Leaf and Stem Rust

Leaf and stem rust diseases

Wheat is affected by three rust diseases: leaf, stem, and stripe rust. Leaf rust is the most frequent of the three diseases in the Central Great Plains and other wheat-growing regions of the United States. Leaf rust disease is a yearly occurrence in some states. Stem rust is not as common as other rusts because many varieties are now resistant to the disease. Stripe rust is becoming an increasingly serious disease, with recent outbreaks in the Great Plains states.

Identification and lifecycle of leaf rust: 

The fungus Puccinia triticina causes leaf rust, also known as brown rust. This rust disease can be found in areas where wheat, barley, and other cereal crops are grown. Only the foliage is affected by leaf rust. Dusty, reddish-orange to reddish-brown fruiting bodies appear on the leaf surface as recognizing symptoms. These lesions produce a large number of spores that can cover almost the entire upper leaf surface. Wind and splashing water spread leaf rust spores. Temperatures ranging from 59 to 68 F and at least six hours of wetness on the surface of the leaves are optimal environmental issues for disease development. Lesions form within seven to ten days of infection in wet weather and ideal temperatures, and spore production restarts the disease cycle. Leaf rust fungi overwinter in wheat crops in the southern states. These overwintering fungi produce spores in the spring, blown north to cause illness wheat in the Great Plains and Midwest states.

Disease Symptoms:

Leaf rust is most commonly found on leaves, but it can also be found on glumes and awns. On the upper surface of infected leaves, symptoms include circular or oval orange pustules. The spores within these pustules are quickly dislodged and leave orange dust on hands and clothing. As the wheat ripens, this orange stage of the fungus transforms into a new stage of the fungus, which is black, and a mixture of orange and black stages is often found on a leaf.

Crop Damage by leaf rust:

Leaf rust causes the most damage when serious rusting covers the upper leaves before flowering. Early infection can cause weak plants with poor root and tiller growth. In some areas, they have exceeded 50%, depending on weather conditions, early disease in the growing season, and a highly susceptible variety. A study found that yield losses range from 30 to 40% when the infection becomes severe before flowering, with flag leaf damage exceeding 60% and, in some cases, reaching 100%.

Identification and life cycle of stem rust:

Leaf rust, commonly known as brown rust, is caused by the fungus Puccinia triticina. This rust disease is widespread in places that cultivate wheat, barley, and other cereal crops. Leaf rust only affects the foliage. As distinguishing signs, dusty, reddish-orange to reddish-brown fruiting bodies develop on the leaf surface. These lesions produce an abundance of spores, which can cover nearly the whole top leaf surface. The wind and splashing water dispersed leaf rust spores. Temperatures ranging from 59 to 68 ° F, as well as at least six hours of wetness on the surface of the leaves, are optimal environmental conditions for disease development. . In rainy conditions and optimum temperatures, lesions develop within seven to ten days of infection, and spore production begins the disease cycle. Fungi that cause leaf rot to overwinter in wheat fields in the southern states. These overwintering fungi release spores in the spring, which are blown north and cause wheat disease in the Great Plains and Midwest regions.

Crop Damage by stem rust:

The illness spreads quickly and can move vast distances using the wind or other modes of transportation such as farm equipment or plant debris. In severe cases, the disease can transform a healthy crop into a tangle of black stems just weeks before harvest, resulting in shriveled grain. According to the United Nations (FAO), stem rust can reduce wheat production by 70% or more. Pustules turn black as plants develop. A variety of diseases can weaken stems and cause lodging. North and west of Manitoba and southeast Saskatchewan, rust is typically not a concern. The losses are the result of shriveled seed and a lower seed yield.

Symptoms of stem rust:

The reddish-colored urediniospores that develop on wheat leaves, stems, and heads are the most visible. Wind spreads these spores, which infect wheat or barley plants. Different spores are generated on wheat and barley, allowing the fungus to live on straw during winter and spread solely with the straw. Early in the spring, orange- to salmon-colored aecia appear on the lower leaf surfaces of barberry and are transferred to wheat by the wind. When stem rust is severe, diseased plants may get lodged, although the illness is seldom that bad in the Pacific Northwest.

Treatment of Stem rust:

Early infectivities are most damaging so that early planting may reduce losses. Here is some treatment rust of diseases:

  • Plant rust-resistant cultivars that have been suited to the circumstances. When rust outbreaks develop, be ready to switch cultivars.
  • Plant after the suggested Hessian fly-safe date for your location. Early planting raises the likelihood of fall illnesses. Severely diseased seedlings are stressed and more vulnerable to cold damage.
  • Appropriate, balanced fertilizing based on a soil test should decrease the likelihood of severe yield loss due to rust. High N rates in the absence of enough P and K may exacerbate rust severity, decreasing grain yields.
  • Fungicides are offered to combat wheat leaf rust. Some chemicals, such as Trivapro® and Tilt fungicide, can protect your crops from leaf disease without inflicting any harm. When the variety is susceptible, the disease has begun early, and the flag leaf is in danger of getting infected, fungicide application is typically advised.