PATH 372 Diseases of Horticultural Crops
PATH 372 Diseases of Horticultural Crops
PATH 372 Diseases of Horticultural Crops
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Management<br />
All collateral hosts in the vicinity should be destroyed before planting new crop<br />
Rouge out and destroy diseased plants<br />
Virus free seed should be obtained and used for sowing<br />
Soak the seeds in 10% Tri-sodium orthophosphate for 15 to 20 minutes prior to<br />
sowing<br />
Heat treatment for 2-4 days at 70 0 C<br />
Cross protection <strong>of</strong> tomato seedlings by inoculating with mild strains<br />
Field workers should avoid using tobacco products while working in the field<br />
6) Bacterial fruit canker: Clavibacter michiganense subsp. michiganense<br />
Symptoms<br />
Disease appears as spots on leaves, stems and fruits and as wilting <strong>of</strong> leaves and<br />
shoots<br />
White blister like spots in the margins <strong>of</strong> leaves<br />
Spots become brown with age and coalesce, but do not fall <strong>of</strong>f<br />
Leaves wilt and curl upward<br />
Light coloured streaks on stems and petioles at the joints<br />
Cracks develop in streaks and form cankers<br />
Slimy bacterial ooze through the cracks in humid weather<br />
Small, shallow, water soaked, white spots on fruits<br />
The centers <strong>of</strong> white spots become slightly raised, tan coloured and rough<br />
Birds eye like appearance <strong>of</strong> spots, which have brownish centers and white halos<br />
Vascular discolouration<br />
Large cavities in pith and cortex which extend to outer surface <strong>of</strong> stem and cause<br />
cankers<br />
Survival and spread<br />
Survive in or on seeds and on plant debris in soil<br />
Spreads through the seed and Solanaceous weeds such as Solanum nigrum<br />
Epidemiology<br />
Soil temperature <strong>of</strong> 28 0 C and humid weather<br />
Management<br />
Extraction <strong>of</strong> seed through fermentation <strong>of</strong> pulp at room temperature for 72 hours<br />
eradicates the bacterium from the seed.<br />
Hot water treatment <strong>of</strong> seed at 52 0 C<br />
Three year crop rotation<br />
Protective sprays with COC and streptomycin sulphate<br />
Soil solarization<br />
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