Net Blotch
Pyrenophora teres
Pathogen
Fungus
Hosts
Barley
Symptoms
The first symptoms are very small, dark brown lesions on the leaves. These develop into short brown stripes or irregular blotches which, on close examination, are seen to consist of a network of brown lines. The ear can also be infected but lesions do not usually appear.
Development
The disease can arise from infected seed but the main source of inoculum is infected stubble and volunteer plants. The disease spread by airborne spores and rain splash.
Favourable Factors
Cool, wet and humid weather favours this disease as do thick sowing, early drilling and minimal cultivation techniques.
Importance
Yield losses from 10% to 40% with a reduction in thousand grain weight.
Control
Correct application of fungicides during autumn and/or spring will give good control.
Stubble cleanliness helps to reduce the potential inoculum for infection.
Varietal resistance should also be considered.
