Beet rust

Summary

Beet rust (BR) is a foliar disease that is caused by the fungus Uromyces betae. Heavy infection cuts bulb yield.

 

Identification

BR produces orange-brown pustules on both surfaces of beet leaves, sometimes in a circular pattern. In some cultivars, lesions surround the pustule.

 

Importance

Typically not a major problem in feed crops. Infection is restricted to older leaves. However, under prolonged moist, mild weather, BR can cause substantial leaf damage and DM yield loss.

 

Spread

U. betae survives between crop cycles on infected plants (mostly volunteers) and in crop debris. Spores are produced in spring and transported by wind.\

 

Management

Control volunteers. Fungicides are available.

 

 

 

Cercospora leaf spot

Summary

The fungus Cercospora beticola affects both leaves and bulbs, with potentially serious yield losses. High temperatures and humidity, typically in late summer, increase damage.

 

Identification

Small round leaf spots (3-5 mm diameter) are first found on older leaves then transfer to younger leaves. Tan to light brown centres have reddish-brown borders. In heavy infections, spots coalesce and leaves turn brown but stay attached to the plant.

 

Importance

CLS occurs sporadically but can result in significant DM loss.

 

Spread

CLS survives between crops via residues, soil, seed and infected plants. Spores are produced in spring and transferred by wind, water splash, insects and equipment. Spread is greatest when leaves are wet at night and days are warm and humid.

 

Management

Rotate crops every year. Sow seed only from reputable sources. Use treated seed. Keep infected residues 100 m away from other susceptible crops. If irrigating, avoid prolonged leaf wetness; water from mid-day when leaves are dry. Fungicides are available.