Early Blight
Pathogen: Alternaria solani
Symptoms
The disease first becomes evident in senescent leaves, causing
dark necrotic lesions in a characteristic concentric pattern.
Contamination of the tubers is manifested by dry, dark, round
depressions on the peel.
Damage
Severe infestation results in loss of yield, due to early
leaf death. Dry rot develops on the tubers during storage.
Conditions for Development
Initial infestation is by wind-borne conidia that penetrate
through superficial wounds in the epidermis (such as those
resulting from sand storms or insect damage). Infestation
of the tuber begins during harvest when foliage comes in contact
with the tubers.
Control
Varieties: Most of the early varieties are susceptible;
there are some tolerant varieties.
Pesticides: Use of fungicides protects against the
disease or eliminates it in the field. Recently, systemic
chemicals have been developed.
Management: Avoid irrigating during the hottest hours
and immediately after storms. Avoid harvesting non-mature
tubers. Protect against insect infestations.
Aerial
Stem Rot
Black Dot, Colletotrichum
coccodes
Blackleg and Tuber Soft Rot
Black Scurf, Rhizoctonia Canker
Common Scab, Streptomyces scabies
Early Blight, Alternaria solani
Deep Pitted Scab, Streptomyces spp
Leak, Pythium ultimum
PLRV, Potato Leafroll Virus
Powdery Scab, Spongospora subterranea
PVX, Potato Virus X
PVY, Potato Virus Y
Verticillium Wilt, Verticillium dahliae
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