Plant Disease Type:
Fungus |
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| This disease
attacks: |
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tomato and potato plants |
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| General Information
about
Early blight : |
Alternaria solani is a fungal pathogen, producing a disease in tomato and potato plants called early blight.
It produces small, darkened lesions on the plants, that spread into growing black spots of dead tissue, often killing most of the plant in the long run. Seeds infected with the disease may even damp off during germination.
This disease can be prevented with some fungicides, including azoxystrobin, potassium bicarbonate, hydrogen dioxide as well as the biological control agent Bacillus subtilis.
Other preventative measures include ensuring the healthy circulation of air in garden rows, rotating crops so that solanaceous plants are only present every three years, and choosing resistant cultivars.
| This plant disease
can commonly be found in these places: |
| How to get rid
of or kill this disease: |
# Use a crop rotation that includes potatoes or tomatoes only every third or fourth year to allow infested plant debris to decompose in the soil. Rotations with small grains, corn or legumes are preferable.
# Use tillage practices such as fall plowing that bury all plant refuse.
# Select cultivars that have a lower susceptibility to early blight.
# Use certified disease-free tomato seed and transplants.
# If producing tomato transplants, disinfest soil in plant beds and control humidity in cold frames or greenhouses. Practice good sanitation throughout the transplant production operation.
# Use appropriate measures to control weeds and volunteer potatoes and tomatoes in production areas.
# Maintain fertility at optimal levels-nitrogen and phosphorus deficiency can increase susceptibility to early blight.
# Time applications of overhead irrigation to allow plants to dry before nightfall.
# Although the above measures are important to minimize infection, it is usually necessary to apply fungicide sprays to fully protect plants from early blight. Applications to tomato are usually begun 2-3 weeks following emergence or soon after transplanting if a calendar schedule is followed. Timing of fungicides can also be made using the TOM-CAST system. For potatoes, fungicide applications should be initiated when plants begin to flower. Thorough coverage is important. Adjust equipment for good vine penetration. For current fungicide recommendations and a description of the TOM-CAST system consult the Ohio Vegetable Production Guide (OSU Extension Bulletin 672).
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