study of the life cycle and morphology of major weeds · choto shama local name : choto shama,...

1 Life cycle and morphology of weed

© 2015 Mirza Hasanuzzaman Also available at: www.hasanuzzaman.webs.com

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STUDY OF THE LIFE CYCLE AND MORPHOLOGY OF MAJOR WEEDS

Mirza Hasanuzzaman, PhD Professor Department of Agronomy Sher-e-Bangla Agricultural University E-mail: [email protected]

Life cycle: Generally a plant starts its life from seed then it becomes a mature plant and then produces new germ cells or spores or seeds to create a new offspring. This continuous process is called the life cycle of a plant. Objectives of knowing the life cycle of weed

To determine the correct method of controlling the weeds. There are several methods to control weeds. Any one of the methods will not effective for every weed. So, the appropriate method of controlling weed can be selected due to the study of life cycle and morphology of that weed.

To determine the correct time of controlling weeds. Every weed has a critical time in its life cycle, when they can be easily controlled with the appropriate method.

Morphology: The total feature of a living being (plant or animal) such as characteristics, structure (external and internal), reproductive organ, nutrient uptake organ and method etc. is called the morphology of that living being. Objective of knowing the life cycle of weed

To determine the correct method by studying the morphology of weed for successful crop production.



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Durba

Local name : Durba, Dubla English name : Bermuda grass, Devils grass Scientific name : Cynodon dactylon Family : Poaceae Habit: Perennial grass, herb, climbing and creeping. Rhizomes and stolons grow deeply in the soil. Habitat: Dry or moist well-drained soils. Cannot persist in water logged area. Growing season: Mainly kharif but they are found all over the year. Seeds can germinate throughout the year if moisture supply is adequate. Associated crops: Aus rice, jute, sugarcane, maize etc. Propagating organ: Propagates mainly by stolons and rhizomes; produces few seeds; seeds can survive submergence up to 50 days. Leaf: Linear, grey-green, narrow. Stem: Long, smooth, and cylindrical. Inflorescence: Finger like spread. Root: Shallow, fibrous root system. Control measures: Difficult to control because detached fragments regenerate easily. Can be controlled by deep ploughing so that their rhizomes come out under the sun and destroyed.



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Boro Shama Local name : Shama English name : Burnyard grass Scientific name : Echinochloa cruss-galli Family : Poaceae Habit: It is an annual weed, resistant to climatic hazard. Similar growth habit with rice; undetectable from rice plants at early growth stages. Habitat: Found in wet and flooded soil. Seeds can also germinate under water. Growth becomes increasingly poor with continued submergence. Required similar environment as by rice. Growing season: Annual grass; seeds germinate throughout the year. Associated crops: Mainly rice, then jute, maize and sugarcane. Propagating organ: Propagated by seed, prolific seed producer. Leaf: Linear, smooth, dense green; lower side is wide and upper side is narrow, looks like rice leaf. Stem: Stem culm; hollow inter node. Inflorescence: Spikelets have long awn, panicle is long, branched. Root: Adventitious, fibrous root system. Control measures: It can be controlled by hand pulling and racking Contact poison may be used as herbicide.



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Choto Shama

Local name : Choto Shama, khude Shama English name : Jungle rice Scientific name : Echinochloa colonum Family : Poaceae Habit: It is an annual weed, resistant to climatic hazard. They are multi seasonal. Habitat: Grows in dryland soil. They cannot persist in water logging condition. Growing season: Annual grass; seeds germinate throughout the year. Short life cycle and complete several cycles in a year. Associated crops: Aus rice, jute, wheat, barley, potato etc. Propagating organ: Propagated by seed, prolific seed producer; seeds have little or no dormancy. Leaf: Linear, smooth, dense green; lower side is wide and upper side is narrow, looks like rice leaf. Has leaf blade and leaf sheath but no ligule or auricle. Stem: Stem culm; hollow inter node. Inflorescence: Spikelets have small awn, panicle is short, branched. Root: Adventitious, many tillering. Control measures: It can be controlled by racking and hand pulling. Contact poison may be used as herbicide.



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Chapra Local name : Chapra English name : Goose grass, yard grass Scientific name : Eleusine indica Family : Poaceae Habit: Annual grass, herb. Profuse tillering habit. Habitat: Dry to moist soils. Growing season: Kharif and Rabi but they are found all over the year. Short life cycle; can complete several cycles in a year. Associated crops: Aus rice, jute, sugarcane, maize and winter vegetables. Propagating organ: Propagates by seeds; prolific seed producer. Seeds can germinate throughout the year if moisture supply is adequate. Leaf: Narrow, linear and pointed tip. Stem: Erect, much dense. Inflorescence: Spike like. Root: Fibrous, extensive root system. Control measures: Can be controlled by hand pulling, ploughing and by using selective herbicide.



