Atlantic Forage Guide - Perennia

COMMON DISEASES
All forage legumes and grasses grown in the Atlantic region are susceptible to disease. Disease
prevalence depends on many factors, including the presence of sources of infection and
favourable temperature and moisture conditions.
Legume diseases
Many diseases affect more than one forage legume crop. In the Atlantic region, root and crown
rots, common leaf spot, black stem, downy mildew, powdery mildew, northern anthracnose,
sooty blotch, clover phyllody, and nematode diseases have been identified in a variety of
legumes.
Verticillium wilt of alfalfa has been identified throughout Atlantic Canada. Verticillium wilt is a
serious disease because it can reduce alfalfa plant populations to the extent that forage quality and
quantity is severely affected. Verticillium wilt is spread by sowing contaminated seed or by
carrying infected plant parts from one field to another on harvesting equipment. Long-term
control can be achieved by using alfalfa cultivars that show resistance to the effects of the
verticillium organism. Highly-resistant cultivars recommended for use in the Atlantic Provinces
are provided in the annual, Forage Guide to Variety & Mixture Selection.
Grass diseases
Common diseases that affect Atlantic forage crops include leaf rust brown stripe, eyespot, and
brown spot. Each disease is caused by a different organism. Symptoms include decaying roots,
spots on the stems and leaves, and leaves replacing flower petals.
Prevention is the best method of disease control; chemical control methods are seldom necessary.
Good farm practices, such as using resistant or tolerant cultivars, crop rotation, and using early
cutting management, will reduce the incidence of disease. In terms of farm management, delayed
cutting is the factor most responsible in the build-up of disease.
CROP MANAGEMENT
Harvest management
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