Insect Pest Management Tmnehs Gov In-Free PDF

  • Date:21 Mar 2020
  • Views:41
  • Downloads:0
  • Pages:11
  • Size:6.86 MB

Share Pdf : Insect Pest Management Tmnehs Gov In

Download and Preview : Insect Pest Management Tmnehs Gov In

Report CopyRight/DMCA Form For : Insect Pest Management Tmnehs Gov In


Insect Pest Management 161, l Pests vary with age and stage of the tree Therefore collect information on pest damage. in relation to the phenology growth patterns of the trees Read books take help of. experts or decide yourself for the optimum time to apply control methods. There is a list of pest control options Consider the control options available and select. from the list which is the best suited to your current circumstances to minimize the use. of chemicals, There are chemicals which have less effect on natural enemies Therefore select chemicals. which minimize adverse effects on beneficial insects. l Keep your orchard vigorous Make attempts to optimise the nutrition of orchard because. pest attacks are usually reduced in vigorously growing healthy trees. l Realise that centre opening skirting and hygiene like pruning operations can reduce. some pest problems e g scale mite by altering the density of the tree but may increase. others e g shoot borer by encouraging flush growth. Important Insect Pests, Nearly 42 insect species and mite pests have been reported to attack litchi trees and fruits in. different stages of growth nevertheless litchi is relatively free of any serious pests Fruit borers. bugs nut borer leaf rollers and mites are the important pests affecting litchi production. 1 Erinose Mite,Erinose mite is a major litchi pest The. incidence of litchi mite is seen during March,which remains active up to June July Severe.
infestation has been observed in Bihar during,March September and its population decline. from November February However mites,remain active throughout the year in one. stage or the other It is found active on litchi,trees from January to October and under. hibernation in adult stage under the hairy and,velvety growth erineum from November to. December on the under surface of the leaf,The adults start multiplying from the.
end of March and the peak activity is noticed,around July The female adults lay eggs. singly at the base of the hair on the lower,surface of the leaves The eggs hatch within. 2 3 days and newly emerged nymphs feed,on soft leaves Fig 14 1 Fig 14 1 Mite infestation. 162 A Manual for Litchi Production,PRODUCTION,Both nymphs and adults damage the leaves. inflorescence and young developing fruits They, puncture and lacerate the tissues of the leaves with.
their stout rostrum and suck the cell sap As a result. of its infestation undersurfaces of the infested,leaves show abnormal growth of epidermal cells. in the form of hair like velvety growth of chocolate. brown colour In some cases the mites cause galls, or wart like swellings or depressions on the upper. surface of the infested leaves Chocolate brown,velvety growth on the ventral surface of leaves. indicates the presence of this pest The attacked,leaves become thick curl wither and ultimately. fall off Fig 14 2 The infestation generally begins. from the lower portion of the trees and gradually,extends upwards In addition to leaves the mite.
also infests the newly formed leaf bud inflorescence. Fig 14 2 Velvety growth on mite affected leaves and epicarp of the newly formed fruit The attacked. leaf buds fail to bear flower or fruit The growth of. green patch on the epicarp indicates the mite infestation on fruits Young plants and plantlets. in nurseries are very susceptible and could even be killed if leaf drop is excessive Dispersal. of the erineum mite from one orchard to the other usually takes place through old infested. litchi leaves or by winds The current of the wind carries the erineum along with the mite from. one orchard to the other and initiates infestation in uninfested orchards Planting material. obtained as layers may also be source of infestation if they have been taken from trees with. the mites Later infestations occur when the mites are moved around the orchard by direct. contact between trees or carried around by orchard workers wind and bees. Management, Litchi mite control measures must be preventive Once the mite is established it is almost. impossible to eradicate hence depending upon infestation it is recommended that. l Layers should be prepared only from non infested plants. l Layer saplings may be sprayed with 0 05 per cent dimethoate when they leave the. nursery Prior to planting out the operation should be repeated twice