Fungal diseases of vegetables-Cabbage

1. Fungal diseases of vegetables-
Cabbage
Vaishali S.Patil
Professor, Department of Botany
Shri Shivaji College of Arts, Commerce & Science
Akola

2. 1.Wirestem caused by Rhizoctonia solani
Symptoms- Constriction occurs at the base of the stem on the
seedling which progresses upwards giving the plant a wire-
like appearance. Affected plants remain stunted or may
break off at ground level. Plants affected soon after
transplanting usually die. Seedlings that have suffered
mechanical injury from transplanting operations, wind
damage or insect attack are vulnerable to infection(Root
rot)("damping-off").The plant becomes weak. It shows
stunted growth and smaller heads.
Control: Use certified disease-free transplants.

3. 2.Fusarium yellows caused by Fusarium oxysporum
Symptoms- Leaf yellowing, defoliation of older plants,
stunting and death of seedlings. Stems are often twisted to one
side. It also cause a curve in the midrib, resulting in a plant
that is stunted to one side.
Control: use yellows-resistant varieties

4. 3.Blackleg caused by Leptosphaeria maculans/ Phoma
lingam
Symptoms-Stem damage can lead to cankering and severing
of the plant at the base. The lesions are light brown with a
purplish outline which often contain pinhead-sized, black dots.
The lesions tend to be linear and irregularly distributed.
Control: Use certified disease-free seed and transplants, treat
seed with hot water, choose varieties tolerant, Select well-
drained sites with good air circulation, Good sanitation
practices, not handling plants when they are wet.

5. 4. Leaf spot/target spot caused by Alternaria brassicae &
A. brassicicola
Symptoms- The circular leaf spots vary from mid to dark
brown to black. The spots often have a target-like appearance
as a yellow halo surrounds the sunken centre, as well as
affecting the leaf. It can cause blackening of curds. dark leaf
spots in affected plants. They are both seedborne and airborne.
Control: Remove and destroy all crop debris, seed treatment
and rotation, fungicides.

6. 5.Clubroot caused by Plasmodiophora brassicae
Symptoms- Clubroot causes galls to form on roots of infected
plantsi.e. swellings. The galls interfere with the plant’s uptake
of water and nutrients. Under warm conditions, plants often
wilt which is usually the first sign of clubroot infection. The
death of seedlings takes place. Wilting plants should be
removed from the ground to check for galls on the roots.
Leaves become stunted, yellowish and prematurely bolt.
Control: use only uninfected seedbeds and clean equipment.
Long rotations, use of susceptible varieties.

7. 6.Damping off caused by Fusarium or Pythium sp.
Symptoms- Obvious signs are missing plants or wilting of
newly-emerged seedlings. There may be a wet rot of the stem
and seedling stems may become constricted. These fungi are
soil-borne and survive in soil without a host being present.
Control: Planting on raised beds and providing good
drainage. Start seeds in commercial potting soil, not in garden
soil use of biocontrol fungicide.

8. 7.Downy mildew caused by Peronospora parasitica
Symptoms- Leaf symptoms appear as yellowish, irregular
areas on the upper surface corresponding to a white fluffy
growth on the undersides of leaves. Older lesions become dry,
brown and papery in texture and may cause the entire leaf to
drop and curds may be infected with black spots within or on
the surface.
Control: Use varieties with resistance or tolerance, crop
rotation, remove plant debris, use wide plant spacing, avoid
wetting the leaves, fungicides.

9. 8.Powdery mildew caused by Erysiphe cruciferarum
Symptoms- white lesions on the top of the leaves,produces a
white powdery mould on the top surface of leaves.
Control: Fungicides, resistant varieties, avoid drought stress,
don’t use too much nitrogen fertilizer.

10. 9.White blister caused by Albugo candida
Symptoms- White blisters form on the undersides of leaves,
with a corresponding yellow patch on the upper surface. It can
cause distortion of the plant stem as well as formation of galls
on leaves.
Control: Use of resistant varieties, fungicides, crop rotation.

11. 10.Ring spot caused by Mycosphaerella brassicicola
Symptoms- lesions are grey and contain black, pinheads dots
in concentric rings. Severe ring spot on leaves can reduce
growth, delaying harvest and damaging crops that are
harvested in leaf.
Control: treat seeds with hot water prior to planting,
fungicide, removing infected plants and destroying all crop
debris.

12. 11.White mould/ Sclerotinia rot caused by
Sclerotinia sclerotiorum, Sclerotinia minor.
Symptoms-water-soaked areas which later become covered by
a fluffy white mould. At the late stage of infection, black
sclerotes about the size of rice grains may be seen in the white
mould or inside the stem of the plant.
Control: restrict air circulation, Mechanical injuries should be
avoided, crop rotation.

13. 12.Bottom rot caused by Rhizoctonia solani
Symptoms-Tan or brown lesions on the outer leaves. Then the
fungus invades the center of the head, which can rot
completely within 10 days.
Control: Planting in raised beds will help to protect crop,
keeping crop healthy and providing the proper amount of
fertilizer.

14. 13.Phytophthora root rot caused by Phytophthora
megasperma
Symptoms-Discoloration of the margins of the leaves,
changing to red and purple as the roots die. As symptoms
progress to the stem, the leaves die back. Plants that are
infected generally wilt and frequently die.
Control: soil drainage, rotate, soil treatments, fungicides.