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PATH 372 Diseases of Horticultural Crops

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1) Blotch – Septoria chrysanthemella<br />

DISEASES OF CHRYSANTHEMUM<br />

Symptoms<br />

Blackish brown circular to irregular spots on leaves which later form large patches<br />

covering major portion <strong>of</strong> the leaf<br />

Patches are surrounded by chlorotic halo<br />

Later the centers turn greyish and the leaves remain small and curl<br />

Dead leaves hang on stem for some time<br />

Dead leaves hang on stem for some time<br />

Survival and spread<br />

P.I: Infected plant debris in soil<br />

S.I: Wind borne conidia<br />

Management<br />

Collect and burn diseased plant material<br />

Spray carbendazim@0.1%<br />

Tolerant varieties: Alpana, Sarad and flirt<br />

2) Chrysanthemum stunt - Viroid<br />

Symptoms<br />

Small plants with paler plants and flowers<br />

Some flowers appear bleached and are inferior in quality<br />

Flowers from diseased plants open 7 t0 10 days earlier than healthy ones<br />

Axillary buds grow prematurely and produce number <strong>of</strong> branches and stolons and<br />

plants are stunted in appearance<br />

White specks and yellow blotches appear on leaves <strong>of</strong> some varieties<br />

Cuttings from diseased plants root poorly<br />

Survival and spread<br />

P.I: Viroid survives in infected plants<br />

S.I: Spread through sap and knives or tools used during pruning or pinching plants,<br />

taking cuttings and cutting the flowers<br />

Management<br />

Use certified Viroid free stocks<br />

Remove and destroy infected plants<br />

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