This document summarizes important weed flora found in transplanted and direct seeded rice in Nepal. It describes several grass and sedge species that are dominant weeds, such as Cyperus difformis, Leptochloa chinensis, and Echinochloa crusgalli. It also outlines several broadleaf weeds that commonly impact rice crops, including Lindernia spp., Ammania baccifera, and Alternanthera sessilis. The ecology of each weed is discussed, such as their growth habit, reproduction method, and environmental preferences. In total, over 30 different weed species that affect rice production in Nepal are identified and characterized.

1. Important Weed Flora of Transplanted and
Direct Seeded Rice
Presented by
Pratima Pokhrel
WS-01M-2023

2. Rice
 Rice (Oryza sativa) is the major cereal crop and is staple food to about 3 billion
population of the world.
 Rice is the major cereal crop in Nepalese agriculture both in the area of 1.47 million
ha as well as production of 5.15 million tons.
 In Nepal, rice is planted mainly by two principal methods i.e. transplanting and
direct seeding method.
 The problem of weed competition with rice is of great economic importance in the
country because it causes a 10–35% reduction in grain yield.

3. Direct seeded rice:
 Direct seeding is a crop establishment system wherein rice seeds are
sown directly into the field.
Transplanted rice :
 Transplanting consists of preparing seedlings in nursery and then
planting these seedlings in the prepared main field.

4. Weed is an unwanted plant.
Generally, plant in wrong place called as weed.
Grasses are dominant in irrigated/ transplanted systems.
Sedges are dominant in rainfed systems.
Weed problems are more severe in aerobic and direct-seeded rice when
compared with irrigated rice.
Nearly 134 weed species identified from rice field belongs to 32
taxonomic families.
The study of how a weed interacts with other plants, its habitat, and other
weeds is known as “weed ecology”.
Weeds of rice and their ecology

5. Weeds of Direct-Seeded Rice

6. Grasses
Scientific name: Cyperus difformis
Common name: Common sedge(motha)
• Family: Cyperaceae
• Ecology: This is an annual herb with one to many
thin, soft erect stems reaching over 30 centimeters
in maximum height.
• The small flower umbrella plant grows well in
flooded or moist fertile soils and common in
lowland rice.
• found on poorer sandy or clay soils in fallow lands.
• propagates by seeds and produces seeds throughout
the year.
Scientific name: Leptochloa chinensis
Common name: Red sprangletop
Family: Poaceae
Ecology: Red sprangletop propagates by seeds or
vegetatively by rootstocks.
Germination does not occur when seeds are submerged in
water.
L. chinensis grows from near sea-level up to 1400 m
altitude.
Germination was strongly stimulated by light and warm
fluctuating temperatures

7. Scientific name: Ludwigia perennis
Common name: False primerose (ल्वा झार)
Family:Onagraceae
Ecology:Upland.It is highly tolerant of
fluctuating water levels.
• The periderm of the plant tissues swells
rapidly when immersed in water: this is
probably a defence against waterlogging .
• Responds strongly to application of
nitrogenous fertilizer (up to 100 kg/ha) by
increased dry matter accumulation, which
may increase problems of weed control in
heavily fertilized ricefields.
Common name: Scirpus spp. (Bulrush)
Scientific name: Scirpus
Family: Cyperaceae
Order: Poales
• Ecology: Perennial weed of low land paddy
• Erect and strongly tillering upto 0.75m
• Dormancy:2-3 months
• Elevation: upto 2000

8. Broad leaf weeds
Scientific name: Monochoria vaginalis
Common name: Pickerel weed
Family: Pontederiaceae
• Ecology: M. vaginalis is a fleshy, tufted, annual or
perennial herb with a glabrous, shiny appearance and
a short rhizome.
• Reproduction is mainly from seed, with occasional
new growth from tubers.
• Its property of discontinuous germination allows it
to evade control.
Scientific name: Sagittaria sagittifolia
Common name: Arrowhead
Family: Alismataceae
Ecology: Sagittaria sagittifolia is a stoloniferous aquatic
perennial herb that reproduces by seed, plant division, and
tubers
• The plant spreads, forming large stands in areas of slow
moving or stagnant water.
• Very difficult to fully control due to the ability of the plant
to regenerate from fragments and the extensive rhizome
system.

9. Scientific name: Commelina benghalensis
Common name: Benghal dayflower, tropical spiderwort,
Family: Commelinaceae
Ecology: Found on upland, lowland, disturbed sites,
forest edges, road sides, agricultural sites, and home
gardens. Moist to dry places
• Germinates best in full light; somewhat tolerant
of herbicides; annual in temperate zones; prefers high
• fertility; single plant can cover a large area; useful
forage and human food.
Scientific name.: Ammania baccifera
Common Name: Agni buti
Family: Lythraceae
Ecology: It is annual, dicot and herbaceous plant and can
be found in marshes, swamps, rice fields and water
courses at low elevations during rainy season.
A. baccifera occurs in wet locations, very often as a
weed in rice fields in the lowland, up to 1200 m altitude.
Maximum alkaloid synthesis was found in plants at the
fruiting stage, under moderate light intensity and with a
photoperiod of 16 hours.
The application of NPK-fertilizer enhanced the alkaloid

