Eyespot

Pseudocercosporella herpotichoides

Damage
Eyespot usually becomes visible in early spring as diffuse brown smudgy areas on the lower leaf sheaths. They develop into characteristic ellipsoid eyespot symptoms on the stem base. Lesions become more defined when the pathogen penetrates the stem and may produce an eye-shaped lesion with a 'pupil' of black dots. Severe infections cause weakening of the stem and lodging at the lesion.
In contrast to lodging from wind, which often is unidirectional, diseased plants tend to lodge in all directions (straggling). Under dry conditions without lodging, severely affected shoots tend to ripen prematurely producing shrivelled grain with low kernel weight. Under moist conditions white heads become colonized by sooty molds and turn to a black appearance.
Infection can occur soon after seedling emergence and may kill the plants when attacks are severe. Severe infection of stems is categorized as where half or more of the circumference of the stem is affected by a lesion causing weakening such that lodging could occur and moderate infection is a half or more of the stem circumference affected by a lesion; when lesions affect less than half the outer sheaths infection is rated slight.

Cause
Being poor competitors in the soil Helgardia spp. survive on cereal stubble; in addition some grass and weed species may also serve as inoculum source.

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