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Mite vector
- 1. MITES AS VECTORS OF VIRAL DISEASES OF PLANTS AND THEIR MANAGEMENT HASHIB ANSARI M.Sc. (Ag). Entomology Enrollment no. – GJ 1497
- 2. INTRODUCTION ARTHROPOD-BORNE PLANT VIRUSES: • Arthropod-borne plant viruses are among the most important, complex and extensively distributed plant disease agents in the world. • They are economically important because they serve as vector of plant diseases as well as the intriguing mechanisms by which they survive and propagate.
- 3. ARTHROPODS AND PLANT-VIRUSES THAT THEY TRANSMIT Vector taxa Vector group Icosa- hedral particle s RNA genome Rod shaped particle s RNA DNA genome Enveloped particles RNA genome Total % ACARI Mites 50 1 - - 51 7 HEMIPTE- RA • Aphids • Whitefly • Leafhopper • Planthopper • Other hemipteran 26 - 8 10 153 13 - 4 13 115 15 - 5 - 3 4 197 128 26 18 28 18 4 3 THYSANO PTERA • Thrips 2 - - 14 16 2 COLEOPT- ERA • Beetles 50 1 - - 51 7 NEMATOD A • Nematodes 45 3 - - 48 7
- 4. Vector Taxa Vecto r Grou p Icosa- hedral particle s RNA genome Rod shaped particle s RNA DNA genome Enveloped particles RNA genome Tota l % MYCO TA Fungi 8 16 - - 24 3 No identi fied vecto r 84 60 19 3 166 24 Total 233 268 167 30 697
- 5. CLASSIFICATION OF MITE Phylum : Arthropoda Class : Arachnida Subclass : Acari Order : Trombidiformes Superfamily : Eriophyoidea Family: Eriophyidae
- 6. General characteristics of eriophyid mite Worm like and colorless, greatly reduced cephalothorax. Four pair of legs, modified piercing and sucking mouthpart. They are small, less than 250 micrometre in length . They have no eyes, spiracles or tracheae.
- 7. BIOLOGY OF ERIOPHYID MITE • Developmental stages- • Eggs are laid on host plant but some are ovoviviparous. • Parthenogenesis is suspected but not proved . • Males hatch from unfertilized and females from the fertilized eggs. • Generally two to three weeks are required under ideal condition for completion of life cycle. Egg First and second nymph Adult
- 8. ATTRIBUTES THAT CONTRIBUTE TO THE MITE BEING A SUCCESSFUL VECTOR
- 9. FEEDING HABITS, MECHANISM AND ITS EFFECTS Piercing and sucking action Pharyngeal pump Chelicerae are 15 to 40 micro meter long. Five mouth stylet Two anterior are chelicerae. Two auxillary stylet . One or fifth is oral stylet. Rostrum or gnathosoma Enclosed by pedipalps which hold slender mouth stylet and have telescopic movement.
- 10. MODE OF TRANSMISSION • Mode of transmission of virus varies with the host plant and pathogen carried by the vector according to the different experiments conducted on vector- virus relations.
- 12. • If virus is acquired by the nymph then only adult can transmit the virus. • Mites has small stylet therefore superficial epidermis is penetrated that reveal non-persistant manner of transmission but also in circulative manner because acquisition feeding period is long and virus also retain after moulting. • They transmit the virus in non-persistant and circulative manner e.g. WSMV.
- 13. OTHER MEANS OF TRANSMISSION OF DIFFERENT VIRUSES • Currant reversion virus Infect only woody • Fig mosaic virus plants and • Peach mosaic virus artificial by grafting. • Wheat streak mosaic virus Infect only grasses • Wheat spot mosaic virus and manual • Ryegrass mosaic virus by rubbing.
- 14. Currant reversion virus(CRV) • Transmitted by Cecidophyosis ribis . • First evidence given by (Amos et al. 1927). • Masses 1952 confirmed the transmission by mites. • Symptom : characteristic change of leaves and bushes.
- 15. Wheat streak mosaic virus(WSMV) • Transmitted by Aceria tulipae. • First reported in kansas 1932. • Serious and widely distributed disease of winter wheat. • Also occur on spring wheat and barley, corn , rye, oats and a number of annual and perrenial grasses. • Damage to winter wheat is most severe.