10. Scientific name: Lindernia spp. (Lindernia)
Common name: Oonmudia
Family: Scrophulariaceae
Ecology: Small annual or perennial weed, reproducing by
seed,; particularly rice fields, grassland, irrigated crops.
Scientific name: Eclipta alba
Common name: False daisy(jal bhangra)
Family: Asteraceae
Ecology: Found in: lowland, upland; Growth habit: herb;
prostrate to erect, much-branched; up to 1.0 m; Life
cycle: annual; reproduction: via seeds; no emergence
from depth; C3 plant; saline-tolerant; often in fi eld
margins; somewhat
tolerant of butachlor

11. Scientific name: Hedyotis spp. (Hedyotis)
Common name:Hedyotis
Family: Rubiaceae
Ecology: Herbs or subshrubs, apparently biennial
or perennial, found in tropical and subtropical
wastelands
Scientific name: Aeschynomene spp
Common name: Aeschynomene
Family: Leguminosae
Ecology: It is an annual or perennial herb, that often
grows in wet, muddy habitat, such as floodplains,
swamps, and paddy fields, found in tropical and
subtropical regions and elevation: up to 1,500 m,
reproduce via seeds, C3 plant

12. Scientific name: Rotala spp.
Common name: Rotala
Family: Lythraceae
Ecology: Aquatic perennial plant, found in a semi-emersed
state at the edges of paddies and in moist areas, fast growth
rate, Temperature: 22-28°C.

13. Scientific name: Panicum spp.
Common name: Panicgrass
Family: Poaceae
Ecology: Native throughout the tropical regions of
the world, They are often large, annual or perennial
grasses, growing to 1–3 m tall, ; drought-tolerant;
reproduction: rhizomes, seeds; prefers sandy soils;
acid- and salt-tolerant; deep plowing increases rate
of spread; after establishment can survive moderate
drought; fodder
Scientific name: Fimbristylis spp. (Fimbristylis)
Common name: Jwane jhar
Family: Cyperaceae
Ecology: may emerge throughout season; may produce
multiple generations in one season; Found in upland and
low land; very heterogeneous species; saline-tolerant; C4
plant; better adapted to drier soils; useful for mat-making
Sedges

14. Scientific name:Echinocloa glabrescens
Common name: Samo ghans
Family: Poaceae
Ecology: Adapted to wet places, It grows on
ditches, low areas in fertile croplands and wet
wastes, often growing in water, one of the world’s
worst weeds; soil saturation
strongly reduces emergence of buried seeds;
responsive to nutrients; profuse root production;
good forage; C4 plant; encouraged by zero tillage
Scientific name: Echinochloa crusgalli
Common name: Banyard grass (sawank)
Family: Poaceae
Ecology: Adapted to wet places, grows on ditches,
low areas in fertile croplands and wet wastes, often
growing in water, one of the world’s worst weeds; soil
Saturation strongly reduces emergence of buried seeds;
responsive to nutrients; profuse root production; good forage;
C4 plant; encouraged by zero tillage

15. Scientific name: Cyperus rotundus
Common name: Purple nut sedge(motha)
Family: Cyperaceae
Ecology: Found in cultivated fields, farmlands,
neglected areas, wastelands, grasslands, at the edges
of forests, and on roadsides, sandy or gravelly
shores, riverbanks and irrigation canal banks; elevation:
upto 1800 m; C4 plant; saline-sensitive; tubers may be
viable for several years; tubers consumed by humans;
forage
Scientific name: Digitaria ciliaris
Common name: southern crabgrass (chitrey banso)
Family: Poaceae
Ecology: Found in tropical and temperate regions; tolerates
defoliation; Growth habit: creeping, tufted with prostrate to
erect culms; up to 0.6 m very responsive to nutrients; C4
plant; shade-sensitive, reproduce via seeds, Elevation: up to
2,000 m

16. Scientific name: Cyperus iria
Common name: Yellow sedge
Family: Cyperaceae
Ecology: Found in: lowland, upland; Growth habit: erect;
tufted up to 0.8 m; Elevation: up to 1,200 m; germinates
best in full light; C4
plant; may have multiple generations in one season;
prefers lower elevations
Scientific name: Eleusine indica
Common name: Goose grass (Kode jhar)
Family: Poaceae
Ecology: Found in: upland; Growth habit: stems erect or
ascending, branched; upto 0.6 m; one of the world’s
worst weeds; C4 plant; multiple generations in one
season; can emerge from soil depths of up to 0.08 m;
Elevation: up to 2,000 m; reproduce via seeds

17. Scientific Name: Leptochloa mucronate
Common Name: Red Sprangletop, Sprangletop
Family: Poaceae
Ecology: Suited to tropical, subtropical or warm
temperate climates; Growth habit: tufted, erect,
and slender; sometimes with
reclining stems; up to 1.2 m
Scientific name: Ischaemum rugosum
Common Name: Wrinkle grass
Family: Poaceae
Ecology: Growth habit: tufted, ascending to erect, and much
branched; up to 1.0 m; Life cycle: perennial; Elevation: up to
2,400 m Light: sunny; shade-tolerant; red leaf sheaths at the
base; new seedling cohorts emerge after drainage from up to
0.05 m soil depth; responsive to fertilizer; acid-tolerant; good
forage if young; germinates on surface of saturated soil; C4
plant