at 10 14 day. l The leaves should be checked regularly for symptoms over summer and autumn All trees. in an orchard are not to be flushed or infested at the same time Therefore branches. infested with the mite should be cut off and burnt. Insect Pest Management 163, l After harvesting in June infested branches must be removed. l In September October trees must be treated just prior to vegetative flushing with 0 05. per cent dimethoate either alone or in combination with 0 12 per cent dicofol Spraying. should be repeated two weeks later and monthly thereafter until new growth is free of all. symptoms of infestation Infested leaves should be gathered and burnt or buried deeply. into the ground, l In December January just before flush flower buds the affected shoots must be removed. and spraying of 0 15 kelethane may be done In the month of Feb two sprays one. each before and after flowering have been found useful. 2 Bark Eating Caterpillar,Litchi is damaged to a considerable extent. by the bark eating caterpillars which attack,trees of all ages particularly the older ones.
lowering their vitality They bore into trunk,main stems and thick branches of litchi trees. Fig 14 3 They have a wide range of host,plants including litchi The old shady and. neglected orchards are more prone to attack,by this pest When severely infested the. entire branch or tree may die,The female moth lays eggs in cuts and. crevices in the bark in cluster in early June,Egg hatches in 8 to 10 days and newly.
emerged caterpillars come out The newly Fig 14 3 Bark eating caterpillar damage. emerged caterpillars start nibbling at the,bark The attack by this pest is characterized. by the presence of long winding thick blackish or brownish ribbon like masses composed of. small chips of wood and excreta both of which intermix with the help of adhesive material. secreted by the caterpillar After 2 3 days larvae bore into the trunk or main branches usually. at the forking place and make tunnel downwards There is only one larva in each hole and. there may be 2 16 holes in each tree depending upon the intensity of infestation and age of. the tree By continuously devouring the tissues it tunnels through the stem and branches The. caterpillars remain within the bored holes during day and come out at night to feed upon the. bark The attacked trees show the presence of windings and silken galleries full of frass and. faecal matter As a result of feeding in the trunk or main branches the translocation of sap is. disrupted and in case of severe infestation the growth of tree is arrested Fruiting capacity of. tree is adversely affected Severe injury weakens the stem resulting in drying of the branches. and finally of the tree itself,164 A Manual for Litchi Production. PRODUCTION,Management, l The caterpillars can be killed by inserting an iron spoke into the tunnels. l This insect has also been successfully controlled by injecting kerosene oil into the tunnel. by means of a syringe and then sealing the opening of the tunnel with mud. l Another method of control is dipping a small piece of cotton in any of the fumigants like. carbon bisulphide chlorosal or even petrol and introducing it into the tunnel and sealing. the opening with clay or mud, l Remove the webs from tree trunks and put emulsion of DDVP 0 05 in each hole and. plug them with mud Mix chlorpyrphos 2 ml per litre of water and apply the bark eating. caterpillar infested area with a brush at 15 days interval. l As a preventive measure spraying of the attacked trunk and branches with 0 05 DDVP. may be done,3 Litchi Leaf Roller,The incidence of leaf roller is reported during.
July to February The number of larvae is,the highest during December to February. preceding flowering season of litchi The,breeding season of the leaf roller on litchi. leaves is from August to February when new,leaf flush is available and restricted breeding. takes place during off season March to July,on alternate hosts such as kath jamun Eugenia. jambolana and chhota amaltas Cassia tora,growing around litchi orchards It may attack.
flower also The female moth lays eggs under Fig 14 4 Rolled leaf. the surface of newly emerged tender leaves,which hatch within 2 8 days The last instar. larvae pupate in larval clip a small portion,of the leaf on the margin both anteriorly and. posteriorly and conceal themselves by bending,and sealing the clipped piece of the leaf Fig. 14 4 and Fig 14 5,The symptoms of leaf injury by the. larvae are manifested through rolling of,tender leaves and feeding inside As a result.
