CLS – Cercospora Leaf Spot
Scientific Name: Cercospora asparagi, Cercospora beticola
Type: Fungus
Cercospora Leaf Spot is a world-wide fungal disease that affects the growth of asparagus, beets, carrots, corn, eggplants, peppers, soybeans, and tomatoes. It is the most destructive foliage disease of beets in Colorado, Nebraska, and Wyoming. Leaf spots occur on leaves. Symptoms include lesions of round or angular brown spots with green, brown, gray, or white centers. The leaves turn yellow, wither, and eventually die off and the whole plant becomes defoliated. The infected plants should be removed to avoid further infestation. The disease is favorable when temperatures are 55-65 F and usually occur between June and August when moisture and humidity are very high. Fungicides can help manage the disease. The best option is to use disease resistant varieties.
FCRR– Fusarium Crown & Root Rot
Scientific Name: Fusarium oxysporum f. sp. asparagi, Fusarium proliferatum, and Fusarium moniliforme
Type: Fungus
Fusarium Crown & Root Rot is a devastating world-wide soil borne disease that affects the growth of asparagus and tomatoes. The disease affects the roots. Symptoms include wilting, stunting, yellowing, and dry rot of the crowns. Often the crown turns a brown color when it is infected with the disease and then rapidly dies off. Once the plant is infected, it is extremely difficult to manage the disease once the fungus is established in the field. Plan on using a 5 year crop rotation and avoid planting asparagus in the same location, year after year as the disease can survive in the soil for a long time. The best option is to use disease resistant varieties.
R - Rust
Scientific Name: Puccinia asparagi, Puccinia sorghi
Type: Fungus
Rust, also known as Common Rust, is a world-wide soil borne disease that affects the growth of asparagus, cantaloupes & melons, corn, and lettuce. It is one of the most destructive disease in growing asparagus in the United States. The disease affects the ferns on asparagus. Lesions develop and turn cream-orange color, then turn a reddish-brown color, then eventually turn a brick red or rust color. During the winter the lesions will turn a black color. Severe infestation stunts or kills young asparagus shoots. The infected plants should be removed to avoid further infestation. When corn is infected the disease affects the upper and lower leaf surfaces, where small specks appear on the leaves, then develops into small tan spots, and distinguished by cinnamon-brown pustules. These pustules blister and turn dark brown to black late in the season. Corn stalks are weakened and stalk rot potential increases. Significant damage to upper leaves results in significant yield losses. Common rust spreads by windblown spores. The disease is also favorable cool and moist conditions when temperatures are 68-72 F, and usually occurs when there is nine hours of wet weather. The best option is to maximize air movement between the plants and to use disease resistant varieties.