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| AGRICULTURE TRIBUNE | Monday, February 10, 2003, Chandigarh, India |
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TREE TALK
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TREE TALK Willow and "bains," respectively, are common English and vernacular names for a number of sister trees of the genera Salix. These are fast growing and yet medium-sized deciduous trees belonging to the plant family Salicaceae. They are of enormous ecological and economic importance. Distribution
The Salixes and
poplars, two sister genera of the salicaceae group of trees are found
growing naturally in cold areas, especially mountains like the
Himalayas, Nilgris or the Hindukush in the northern hemisphere. These
are usually cultivated in the Himalayas from nearly 1000 to 3000 m
above the mean sea level. Important native Indian Salix species are
Salix tetrasperma, S. acmophylla, S. oxycarpa, S. wallichiana, S.
elegans, etc. The Salixes are cultivated in India for their valuable
soft and elastic wood, foliage for fodder and ornamentation of
landscape. Of the members of this family introduced from Europe, the
most important and useful one is Salix alba. It is popularly called
white willow and was introduced in the Kashmir valley in1916-17 for
production of wood for cricket bats.
Phenology
The leaves of Salix are
alternate, simple and stipulate. Buds being enclosed in scales, shape
lanceolate, they measure about 8-15 cm in length, 3-4 cm in width and
are glabrescent above and glaucus beneath. Old leaves are shed during
autumn. New leaves appear during February-March. Flowering also occurs
nearly simultaneously during March-April. The flowers are dioecious.
Both male and female flowers are borne on terminal catkins. The fruit
appears during May-June. These are 2" to 4" long. The bark,
nearly 1 cm thick, is grayish (dark) with criss-cross fissures. Soil
requirement The natural habitat of Salix is sandy alluvial and/or
sandy loam soil with a lot of moisture. Some of its species also grow
happily in swampy locations having clayee soil. The stands growing in
dry pockets, however, put on slow growth and also tend to become
stunted. The Salixes are generally light-demanding species. These are
frost hardy and sensitive to drought. The species coppice and pollard
very well.
Regeneration Willows come up naturally from seed
drifting/ floating along river banks, stream beds, depressions and
bunds of agricultural paddy fields having lot of water/ moisture
content. The species can be easily raised artificially from cuttings
and sets. These are commonly raised as ornamental trees along canals,
small water channels, roadside avenues, etc.
Utilities The
foliage of Salix serves as green fodder for cattle. Sheep and goats
even gnaw the bark on tender shoots, including stem of young plants.
The new twigs being elastic, are used for making baskets. The species,
being fast-growing trees, attain exploitable diameter of 30 cm in
about 20-30 years. The sapwood is greyish white, and heartwood greyish
brown with indistinct annual growth rings. The texture being soft,
willow wood is easy to saw and plane. It weighs nearly 14 to 16 kg per
cubic foot and considered excellent for making gunpowder charcoal. The
wood, fetching about Rs 1000 per cft, is used for manufacture of
sports gear like cricket bats, the handle part of hockey sticks and
badminton racquets. It is also used for manufacture of matchsticks,
plywood, planking, panelling and cheap furniture. Willows planted
along canal banks and raised road/ rail embankments act as a
soil-binding agent against erosion. The best part is that Salixes do
not hamper the growth of agricultural crop(s) growing side by side.
These trees serve as a good refuge for birds, which save crops from
insects and rodents.
Medicinal value As per the Unani
system of medicine the leaves of willows give "cold dry"
effect while the flowers display "cold wet" effect. Sleeping
on a bed of willow leaves is beneficial in treating heart problems and
body pain. A squash of fresh leaves is believed to control dysentery,
earache, worms, etc. Inhaling the aroma of fresh flowers of willow
relieves headache and mental tension. A distillate extract of willow
flowers is much more effective in relieving the above
ailments. Willows can be profitably planted and propagated on bunds
and also by engineers and architects along roads, railway tracks,
canals and or in housing colonies along avenues, etc. |
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Orchardists, be alert in spring Spring brings prolific blooms and relief from the intense winter. Most of the fruit trees, shrubs and other seasonal plants being grown in Punjab sprout during this period and induce hope of good crop. This warm climate activates all creatures. February-March, a period of siblings, is very critical for fruit set and its further development. Any setback at this stage reduces the yield drastically and farmers should be alert. There are a number of insect pests that become active during this period on fruit crops like citrus, guava, pear, peach, mango, and grapes. It is very important to control the various insect pests at this stage to reduce the damage to flower buds, blooming flowers and young foliage. Some of the major insect pests that appear during spring are discussed here. Mango Mealy
bug: The pest does a lot of damage during the flowering and
fruiting stages from January to April when young nymphs crawl up the
trees and congregate on growing shoots and panicles. The pest can be
managed by digging or ploughing the soil around the trees during
summer to kill the eggs. The nymphs should be prevented from crawling
up the trunk by applying a slippery band at the base. The slippery
band can be prepared by applying a 15-20 cm wide sheet of alkathene to
the basal end of the stem and secure both its upper and lower edge
with 2-3 nails (2 cm). Cover the lower end with compacted soil around
the lower edges of the alkathene sheet so that nymphs are prevented
from climbing up. Wipe the band occasionally during rains. In case of
severe emergence apply methyl parathion 50 gm dust (Follidol 2%) on
the compacted soil to kill the nymphs. Mango hoppers: Hoppers
are the most serious pests of mango. Two species are prevalent in
Punjab and are active during February-March at the time of flowering.
