Cerall
General
Foot rot of cereals, caused by the fungal pathogen Microdochium nivale (formerly known as Monographella nivalis), is a significant concern for cereal crop growers worldwide. This disease primarily affects the roots and lower stem of cereal plants, leading to rotting and ultimately compromising plant health and yield. Microdochium nivale thrives in cool, moist conditions, making it particularly problematic in temperate regions.
Life cycle and appearance of Foot rot of cereals
Microdochium nivale, a fungal pathogen responsible for causing foot rot in cereals, has a lifecycle showing complex interactions with environmental conditions and host plant physiology. Typically, the lifecycle begins with the release of spores from infected plant debris or soil. These spores, known as conidia, are spread by wind, water, or human activity to susceptible plant tissues. Upon encountering favorable conditions, such as cool temperatures and high humidity, the conidia germinate and penetrate the host's tissues. Inside the plant, the fungus colonizes the root and lower stem, leading to the characteristic symptoms of foot rot. As the disease progresses, the fungus produces more spores, perpetuating the cycle.
Microdochium nivale manifests as white to pinkish fungal growth on infected plant tissues, often accompanied by dark lesions and rotting of roots and stems. These visible signs serve as key diagnostic features for identifying the presence of the pathogen in affected cereal crops.
Damage symptoms
M. nivale is the primary pathogen in the group that causes seedling blight. Seedling blight causes pre- and post-emergence damping off. This can result in seedling death and poor establishment. Surviving seedlings may develop a brown lesion around soil level. This can develop into foot and root rot. Symptomless infections can also occur.
Foot rot becomes obvious from late stem extension onwards. It results in dark-brown staining of the lower nodes. Long dark streaks may also appear at the stem base. On older plants, infection can produce a true foot rot, where the stem base becomes brown and rotten, resulting in lodging and whiteheads. This symptom is less common but can develop very dry seasons.
Bleached ears often show above the point of infection around the milky ripe stage (GS 75). Later infections may result in infection of the grain without obvious bleaching of the ears. The presence of orange/pink spores may also be visible on infected spikelets. As the crop ripens, symptoms become less visible. At harvest, ear blight can result in shrivelled grains with a chalky white or pink appearance, although this is not always the case.
How to prevent foot rot of cereals
- Avoid following maize with wheat in rotations
- Bury soil-surface residue from previous crops, since this is the major inoculum source, especially after (in descending order) grain maize, forage maize, sugar beet or grass.
- Use inversion tillage
- Grow less susceptible varieties
- Treat seeds with Cerall before sowing
- Create good seedbed, direct drilling is preferred
- Control grass weeds
- Judicious use of nitrogen and lime is recommended.
- Harvest high risk crops as soon as possible