euphorbia, Solanum, Phalaris, Chengrodiam |
| 2.Biennial |
| Dacus carota, wild onion, Jangli gobhi, wild oat, Cirsium vulgare, |
| 3.Perennial |
| Cyperus rotundus, Convonvulus, chenopodium album Ageratum conizoids, Saccharun, spontanum, Zyziphus rotundifolia, lantanta, hypomia, |
E. On the basis of Morphological Characters
| Grasses | Sedges |
| Echinochloa, Cyanodon. | Cyperaceae – C. rotundus; C. deformis. |
F. On the basis of crop weed relationship
1.Mimicry Weeds:- Such weeds are similar in external morphological with the crop.
| Weeds | Crop |
| Phalaris minor | In wheat field |
| Wild rice | In the rice field. |
2.Objectionable Weeds:- Weeds which produce seeds that are difficult to separate once mixed with crop seeds are called objectionable weeds.
| Crop | Objectionable weed |
| Paddy | Wild rice/Red rice, fatua and Cyperus distalis |
| Wheat | Bind weed |
| Okra | Abelmoschus Spp. |
| Rapeseed and mustard | Mexican poppy, Pivala dhotra |
| Lucerne | Dodder |
| Berseem | Chicory |
| onion | Wild onion |
3.Satelite Weeds:- This are come from other country and get adopted with environment.
Ex. Hypomia, lantana, Parthenium
4.Absolute weeds:- Such weeds are due to its characteristics.
Ex. Cypers rotundus (1800 weeds)
5.Rogue Weeds:- The off type crop variety in the field of certain crop variety is called rogue.
Ex. Soybean variety JS-335 seed mixture in JS -9260 variety seed.
6.Noxious Weeds:- The weeds which are undesirable, troublesome and difficult to control are called noxious weeds.
E.g Nut grass, Bermunda grass, larthenium, Striga, Orobanche, and Water hyacinth etc.
7.Volunteer Weeds:- Such weeds are grown from the fallen, seeds of previous or preceding crop in the
field. Example :- Soybean in wheat field.
8.Relative Weeds:- Some plants germinate in field without sowing (plant of same season)
Ex. Check pea in wheat field.
9.Desert weeds:- EX.- cactus.
10.Alkaline weeds:- Ex. Prickly chaff
11.Introduced or Exotic weeds/ Allien Weeds or Anthrophytes:- Many weeds move from the place of their origin by seeds or other parts to a new area and establish there and become introduces weeds such introduced weeds are called alien weeds or anthrophyes.
| Weeds | Country |
| Parthenium hysterophorus | From U.S.A |
| Lantana camera (Ghaneri) | From Shri Lanka by birds |
| Cockleber/ Gokhru (Xanthium strumarium) | Native of America |
| Orobanche spp. (Bambakhu) | Europe |
| Nut grass (Cyperus rotundus) | Eurasia |
| Water hyacinth | Tropical America (Introduced in India by Portuguese) |
| Johnson grass | Asia and southern Europe. |
12.Parasitic weeds
| Parasitic weeds | |
| Root parasites | |
| complete root parasite | Orobanche (broom rape) in tobacco |
| partial root parasite | Striga spp (witch weed) on Millets |
| Stem parasites | |
| Complete stem parasite | Cuscuta (dodder) in Lucern & barseem |
| Partial stem parasite | Loranthus in fruit crops. |
Weeds Important Study Point
| All Agriculture Important Tables | Click |