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Anguli Ghash Local name : Anguli ghash English name : Large crabgrass Scientific name : Digitaria sanguinalis Family : Poaceae Habit: Annual grass, herb. Habitat: Dry to moist soils. Cannot persist in water logged area. Growing season: Kharif. Associated crops: Aus rice, maize, tea and cotton etc. Propagating organ: Only by seeds; prolific seed producer. Short seed dormancy. Leaf: Lamina and leaf cover hairy, simple. Stem: Erect or creeping, dense branching. Inflorescence: Spike looks like finger. Root: Extensive root system gives it an advantage for below ground competition. Control measures: Deep ploughing, narrow leaf selective herbicide.



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Kak paya Local name : Kak paya English name : Crow foot grass Scientific name : Dactyloctenium aegyptium Family : Poaceae Habit: Annual grass. Habitat: Upland conditions; grows well in sandy soils with low moisture. Growing season: Kharif and rabi Associated crops: Serious weed of upland rice, groundnut, pulses, and sugarcane. Propagating organ: Seed, prolific seed producer. Leaf: Smooth, short hairy, wider base. Stem: Clustered in the base, erect or creeping. Inflorescence: Spike like crow foot. Root: Adventitious root system. Control measures: Hand pulling, ploughing, and narrow leaf selective herbicide.



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Mutha Local name : Mutha English name : Nut sedge Scientific name : Cyperus rotundus Family : Cyperaceae Habit: It is a perennial sedge weed. Habitat: High and medium high land and moist soil condition. Growing season: Rabi and kharif. Associated crops: Aus rice, jute and rabi crops. Propagating organ: Seed, rhizome, rootstock and tuber. Leaf: Simple, paralleled venation, upper side grooved and dense green. Stem: Its stem is called pseudostem. Stem triangular, erect, and branchless. Modified to rhizome. Inflorescence: Simple or compound and umble shape. Root: Fibrous, modified rhizome and tuber inter connected with each other. Control measures: It can be effectively controlled by puddling before transplanting of seedling. Besides, selective herbicide can be used.



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Holde Mutha

Local name : Holde Mutha English name : Yellow nut sedge Scientific name : Cyperus esculentus Family : Cyperaceae Habit: It is a perennial sedge weed. Habitat: Comparatively low land and wet soil. Growing season: Rabi and kharif. Associated crops: Aus rice, jute and rabi crops. Propagating organ: Seed, rhizome and tuber. Leaf: Erect, paralleled venation, about equal to the stem in long, sessile. Stem: Its stem is called pseudostem. Stem triangular, erect, and branchless. Modified to rhizome. Inflorescence: Yellow-brown and umbel shape. Root: Fibrous, modified rhizome and tuber inter connected with each other. Control measures: It can be controlled by racking, hand pulling and deep ploughing and puddling. Besides, selective herbicide can be used.



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Boro Dhdhia Local name : Boro karni English name : Garden spurge, milkweed Scientific name : Euphorbia hirta Family : Euphorbiaceae Habit: Annual herb, broad leaf; grows lying on soil. Habitat: Dry to moist soil. Growing season: Rabi and kharif, flowers throughout the year; can complete life cycle within a month. Associated crops: Aus rice, Jute, Rabi crops; can reduce rice yield by 30%. Propagating organ: Propagates by seed; prolific seed producer. Leaf: Dented edge, opposite. Stem: Short haired, white milky substance (latex) comes out when scraping. Inflorescence: Yellow-brown, “head” like, very small flowers bloom together in a branch. Root: Tap root system. Controlling measure: Hand, ploughing and broad leaf selective herbicide.



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Shak Notey Local name : Khuria shak, Notey shak English name : Pigweed, Green amaranth Scientific name : Amaranthus viridis Family : Amaranthaceae Habit: Annual broadleaf, herb. Used as vegetables. Habitat: Grows best in soils with no standing water. Growing season: Rabi and kharif. Germinates throughout the year if soil moisture is sufficient. Associated crops: Winter seasonal vegetables, tobacco, wheat, job, sugarcane etc. Propagating organ: Propagates by seeds; prolific seed producer. Germination occurs from a few days after harvest to about 5 months. Leaf: Lens-shaped, long petioled, pointed tip. Stem: Veined. Inflorescence: Spike, arises from the top of the stem or leaf axis, flowers are small, dense green. Root: Tap root system. Control measures: Hand pulling, ploughing, flooding and broadleaf selective herbicide.



