Transcript 4.weed flora and weed distribution in mango added

WEED FLORA AND
WEED DISTRIBUTION
IN MANGO
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 Mango (Magifera indica L.) occupies major area
under fruits in the country. It is adaptable to a wide
range of soil and climatic conditions provided severe
and recurring frosts in winter do not endanger the
young trees.
 There are numbers of varieties grown in India and
some are of export quality. Veneer grafting and stone
grafting are found to be the best method for mango
propagation.
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The major monocot weeds that occur in mango orchards are Cynodon
dactylon and Cyperus rotundus and dicot weeds are Bidens pilosa,
Tridax procumbens and Phyllanthus maderaspatensis.
Grassy weeds are distributed about 60-70
per cent in mango cultivation followed by
sedges and broad leaved weeds.
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Cynodon dactylon Pers
In black soils and in dryland is a
noxious weed and once a field is infested
with it, cultivation becomes impossible.
It belongs to the family
Graminae
(Poaceae)
and
common name is Bahama
It is considered as one of the ten Grass, Hariyali. In tamil it
worst weeds in the world and
is called as Arugampullu
problematic in all tropical and
subtropical areas in dry land and
garden lands.
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Cynodon dactylon Pers.
A perennial grass extensively creeping by means of scaly
rhizomes or by strong flat stolons, very common in plains and
hills slender and grows upto 7.5 to 30 cm height.
The underground stems are hard, brittle, thick, pale white in
colour and covered with short scale-leaves and occur at varying
depth in soil. Leaves are linear, finely acute, 7.5 to 12.5 cm
long, spikes 3 to 6. Propagated by through seeds and
underground stolons.
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Cyperus rotundus L
Family is Cyperaceae and common name is Nut
Grass, Nutsedge. In tamil it is called as Korai
kizhangu. Stoloniferous, stolons not bulbiferous,
stems trigonous, up to 1 m high, and tubers not
zoned. Stem sparsely tufted. Leaves shorter or
longer than stem, narrow, numerous, bracts
usually 3 and up to 60 cm long.
Cont…
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Cyperus rotundus L
Floral biology:
spikelets spreading, linear to lanceolate, up to 2.5 cm long;
glumes imbricate, plicate, pale-brown or chestnut-brown,
sometimes with a reddish tinge; nut trigonous, broadly
obovoid, grayish-black.
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Bidens pilosa L.
It is a broad leaved weed coming under
Compositae (Asteraceae) family. It grows erect
and looks like glabrous or pilose or pubescent,
annual herb.
Leaf arranged in opposite side, variable.
Heads is long stout peduncles, variable in
length, with or without rays, in corymbose
panicles, ray flowers 1-seriate.
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Bidens pilosa L.
Subtending the bisexual flowers
corolla of ray flowers ligulate, of
disk flowers tubular, limb 5-lobed.
Fruit is achenes black, slender,
exceeding the involucre pappus
with 2-4 short, stout, spinescent
awns
covered
with
recurved
hooks. Propagation is mainly by
achenes.
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Tridax procumbens L.
It is a broad leaved weed coming
under Compositae (Asteraceae)
family. The plant has procumbent,
hispid, weak, straggling perennial
herb. Stem is round and covered
with sparsely distributed hispid Leaves
opposite,
ovate
or
hairs.
lanceolate, deeply serrate. Flower
heads solitary, long peduncled, 2-3
times as long as the stem,
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WEED FLORA AND WEED DISTRIBUTION IN MANGO
Tridax procumbens L.
Heterogamous, rayed; ray flowers female, fertile, two
lipped, outer lip large, 3 –fid, inner small, 2 lobed disc
flowers bisexual, fertile, tubular, limb elongate.
Involucre of bracts campanulate, few seriate,
outer broad, herbaceous, inner scarious;
receptacle flat or convex; palaea membranous;
corolla of female flowers ligulate, of bisexual
flowers tubular. Fruit is achens brown, oblong,
silky; pappus of short feathery bristles, shining.
Propagation is through achenes.
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Phyllanthus maderaspatensis L.
It belongs to the family Euphorbiaceae
and common name is Bahama Grass,
Hariyali. In tamil it is called as
Melaanelli.
It is grows erect or decumbent
herb with spreading branches.
Leaves glabrous, subcoriaceous,
scattered, subsessile, cuneatly
obovate,
glaucous
beneath,
stipulate
stipules
peltate,
lanceolate, membranous.
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WEED FLORA AND WEED DISTRIBUTION IN MANGO
Phyllanthus maderaspatensis L.
Flowers very small, monoecious, male facicled,
female shortly pedicelled, solitary; sepals broad,
green with white margins rounded or obcuneate; disk
glandular in both; stamens 3, almost sessile on the
column, erect, apiculate.
ovary superior, tricarpellary, syncarpous,
styles free, minute, 2 –lobed.
Fruit looks like Globose, schizocarpic; seeds
striated, trigonous. Propagation is mainly
through seeds.
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