Issue link: https://www.e-digitaleditions.com/i/1233627
Establishing a good stand is important to reduce competition from weeds and protect plant health throughout the growing season. Best management practices including pathogen-free and high- germination seed, variety selection, crop rotation and using a seed treatment can go a long way toward protecting your crop. Poor emergence is oen the first sign of damping off. Damping off can occur before plant emergence or in the young seedling (post-emergence damping off ). Symptoms include poor stand, yellow seedlings with no secondary roots or a brown/black tap root, and plant death (Figure 1). Damping off is caused by a number of pathogens including Pythium spp., Fusarium spp., and Rhizoctonia spp., among others. It is soil borne and is favored by no-till management due to cooler, weer soils at spring planting. Plant high quality seed and always use a fungicide seed treatment to manage damping off. e seed treatment should contain metalaxyl or mefanoxam for control of Pythium in addition to another fungicide for control of Fusarium, Rhizoctonia, etc. e selection of seed treatment will depend on what is available at your retailer. Decisions can be aided by the North Dakota State University Fungicide Guide, which is updated yearly, and the High Plains Integrated Pest Management (IPM) Guide (wiki.bugwood.org/HPIPM). Aer the seedling has emerged, continued cool wet weather oen results in root rot. Symptoms will include stunted, yellow plants and may be mistaken for nitrogen deficiency (Figure 2). When the plant is dug up, the roots will be much thinner than a healthy plant or there may be no secondary roots at all. Roots will be discolored, and the color and paern of discoloration depends on the pathogen infecting the roots. ere are four main types: Pythium root rot, Rhizoctonia root rot (bare patch), Fusarium root rot, and Aphanomyces root rot. ese fungal diseases affect a very broad host range, so crop rotation is of limited efficacy. FIGURE 1. Damping off is caused by many different fungi. Above, Kabuli chickpeas to the left are more susceptible than desi chickpeas, right. Note the significant loss of stand due to damping off. FIGURE 2. Lentil plants yellowed due to root rot, below. DISEASE PROBLEMS AT ESTABLISHMENT DAMPING OFF ROOT AND CROWN ROTS Photo: Mary Burrows, Montana State University Photo: Mary Burrows, Montana State University farm406 50