- 16. WSMV SYMPTOMS
- 17. SYMPTOMS
- 19. WSMV DISEASE CYCLE WSMV is transmitted from plant to plant by all nymphal stages of mite. Mite feed on upper and near the leaf margin causing the leaf edges to curl tightly. The mite develop into adult 8 to 10 days and it is non transovarial transmission. Acquisition feeding period -15 minutes, Persistence - 7 to 9 days without additional acquisitions.
- 20. WHEAT SPOT MOSAIC VIRUS (WSpMV) • Transmitted by Aceria tulipae. • Aceria tulipae proved as vector in 1956 by Slykuis. • Frequently associated with WSMV. • Chlorotic spots on the leaves. • Except egg stage all the stage can transmit the virus.
- 21. FIG MOSAIC VIRUS(FMV) • Transmitted by Aceria ficus. • Different pattern of chlorotic to yellowish mottling and deformation of leaves. • Leaves and fruits may be dwarfed and some leaves may be malformed. • On leaves, mosaic spots will appaear yellow and may cover large areas of leaves. • In some cultivars, premature defoliation and fruit drop can occur.
- 22. SYMPTOMS OF FMV
- 23. PIGEONPEA STERILITY MOSAIC VIRUS (PPSMV) • In India first reported by Mitra in 1931 from Pusa Bihar. • Inhibit flower production and renders plant sterile. • Early infection leads to complete sterility. • In later stages sterility in some branches only. • In northern Karnataka, about 20 per cent of the gross pieonpea production, worth of $11 million per annum was lost due to SMD.(Dharmaraj et al., 2004)
- 24. MODE OF ACTION • In nature the causal agent of SMD is transmitted by the eriophyid mite Aceria cajani ChannaBasavanna (Seth, 1962). • PPSMV are transmitted in semi-persitant manner. • The PPSMV genome contains five segments of single- stranded RNA . • The Aceria cajani mites acquires PPSMV after a minimum acquisition access period (AAP) of 15 minute. • Minimum inoculation access period (IAP) is 90 minute.
- 25. SYMPTOMS
- 26. OTHER PLANT DISEASES TRANSMITTED THROUGH MITES • Rye grass mosaic : Abacarus hystrix. • Fig mosaic : Eriophyes ficus • Peach mosaic : Phytoptus insidiosus • Mango malformation : Eriophyes mangiferae • Cherry mottle leaf : Phytoptus inaequalis • Wheat spot mosaic : Aceria tulipae.
- 27. MANAGEMENT • BIOLOGICAL CONTROL- • Entomopathogenic fungus like Beauveria bassiana or Hirsutella thompsoni is also effective in PPSMV @ 1 x 𝟏𝟎 𝟕 conidia/ ml of water. • Predatory mite Agistemus exsertus, spiders and coccinellids manage the population of eriophyid mite. • CULTURAL PRACTICES - • Use resistant variety ICP 10979 and ICP 87119 to PPSMV and RonL,WSM1, Millenium, Pronghorn for WSMV. • Destroy alternate host Cajanus scarabaeoides.
- 28. BIOTECHNOLOGICAL APPROACH- • Source of resistance to WSMV and the vector can be performed by breeding programs in Triticum- Agropyron chromosome substitution lines. CHEMICAL CONTROL- • Spray 4-5% NSKE after 20 to 25 days after sowing. • Spray acaricides such as kelthane @ 1 ml per litre of water at maturity stage. • Foliar spray of karathane @ 0.1%. • Foliar spray of dimecron @ 0.04%.
- 29. CONCLUSION • Mite transmits viruses in non-persistant, semi- persistant and in circulative manner. • Use of resistant cultivar is most viable tactics. • There is a long way to go for this novel viruses to be thoroughly understood in terms of its diversity in the Indian subcontinent, it’s vectors and ultimately, the delivery of disease-resistant cultivars to the poor and marginal farmers of South-East Asia.
- 30. • Community based ecological approaches should be recommended for success in managing mites population. • Acaricides are not found efficacious in reducing population of mites as alternative bio control agents should be conserved and promoted among farmers community. • Removal of alternate host such as weeds results in breaking the development of it’s inoculum.