of larval injuries the infested twigs distort and,wither Litchi trees whose foliage is attacked. by the larvae very poor flowering or in Fig 14 5 Leaf roller larva. Insect Pest Management 165, case of younger tree no flowering is seen in the season Thus the crop yield gets reduced. considerably,Management, l The damage caused by leaf rollers is tolerated as long as it is restricted to the foliage and. unlikely to affect flower initiation, l The rolled leaves that contain larvae may be removed manually during light. infestations, l If necessary carbaryl 2g l can be applied when 20 per cent of leaf flushes are infested to.
minimize damage to young trees or at critical periods of leaf growth in older trees. 4 Litchi Fruit Borer, This pest is known as litchi fruit borer or litchi stem end borer or litchi seed borer Fig 14 6 It. is apparently found infesting litchi most often and elicits the greatest economic effects Female. lays eggs singly on the under surface of the leaf or near the calyx of litchi fruits During winter. months the leaf buds are preferred for oviposition. Newly hatched larvae are milky white slender with distinct light brown head The newly. emerged larvae start boring into the fruits and feed on its pulp The infested fruits do not. attain normal size and can be identified by the formation of black spot near pedicel Larvae. do not enter much deeper into the pulp but feed below the calyx about 15mm deep When. fully grown they come out of the fruit and pupate on the leaf surface In this way the larvae. cause direct damage to litchi fruits The full grown larva starts spinning cocoon which is. usually formed on the old litchi leaf, Females clearly prefer fruits over shoots for oviposition If no fruits are available they. are constrained to lay their eggs on shoots The survival rate is higher on shoots than in fruit. During July they cause indirect damage by making mines in young shoots The young larvae. Fig 14 6 Fruit borer in litchi Adult moth left and larvae inset Affected fruits right. 166 A Manual for Litchi Production,PRODUCTION, make mine in the lamina and bore into mid rib of young leaves and tunnel through it as a. result branches wither and drop The pest has now established itself as one of the major pests. of litchi in India particularly in Bihar and Uttar Pradesh. Management, l Moths can be excluded by enclosing the fruit panicles in nylon mesh bags but is. uneconomic in areas with high labour costs, l NRC on Litchi Muzaffarpur has recommended the use of Trichogramma chilonis.
50000eggs ha and use of pheromone trap however this pheromone is not giving. consistent results in all the situations, l Fallen fruit should be removed to reduce the build up of moths and ploughing may be. done after fruit harvesting, l Bearing trees should be inspected during early flush development and sprayed if. necessary The leaf flush before flower initiation is very important as it supplies the. carbohydrates needed for fruit development Young non bearing trees do not need to. be sprayed This also allows the parasitoids to build up in the orchard. l Fruits may be inspected weekly from fruit set to detect eggs of borers which are very. small and almost invisible to the naked eye Infested fruit should be picked and destroyed. at infestation levels of 1 to 2 per cent When the pest becomes more active spraying. 0 05 per cent fenitrothion or dicholorvos or carbaryl 2g l may be done. l Permethrin is applied weekly up to two weeks before harvest Cypermethrin deltamethrin. or fenthion during early fruit set is recommended to prevent damage later in the. l Affected shoots may be removed and all agronomic efforts such as ploughing and. nutrient management should be done so that flushing takes place before the month of. l Neem based products may be applied at the time of new shoot emergence to avoid. heavy population of the pest, l Monocrotophos 0 05 per cent may be applied in the case of severe shoot damage. 5 Shoot Borer, The shoot borer has been observed causing serious damage to new flush of litchi throughout. the country This pest is usually active from August to October Female moths lay eggs on. tender leaves After hatching the larvae first bore into the veins of young leaves and later into. the soft stems of shoots situated close to the apex working their way downwards Fig 14 7. New shoots are damaged by the caterpillars by tunneling from gro. Insect Pest Management 165 case of younger tree no flowering is seen in the season Thus the crop yield gets reduced considerably Management l The damage caused by leaf rollers is tolerated as long as it is restricted to the foliage and unlikely to affect flower initiation

Related Books