Diseases

• Sugar beet seedlings are susceptible to a variety of diseases. Fungal diseases cause seedlings to develop damping-off, seed rot and root rot. Pythium, Rhizoctonia solani and Aphanomyces cochlioides are the most common types of fungi that cause the death of beet seedlings. These fungi live in the soil and infect seedlings during periods of rainy weather. More than one of these fungal pathogens can infect beet seedlings growing in one field.
  
  

Effects

• Pythium, also known as water mold fungus, causes beet seedlings to develop brown, watersoaked lesions on the seedling just after the plant emerges. Pythium can also cause seeds to rot when wet weather conditions are present. Pythium usually occurs when the temperature ranges from 85 to 95 degrees Fahrenheit. Beet seedlings that are stunted or experience damping-off are most often infected with Rhizoctonia solani. This disease is most active when temperatures range from 68 to 86 degrees Fahrenheit. Most Rhizoctonia solani symptoms are below the soil line, but some above ground symptoms include brown sunken lesions on taproots and lateral roots and lesions that completely girdle the root. Warm, wet weather conditions bring the fungi A. cochlioides which is most common in seedlings in late planted fields. Symptoms include brown lesions on the seedlings and black, diseased plant roots.
  
  

Control

• Planting sugar beets early and in well-drained soil is key to growing healthy plants. Avoid planting seeds deep in the soil and select seed treated with fungicides. Rotating crops may also help avoid fungal diseases in beet seedlings. Keep weeds under control near your beet seedlings, as some species of weeds such as pigweed and kochia become infected with fungi, which can spread to your sugar beets.
  
  

Considerations

• According to Iowa State University, home gardeners can begin planting sugar beets in April and early August is the latest planting date. Proper planting depth is important when growing sugar beets. Plant your beets at a depth of 1/2 inches and space rows 1 1/2 feet apart. Dry soils often cause poor germination in beets. Water your plants periodically when the weather is dry to promote germination. Thin beet seedlings to 3 to 4 inches apart for best results, as overcrowding is a common problem in beets. Remove small, weak seedlings and leave the larger seedlings for best results.