COMMON PESTS & DISEASES OF
RUBBER
GROUP : 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 leaves Cause the tapping panel and affect bark
renewal Kill branches and trees Root and stem dieback
TO THE ECONOMICS
Lengthen the immaturity period
Reduce latex yield Increase cost of
productionAffect the environment
LEAF DISEASES
Collectotrichum secondary leaf fall
Oidium secondary leaf fall Bird’s eye spot Crynecoccum leaf disease Fusicoccum leaf disease Cylindrocladium leaf
disease
Oidium secondary leaf fall• Fungus – oidium heveae (powdery mildew)• Infects mostly to young shoots that refoliate after wintering• Sign of attack is presence of numerous leaflets on the
ground.• Symptoms – leaf defoliation young leaves cover with powdery masses• Effect - reduces latex yield
Colletotrichum secondary leaf fall
Cause – 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 fall On 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.
Bird’s Eye Spot• Causative Agent : Drechsiera heveae (Fetch) M.B. Ellis• Occurrence : A hot weather disease serious & damage in the nursery : Weaker plants & plants growing under exposed situations• Symptoms : Small necrotic spots with dark/brown margin & pale centre : Premature defoliation & Die back
Corynespora leaf fall
• Corynespora cassiicola has been found for the first time in China on Hevea rubber tree.
• The most important leaf disease of rubber in Asia
• Caused by Fungus Corynespora cassiicola• Role of cassiicolin, a host-selective toxin, in
pathogenicity of Corynespora cassiicola, causal agent of a leaf fall disease of Hevea.
• Cameroon, India, Indonesia, Malaysia, Sri Lanka and Vietnam
• Mainly confined to the nurseries and young immature plants in main field
• Symptoms 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 methods Use 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
disease• Pink 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 strips
Mouldy rot Panel
necrosis
• Phytophthra palmivora• P. meadii
BLACK STRIPE DISEASE
AGENT
OCCUR
SYMPTOM•. 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 brush
CONTROL of panel diseases
ROOT DISEASES
1.White Root Disease2.Red Root Disease 3.Brown Root Disease4.Purple Root Disease
White Root Rot Disease
• Infective fungal organism: Rigidoporus lignosus
• Symptoms :
root infection, colonization within the taproot & other parts of the root. : foliage discoloration : tree branches die back : tree eventually dies
Causative agent is Phellinus noxius That disease occurrence often in replanted area & sandy or light soils.
SYMPTOMS• Growth retardation• General yellowish discoloration of the foliage• Honeycomb structrure on wood surface & inside wood• A layer of soil/sand with brown spots
BROWN ROOT DISEASE
Purple Root DiseaseThe 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
Termites Slug and snails Mites Mealy bugs Scale insect Bark 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.
Symptoms• Mainly 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 rough• Reduce 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 control• Cultural method1. Mechanical injury to trees2. Pruning3. Thinning should be conducted at suitable periods4. Minimized weeding• Biological method1. Use of entomophagous nematodes2. Use entomopatogenic fungi• Chemical method
-Use pesticides• Use pheromones• Cultivate resistance species
SLUG AND SNAIL ATTACK • Slug and snail Randomly distributed in rubber cultivated area• Main Symptoms are
Feed 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 susceptible• Control Measures: Broadcast 2.5% Metaldehyde bait pellets
(snail kill 2.5) at the base of the infested plants or seedling beds
• Physical barriers: scatter crushed egg shells, sawdust or wood shavings around plants at risk.
MITE ATTACKCausative Agent: Hemitarsonemus dorsalis.Occurrence: Sporadic incidence on young rubber plants in
nurseries.Symptoms: Not a serious pest. Minute organisms with four pairs of legs. Suck sap from the leaves resulting in
crinkling and shedding.Clonal Susceptibility: Clones like PB 217,RRII 105 and
RRIM 600 are susceptible.Control Measures: Dust sulphur or spray sulphur 0.2%
(Sulfex 80 WP 2.5g/L)Dicofol 0.05%(Kelthane 18 EC 3ml/L)
SCALE INSECTS ATTACK • Scientific name - Coccoidea
• SCALES are limpet like insects that feed by sucking sap from a rubber plants. Scale insect can weaken plants and some excrete sticky substance (like honeydew ) on foliage ,which allows the growth of black,sooty molds.
• CONTROL MEASURES - insects prune and dispose of infected branches, twigs and leaves or hit product protects against common insect attacks.