Rubber diseas

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1. COMMON PESTS & DISEASES OF RUBBER GROUP : E

2. 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.

3. IMPACT OF PESTS AND DISEASES TO THE TREE Damage and defoliate leaves Cause the tapping panel and affect bark renewal Kill branches and trees R oot and stem dieback

4. TO THE ECONOMICS Lengthen the immaturity period Reduce latex yield Increase cost of production Affect the environment

5. LEAF DISEASES Collectotrichum secondary leaf fall Oidium secondary leaf fall Bird’s eye spot Crynecoccum leaf disease Fusicoccum leaf disease Cylindrocladium leaf disease

6. 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

7. Colletotrichum secondary leaf fall Cause – fungus colletotrichum gloesporiode Disease can occur leaves and green parts of plants such as fruits and twigs rubber Factors influence to spread disease : High moisture in the environment Genetic factors

8. 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.

9. 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

10. Corynespora leaf fall Corynespora cassiicola  has been found for the first time in China on Hevea rubber tree. T he 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

11. 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.

12. 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

13. STEM DISEASES Bark necrosis Ustulina stem disease Pink disease

14. 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

15. 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 stresses It 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.

16. PINK DISEASE Causative Agent :- Corticium salmonicolor S ymptoms Pink colour mycelial growth on bark surface with streaks on latex oozing out from the lesions More damaging for plants in the age group of 2 to 12 years M ain seat of infection is usually the fork region Rotting , Drying up and Cracking of the affected bark. Sprout develop from below the affected portion. Clonal Suseptibity :- PB 217 , PB 311 RRII 105 Control Measures Can Use Prophylactic treatment

17. PANEL DISEASES Black strips Mouldy rot Panel necrosis

18. 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

19. 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-

20. 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

21. ROOT DISEASES 1.White Root D isease 2.Red Root Disease 3.Brown Root Disease 4.Purple Root Disease

22. 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

23. 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

24. 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.

25. 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

26. PEST OF RUBBER Termites Slug and snails Mites Mealy bugs Scale insect Bark feeding caterpillar

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

28. 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.

29. Prevention and control Cultural method Mechanical injury to trees Pruning Thinning should be conducted at suitable periods Minimized weeding Biological method Use of entomophagous nematodes Use entomopatogenic fungi Chemical method -Use pesticides Use pheromones Cultivate resistance species

30. 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.

31. MITE ATTACK Causative 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)

32. 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.