rubber diseas

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Oidium secondary leaf fall

COMMON PESTS & DISEASES OF RUBBERGROUP : E

Rubber - Hevea brasiliensis

the important plantation crops in srilanka.

The rubber tree is affected by a number of diseases of economic important and they can be divided for convenience into four categories.

As well as pest attack also harmful to rubber plant.

IMPACT OF PESTS AND DISEASES

TO THE TREE

Damage and defoliate leavesCause the tapping panel and affect bark renewalKill branches and trees Root and stem dieback

TO THE ECONOMICSLengthen the immaturity periodReduce latex yield Increase cost of productionAffect the environment

LEAF DISEASES

Collectotrichum secondary leaf fallOidium secondary leaf fallBirds eye spotCrynecoccum leaf diseaseFusicoccum leaf diseaseCylindrocladium leaf disease

Oidium secondary leaf fall

Fungus oidium heveae (powdery mildew)Infects mostly to young shoots that refoliate after winteringSign of attack is presence of numerous leaflets on the ground.Symptoms leaf defoliation young leaves cover with powdery massesEffect -reduces latex yield

Colletotrichum secondary leaf fallCause fungus colletotrichum gloesporiodeDisease can occur leaves and green parts of plants such as fruits and twigs rubberFactors influence to spread disease : High moisture in the environment Genetic factors

Symptoms On young leaves : blackish brown splotches in the leaf middle leaf blade wrinkled wet rot incidence in affected area leaf fallOn old leaves : brown splotches with halo yellow leaf becomes rough surface further attacks cause the patches to be perforate On young twigs : rot, dry and eventually die back.

Disease spread through spores.Wind, dew or rain water move the spores.

Birds Eye SpotCausative Agent : Drechsiera heveae (Fetch) M.B. EllisOccurrence : A hot weather disease serious & damage in the nursery : Weaker plants & plants growing under exposed situationsSymptoms : Small necrotic spots with dark/brown margin & pale centre : Premature defoliation & Die back

Corynespora leaf fallCorynespora cassiicolahas been found for the first time in China on Hevea rubber tree.The most important leaf disease of rubber in AsiaCaused by Fungus Corynespora cassiicolaRole of cassiicolin, a host-selective toxin, in pathogenicity ofCorynespora cassiicola, causal agent of a leaf fall disease ofHevea.Cameroon, India, Indonesia, Malaysia, Sri Lanka and Vietnam

Mainly confined to the nurseries and young immature plants in main fieldSymptoms on leaves included fishbone necrosis and spots or characteristic railway track symptoms.Infects young and old leaves.Causes leaf fall, shoot dieback.Increase immaturity period, reduces yield.Kills plants.

Control measures.

Technical methods (indirect preventive methods)plant resistant clones.Improve the plant conditions (fertilization , sanitation,drainage,reduce the frequency of tapping)Chemical methodsUse of fungicides. Dusting the leaves with sculpture thought the refoliating season at 5 to 6 weekly round.

Fogging with fungicide tridemorph such as calixin 75 EC at 0.5 a.i/ha

STEM DISEASES

Bark necrosis Ustulina stem diseasePink disease

DRY ROT (Ustulina Stem Rot) caused by Ustulina deusta. observed near the collar region, on the main trunk of even on the branches during the rainy season. The symptom appears as exudation of latex. Later fruiting bodies of the fungus appear as soft circular to irregular, grayish white ear lobe like structures which later join together and became grey or black and brittle . The fungus penetrates the wood and spreads inside. As a result the wood becomes soft and the trees breakdown. Black double lines formed by the fungus are seen inside the wood. The fungus penetrate the bark through wounds and cracks and hence the disease incidence is more following heavy wind

BARK NECROSIS(BN)The necrosis of the rubber tree is an affection of the stem. It is expressed by a deterioration of the cortical tissues on the level of which are located in the conducting latex tissues.starting right at the grafting point situated in the transition zone between the trunk and the roots, the collar.It is leading to the cessation of latex production, showed differences in latex biochemical characteristics, attacks the tree vascular tissues.the rubber trees hit by necrosis have poorer than normal root development.causative pathogen for BN has not found, but showed that BN is favored by a combination of various stressesIt results from the accumulation of climatic and human-induced stresses and physiological malfunctions in the grafted trees.Chemical and biological methods can use for control this disease.

