PEACH LEAF CURL

PEACH LEAF CURL

1. PEACH LEAF CURL SUBMITTED BY COURSE TEACHER J.MAHESHKUMAR Dr . S. PARTHASARATHY 2015021073 Asst . Prof. ( PLANT PATHOLOGY)

2. Peach L eaf C url Causal organism: Taphrina deformans Distribution : America, Europe, Asia, Australia, New zealand

3. Systemic Position Kingdom : Fungi Phylum : Ascomycota Class : Taphrinomycetes Order : Taphrinales Family : Taphrinaceae Genus : Taphrina Species : T . deformans

4. Symptoms Diseased leaves can usually be identified soon after they emerge from the bud, due to their red color and twisted shape. As the leaves develop, they become increasingly distorted, and ultimately thick and rubbery compared to normal leaves. The colors of the leaves change from the normal green to red and purple. Fruit may fail to develop from diseased blossoms, or may be affected, showing a reddish colour.

5. Pathogen description Intercellular mycelium devoid of ascocarp . Naked asci are produced individually and bear eight ascospores . Ascospores undergo budding division before released from ascus.

6. Disease cycle   Peach leaf curl is caused by the fungus  Taphrina deformans .  This pathogen is called monocyclic, meaning these fungal spores infect peach leaves only once a year in the spring .   Taphrina  deformans  survive winter on buds or twigs of the tree .

7. Favourable condition For successful infection, the fungus requires cool and wet winters, where rain wets the tree for more than 12.5 hours at temperatures below 16°C (61 °F ).

8. Management The most effective method  is to plant peach trees possibly covered by a mat during the winter, to keep winter rain away from the buds before they burst (incidentally to delay blossoming until spring frosts are over)   Spraying the leaves with fungicides is the most common control method. 

9.   Copper based mixtures (such as  bordeaux mixture) and l ime sulphur are two fungicides commonly used. Peach cultivars can be planted which show some resistance to peach leaf curl, or at least regenerate rapidly, such as Peach ' Benedicte '. No similarly resistant nectarine cultivar is yet known.

10. References:  "Peach--Leaf Curl." An Online Guide to Plant Disease Control. 01 Jan 2008. Oregon State University. 14 Apr 2009 <http:// plant-disease.ippc.orst.edu/disease.