The nymphs and adults suck the sap from the tender leaves and
panicles, which become sticky and sooty. Young fruits and dried up
inflorescence fall off as summer winds blow. Two sprays of
insecticides are essential to reduce the menace: first at February-
end and the second at March- end with 500 gm Hexavin 50WP (Carbaryl)
or 400 ml Malathion 50 EC or 350ml Thiodan 35EC (Endosulfan) in 250
litres of water. Mango scale: Scale sometimes appears as a
pest in certain localities. It inflicts damage by sucking the sap from
leaves. The infestation can be reduced by spraying 300ml Methyl
parathion 50EC in 500 litres of water in March.
Grape Grapevine
thrip: The nymphs and adults rasp on the ventral surface of tender
leaves and flower stalks, and suck the oozing sap. This leads to
leaves developing silvery white patches and generally curling and
drying, while attack on flowers induces shedding. The infestation of
flowers and young berries causes heavy damage to fruit setting and
scab formation on berries. Hot weather is favourable for pest
incidence. The attack occurs during February-March. The control
measures targeted at early stage (February-March) are more effective
compared to the late stage because at this time shedding of leaves
occurs. To control the pest, spray 500 ml Malathion 50 EC in 500
litres of water per 100 vines once before flowering and again after
fruit set. In Perlette cultivars, 500gm Hexavin 50 WP (Carbaryl) in
500 litres of water should be preferred as it also looks after
thinning of berries apart from thrip control.
Pear Leaf
hopper and aphid: At times these pests cause serious damage to the
plants by sucking the cell sap from leaves, tender shoots and fruits.
Spray 500gm Hexavin 50 WP (Carbaryl) or 250ml Rogor 30EC (Dimethoate)
in 500 litres of water. Mite: Mite attack is generally seen
in April-May. Its feeding results in brownish spots and if the
incidence is high, the whole leaf becomes pale and later on dries and
falls down. Spray of 500 ml Rogor 30EC (Dimethoate) or 1000ml Kelthane
18.5EC (Dicofol) or 500ml Fosmite 50EC (Ethion) in 500 litres of water
to control the pest.
Citrus fruit Leaf miner: Citrus
leaf miner is one of the most serious pests in nurseries and young
plantations during flushing season. The pest is active from March to
November, with its peak infestation period from mid-April to mid-June
and again during September-October. The larvae attack tender leaves by
making shiny and silvery serpentine mines. They also mine young tender
shoots. The leaves become distorted and crumpled. Severe infestation
may cause defoliation of the plantations. Attack of leaf miner also
encourages the development of citrus canker. The infestation can be
reduced by spraying 250 ml Sumicidin 20EC (Fenvalerate) or 500 ml
Ripcord 10EC (Cypermethrin) or 1750 ml Decis 2.8EC (Deltamethrin) or
625ml Nuvacron 36SL (Monocrotophos) at fortnightly intervals during
flushing period in 500 litres of water. Citrus psylla: The
damage is caused by both nymphs and adults. The pest is active from
March to November, but its population density is more from April to
September. It also acts as a vector of greening disease. Almond-shaped
eggs are laid in the fold of half-opened leaves, on petioles or
between flower buds. Orange yellow nymphs and grey adults suck the
cell sap from the growing shoots, which ultimately dry up. To control
the pest, spray 625 ml Nuvacron 36SL (Monocrotophos) or 670ml Rogor
30EC (Dimethoate) in 500 litres of water. For the effective control of
the pest, spraying must be done at first or second instar larval
stage. White and black fly: Both nymphs and adults suck the
cell sap from the tender leaves and reduce plant vigour. White-fly is
active from March to November with its two peak periods of
infestation, i.e., during spring (April-May) and autumn
(September-October), and maximum emergence coincides with the
initiation of new flush. Hot and dry conditions and dense plantation
induce more pest population. Under heavy white fly infestations sooty
mould develops that affects the photosynthetic activity of plants.
Spray 1000ml Fosmite 50 EC (Ethion) or 1250ml Hostathion 40EC (Triazophos)
or 1140 ml Thiodan 35EC (Endosulfan) in 500 litres of water during
April-May and again during September-October. Bark-eating
caterpillar: Bark-eating caterpillar is found to infest neglected
and old orchards. The pest causes damage by boring holes into the stem
and branches. It feeds on the bark under the cover of its excreta.
Besides citrus, it also attacks peach, pear, plum and guava plants.
For control remove the webbing and inject kerosene oil into the holes
in January-February. Treat all alternate host plants in the
vicinity.
Peach Peach black aphid and mite: These
pests cause damage by sucking cell sap from the bark of the stem,
limbs and branches from mid-March to June. These pests can be managed
effectively by spraying 500ml Malathion 50Ec in 500 litres of water on
colonies on the stem and limbs as soon as the pest congregates on
these parts. Spray the tree when the sun is high.
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