DISEASES OF VEGETABLE TYPES

Описание: DISEASES OF VEGETABLE TYPES
FUSARIUM WILT
Causal Organism: Fusarium oxysporum f.sp.capsici
Sub-division: Deuteromycotina
Symptom: Disease symptoms are characterised by an initial slight yellowing of the foliage
and wilting of the upper leaves that progress in a few days into a permanent wilt with the
leaves still attached.
Fig 18.2: Wilt of chilli
Disease cycle:
Primary Infection: Chlamydospores
Secondary Infection: Conidia
Favourable condition:
Acidic or light textured soils with poor drainage facility increase disease incidence.Management:
 Use of wilt resistant varieties.
 Drenching the soil with 1% Bordeaux mixture.
 Seed treatment with 4g Trichoderma viride formulation or 2g Carbendazim per kg
seed is effective.
 Mix 2kg T. viride formulation mixed with 50kg FYM, sprinkle water and cover with a
thin polythene sheet. When mycelia growth is visible on the heap after 15 days, apply
the mixture in rows of chilli in an area of one acre.
64
18.3 CHILLI LEAF CURL
Causal Organism: Chilli leaf curl virus
Symptom: Leaves curl towards midrib and become deformed. Stunted plant growth due to
shortened internodes and leaves greatly reduced in size. Flower buds abscise before attaining
full size and anthers do not contain pollen grains.
Fig 18.3: Leaf curl of chilli
Disease cycle:
Primary Infection: Diseased wild and chilli plant
Secondary Infection: Insect vector white fly
Favourable condition: High humidity, mild temperature, low wind speed
Management:
 Spray dimethoate @0.2% to control the vector.
 Grow resistant varieties.
 Uproot the disease plant.
65
session19
DISEASES OF TURMERIC
19.1 LEAF SPOT OF TURMERIC
Causal organism: Colletotrichum capsici
Sub-division: Deuteromycotina
Symptom:
On leaves, elliptic to oblong spots appear on both the surfaces, but more on upper surface.
Mature spots have grayish center with dark brown margins surrounded by a yellow halo.
Central portion of the spot becomes thin and papery. Several spots coalesce to form irregular
necrotic patches.
Fig 19.1: Leaf Spot of Turmeric
Disease cycle
Primary Infection: Infected plant debris
Secondary Infection: Air borne conidia
Favourable condition:
Cool and humid weather favours the disease development
Management
 Remove and destroy infected plant debris
 Treat rhizomes with Copper [email protected]% solution
 Spray Carbendazim + [email protected]% during Aug-Dec .
 Avoid excess shading
 Tolerant varieties: TS-2, TS-4, TS-9, TS-8.
66
DISEASES OF CORIANDER
20.1 STEM GALL OF CORIANDER
Causal organism: Protomyces macrospores
Sub-division: Ascomycotina
Symptoms
Galls appear on the leaves and stems of the plants affected by this disease. Shape of
coriander seeds change due to effect of the disease.
Fig 20.1: Stem gall of Coriander
Disease cycle:
Primary Infection: Chlamydospores.
Secondary Infection: Conidia
Favourable condition:
 Minimum/maximum atmospheric temperature and relative humidity plays an
important role in the initiation and development of this disease.
 Potassium and nitrogen fertilizers reduced stem gall incidence while phosphorus
fertilizers increased it. pH of 7.5 was most suitable for infection while minimum
infection occurred at pH .
Management:
 The disease affects less in the early and late sown crops.
 Sowing crop around 16 October and 16 November gave minimum yield losses.
 Use of clean and healthy seed and follow suitable crop rotation.
Use resistant cvs./ lines like JD 1, G-5365-91, Pant Haritma, UD 20, Rcr41,Pant
1,CIMAP-2053.
 Seed treatment with Carboxin + Thiram 2g/kg of seeds followed by their foliar sprays
were found effective in managing this disease.
67Management:
 Use of wilt resistant varieties.
 Drenching the soil with 1% Bordeaux mixture.
 Seed treatment with 4g Trichoderma viride formulation or 2g Carbendazim per kg
seed is effective.
 Mix 2kg T. viride formulation mixed with 50kg FYM, sprinkle water and cover with a
thin polythene sheet. When mycelia growth is visible on the heap after 15 days, apply
the mixture in rows of chilli in an area of one acre.
64
18.3 CHILLI LEAF CURL
Causal Organism: Chilli leaf curl virus
Symptom: Leaves curl towards midrib and become deformed. Stunted plant growth due to
shortened internodes and leaves greatly reduced in size. Flower buds abscise before attaining
full size and anthers do not contain pollen grains.
Fig 18.3: Leaf curl of chilli
Disease cycle:
Primary Infection: Diseased wild and chilli plant
Secondary Infection: Insect vector white fly
Favourable condition: High humidity, mild temperature, low wind speed
Management:
 Spray dimethoate @0.2% to control the vector.
 Grow resistant varieties.
 Uproot the disease plant.