Diseases/ Pests

Symptoms and damage

Managements

Damping off

Rhizoctonia solani

Brown necrotic spots and girdling on the radicle, later on extends to plumule and causes pre-emergence mortality.

Infected seedlings are pulled, sterilization of soil with Formalin@ 2% or Captan 2g/ litre of water.

Leaf spot and blight

Alternaria sp., Septoria sp., Cercospora sp.

The minute brown circular and brownish-grey spots appear on the leaves.

Spraying fungicides regularly.

Collar and root rot

Pellicularia filamentosa, Pythium ultimum, Sclerotinia slerotiarum

Rotting of root and collar portions is noticed in nursery stage which resulting in wilting of the plant.

Soil sterilization and controlled watering.

Flower bud rot 

Alternaria dianthi

Buds are shriveled, turn dark brown and dry up. Symptoms are less prominent on matured buds but these buds also fail to open.

Spraying Dithane M- 45 and Ridomil @ 2.5g/lit of water.

Bud caterpillars

Helicoverpa armigera and Phycita sp.

Eggs are laid singly on young buds. Larvae feed on developing flowers by damaging florets. Larvae of Phycita sp. feed on heads of buds and flowers.

Collection and destruction of infested buds and flowers.

Aphids

Aphis gossypii

Aphids mainly infest lower surface of flowers and base of petals. Nymphs and adults suck the sap from the flowers causing discolouration and withering.

 2-3 sprays of Imidachloropid solution 0.25%.