PINK DISEASECausative Agent :- Corticium salmonicolorSymptoms Pink colour mycelial growth on bark surface with streaks on latex oozing out from the lesionsMore damaging for plants in the age group of 2 to 12 years Main seat of infection is usually the fork regionRotting , Drying up and Cracking of the affected bark. Sprout develop from below the affected portion.

Clonal Suseptibity:- PB 217 , PB 311 RRII 105Control Measures Can Use Prophylactic treatment

PANEL DISEASES

Black stripsMouldy rotPanel necrosis

Phytophthra palmivoraP. meadii

BLACK STRIPE DISEASEAGENTOCCURSYMPTOM

. Renewed bark region

Small depression are formed due to localized rotting .During of bark which gets pressed to the wood

When scraped vertical blank line running downward into tapping bark & upward into the renew barked

Reduce yield

Renew bark highly uneven During the rainy season

Ceratocystis fimbriata attacks the tapping panel

Causing a pale-grey mould on the surface of the panel and dark discoloration in the wood under the surface.

Affect- Commonly in high moisture and weedy conditions especially on panels reaching the ground

Mouldy rot of rubber-

Tapping is regularly done during rainy season Tapping panel should be disinfected at weekly intervals by brushing.

Chemical control of panel diseases- Fungicides can be used to treat tapping panels

Appling fungicide in two method- Spraying of fungicides using hand held sprayers Painting with brushCONTROL of panel diseases

ROOT DISEASES1.White Root Disease2.Red Root Disease 3.Brown Root Disease4.Purple Root Disease

White Root Rot DiseaseInfective fungal organism: Rigidoporus lignosusSymptoms : root infection, colonization within the taproot & other parts of the root. : foliage discoloration : tree branches die back : tree eventually dies

Causative agent is Phellinus noxiusThat disease occurrence often in replanted area & sandy or light soils.

SYMPTOMSGrowth retardationGeneral yellowish discoloration of the foliageHoneycomb structrure on wood surface & inside woodA layer of soil/sand with brown spots BROWN ROOT DISEASE

Purple Root Disease

The occurrence of purple root disease caused by Helicobasidium compactum is reported for the first time on Hevea brasiliensis in India .

Infection on nursery plants , occasionally leading to their mortality.

Disease symptom.Purple- colored fungal growth on the root surface. Adventitious root formation.The presence of distinct fruiting bodies girdling the collar region.

CONTROL OF ROOT DISEASES

Pre planting correct land clear procedure.During planting S application & planting creeping legume as cover plant. Immature rubber chemical control. Mature rubber isolation trench. Completely killed & dried root , prune off & burnt Dried plants should be uprooted & destroyed Apply fungicide by painting or drenching

PEST OF RUBBER

TermitesSlug and snailsMitesMealy bugsScale insectBark feeding caterpillar

TERMITES ATTACK

Damage by Coptotermes curvignathus .Attack can be above ground level . The infestation is usually internal and may occur through the roots.

SymptomsMainly occur in mature plant.It occur a early stage of growth.A layer of mud on the surface of trunk.The bark texture become fissured and roughReduce the value of timber.Leaves are yellowing and wilting.At an advanced stage the leaves turn brown and fall off.Finally tree will die.The bark can be seen to be riddled with holes.

Prevention and controlCultural methodMechanical injury to treesPruningThinning should be conducted at suitable periodsMinimized weedingBiological methodUse of entomophagous nematodesUse entomopatogenic fungiChemical method-Use pesticidesUse pheromonesCultivate resistance species

SLUG AND SNAIL ATTACK Slug and snail Randomly distributed in rubber cultivated areaMain Symptoms areFeed on latex by lacerating the tender leaves and buds.Growth of affected buds is arrested and side shoots develop giving a bunchy appearance. Slugs drink latex from the tapping cut and collecting cup also. Clonal Susceptibility: Nursery seedlings are more susceptibleControl Measures: Broadcast 2.5%