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Kata Notey Local name : Kata notey, kata khuria shak English name : Spiny amaranth Scientific name : Amaranthus spinosus Family : Amaranthaceae Habit: Annual broadleaf, herb. Habitat: Grows best in soils with no standing water. Growing season: Rabi and kharif. Germinates throughout the year if soil moisture is sufficient. Associated crops: Aus rice, winter vegetables, pulse crops, tobacco, wheat, barley, sugarcane etc. Propagating organ: Propagates by seeds; prolific seed producer. Germination occurs from a few days after harvest to about 5 months. Leaf: Lens-shaped, long petioled with two long spines, pointed tip. Stem: Veined, spiny. Inflorescence: Spike, arises from the top of the stem or leaf axis, flowers are small, dense green. Root: Tap root system. Control measures: Hand weeding, ploughing, raking, flooding and broadleaf selective herbicide.



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Bathua

Local name : Bathua English name : Lambsquarter Scientific name : Chenopodium album Family : Chenopodiaceae Habit: Annual, erect herbaceous broad leaf weed. Habitat: It grow well in low temperature and dry land. Growing season: Rabi. Associated crops: Wheat, barley, maize, sorghum, mustard, winter vegetables, potato etc. Propagating organ: Seed. Prolific seed producer. Seeds have long viability. Leaf: Greenish or grayish green, glabrous. Simple and alternate. Stem: Smooth and branched. Inflorescence: Arises from the leaf axils and terminus of the stem and branches. Root: Tap root system. Control measures: Hand weeding, ploughing and foliage applied herbicides.



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Nunia

Local name : Nunia English name : Common Purslane Scientific name : Portulaca oleraceae Family : Portulacaceae Habit: Annual herb which grows erect and prostrate. Habitat: Moist soils and irrigated areas. Growing season: Rabi and kharif. Associated crops: Rice, wheat, barley, maize, sorghum, mustard, potato etc. Propagating organ: Seed and stem fragments. Leaf: Shiny and simple. Spirally arranged or opposite, sessile with smooth margin. Stem: Succulent, fleshy and freely branched. Inflorescence: Flowers are yellow, sessile and found solitary in the leaf axils. Root: Tap root system. Control measures: Hand weeding, ploughing and post emergence herbicides.



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Kanaibashi Local name : Kanachora, Kanaibashi English name : Tropical Spiderwort Scientific name : Commelina benghalensis Family : Commelinaceae Habit: Creeping annual/perennial broad leaf, herb. Habitat: Grows best in moist soil. Growing season: Kharif. Associated crops: Mainly T. Aman and boro rice; sugarcane, maize, jute etc. Propagating organ: Propagated by seed and stolon; vegetative growth from stem cutting is rapid. Leaf: Simple, wide lamina slightly waved; leaf sheath reddish-brown and hairy. Stem: Succulent, long, branched. Inflorescence: Flowers are blue, funnel like. Root: Fibrous and adventitious. Control measures: Difficult to control because vegetative fragments regenerate easily and are resistant to many herbicides. Hand pulling, deep ploughing, puddling and broadleaf selective herbicide.



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Kanainala Local name : Dholpata, Kanshira, Kanainala English name : Spider wort Scientific name : Cyanotis axillaris Family : Commelinaceae Habit: Annual herb, grows lying on soil. Habitat: Moist and mud as well as water logged soil. Growing season: Rabi and kharif. Associated crops: Transplanted aman rice, aus rice and jute. Propagating organ: Seed and stolon. Leaf: Linear, simple, sword like elongated pointed tip; fleshy leaf sheath encircled the stem. Stem: Creeping, branched, fleshy and slight violet. Inflorescence: Light violet flower arises from leaf axis. Root: Fibrous and adventitious root system Control measures: Hand weeding, ploughing and selective herbicides.



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Pani kochu Local name : Pani kochu English name : Monochoria Scientific name : Monochoria vaginalis Family : Pontederiaceae Habit: Annual or perennial broadleaf, herb. Habitat: Sub aquatic to aquatic conditions. Growing season: Kharif and rabi. Associated crops: Deep water rice, jute, taro etc. Propagating organ: Seed, stolon and sucker; seeds can germinate throughout the year. Leaf: Arises from the stem as cluster and long petiole. Stem: Smooth, rounded and covered by leaf petioles. Inflorescence: Spike. Flowers are white or bluish violet. Root: Tap root system. Controlling measure: Hand pulling, ploughing, and broadleaf selective herbicide.

study of the life cycle and morphology of major weeds · choto shama local name : choto shama,...

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