18. Weeds of
Transplanted rice

19. Broadleaf weeds
• Scientific name: Eclipta alba
• Common name: False daisy(jal bhangra)
• Family: Asteraceae
• Ecology: This species grows commonly in moist
• places as a weed in warm temperate to tropical
• areas worldwide.
Scientific name: Commelina benghalensis
Common name: Benghal dayflower, tropical
spiderwort,
Family: Commelinaceae
Ecology: Found on upland, lowland, disturbed sites,
forest edges, road sides, agricultural sites, and home
gardens. Moist to dry places

20. Scientific name: Alternanthera sessilis
Common name: sessile joyweed(Bhirung)
Family: Amaranthaceae
Ecology: found in lowland and upland, Moisture: wet
to moist; more terrestrial than aquatic
lowland, upland
Growth habit: prostrate, creeping or ascending; many
suberect branches, up to 1 m
Moisture: wet to moist; more terrestrial than aquatic
Competitivfloodingeness: moderate
Seed contaminant: unknown
Cultural control: flooding, hand weeding or tillage
Scientific name: Ageratum conyzoides
Common name: Tropic weed, goat weed
Family: Asteraceae
Ecology: Found in moist to dry place of land
annual Seed wt: 0.1
Method(s) of reproduction: seeds
Maturity time: quick fl owering and short-lived, as little
as 2 months
Dormancy: 50% of seeds can germinate immediately; light
required for germination
Flower: white to pale purple/blue
Elevation: up to 3,000 m
Light: shade-tolerant

21. Scientific name: Amaranthus spinosus
Common name: Spiny amaranth, Spiny pigweed
Family: Amaranthaceae
Ecology: Life cycle: annual Seed wt: 0.2 Method of
reproduction: seeds; no light requirement for germination;
Flower: pale green-purple tinge; Elevation: up to 1,800 m
Light: sunny; shade-sensitive; ; C4 plant; prefers fertile soils
and higher temperature

22. Scientific name: Cynodon dactylon
Common name: Bermuda grass, dubo
Family: Poaceae
Ecology: Growth habit: prostrate to ascending;
up to 0.4 m; Life cycle: perennial Seed wt: 0.3
reproduction: rhizomes and stolons, seeds;
Elevation: up to 2,300 m; C4 plant; alkaline and
acid-tolerant; flood- and drought-tolerant;
numerous
biotypes
Sedges
Scientific Name: Echinochloa colona
Common name: Shama millet (सामा घााँस)
Family: Poaceae
Ecology: Growth habit: tufted and erect; up to
0.6 m; Life cycle: perennial; reproduction:
seeds, stolons; Elevation: up to 2,000 m; soil
saturation strongly reduces emergence of buried
seeds; responsive to nutrients; profuse root
production; good forage; C4 plant; encouraged
by zero tillage

23. Scientific name: Digitaria ciliaris
Common name: southern crabgrass (chitrey banso)
Family: Poaceae
Ecology: Found in tropical and temperate regions;
tolerates defoliation; Growth habit: creeping, tufted
with prostrate to erect culms; up to 0.6 m very
responsive to nutrients; C4 plant; shade-sensitive,
reproduce via seeds, Elevation: up to 2,000 m
Scientific name: Panicum spp.
Common name: panicgrass
Family: Poaceae
Ecology: Native throughout the tropical regions of the
world, They are often large, annual or perennial grasses,
growing to 1–3 m tall, ; drought-tolerant; reproduction:
rhizomes, seeds; prefers sandy soils; acid- and salt-
tolerant; deep plowing increases rate of spread; after
establishment can survive moderate drought

24. Scientific name: Imperata cylindrica
Common name: blady grass, cogon grass(sirru)
Family: Poaceae
Ecology: Found in: upland; Growth habit: erect, tufted,
and unbranched; scaly rhizomes; up to 2 m; perennial
reproduce via seeds and rhizome; C4 plant; acidand
alkaline-tolerant; prefers light-textured soils; many
infested fields are abandoned; burning does not injure
rhizomes
Scientific name: Panicum spp.
Common name: panicgrass
Family: Poaceae
Ecology: Growth habit: creeping; erect and
branching stems; up to 1.0 m; Growth habit:
creeping; erect and branching stems; up
to 1.0 m; Life cycle: perennial; reproduction:
rhizomes, seeds; prefers sandy soils; acid- and
salt-tolerant; deep plowing increases rate of
spread; after establishment can survive moderate
drought

25. Scientific name: Scripus junicoides
Common name: Club rushes
Family: Cyperaceae
Ecology: Found in lowland rice, shallow ponds,
streams, and drains. Emerges directly from seeds;
Scientific name: Eleusine coracana
Common name: crowfootgras (kode banso)
Family: Poaceae
Ecology: Both upland and lowland

26. Thank you!!!