Rust in sunflowers

A picture of sunflower leaves suffering from rust

Rust in sunflowers.

Causative factor : Puccinia helianthi

Symptoms and damages

Sunflower rust is considered the most important disease that affects sunflowers and causes great losses. The disease appears in all areas of its cultivation, especially on susceptible varieties, which leads to a decrease in seed yield and a decrease in the oil content of the seeds. The infection appears in the form of pustules characteristic of the fungus, with a reddish-brown color on the upper surface of the leaves. They may join together to form large pustules that turn black, and then the leaves fall when the infection becomes severe.

A temperature of 25-30 degrees and a humidity of 85-90 °C are factors that help the spread of the disease.

Prevention and treatment

  • Collecting plant waste and burning it.
  • Reducing air and ground humidity by regulating irrigation and reducing agricultural density.
  • Do not over-fertilize with nitrogen.
  • Follow an appropriate agricultural cycle.
  • Cultivation of resistant varieties.
  • Spraying with fungicides (di-tiocarbamate) or copper compounds before the infection appears.
  • When the infestation begins to appear, spraying with pesticide (Planta Fax EC20% at a rate of 350 cm3/100 liters of water). Or Baycor EC300 at a rate of 75 cm3/100 liters of water

Rust in sunflowers - Plant World

Sunflower rust is considered one of the most important diseases that afflict sunflowers and causes them great losses. The disease appears in all areas of its cultivation, especially on susceptible varieties. The presence of the disease has been proven in all governorates of Lower Egypt, especially in humid areas, with the infection intensifying the closer we get to the coastal areas due to suitable conditions. The weather causes significant losses in the crop, as the severity of infection in some areas ranges from 61-86%, which leads to a decrease in seed yield from 8-16% and a decrease in the oil content of seeds from 8-11%.

Pathogen Casual pathogen

The disease is caused by a fungus Puccinia helianthi

Symptoms

The infection appears in the form of pustules characteristic of the fungus, with a reddish-brown color on the upper surface of the leaves. They may join together to form large pustules. The infection appears first on the large lower leaves close to the surface of the soil and then moves upward.

The disease begins to appear during the flowering stage, and when the infection becomes severe, the leaves dry out and turn black, and pustules also appear on the stems, leaf petioles, and flower stems.

Conditions suitable for the emergence and spread of the disease

The disease spreads strongly in wet seasons, and heavy, wet soil helps increase the disease, in addition to the presence of infected plant debris, which contains T. spores, as a source of infection in the following season.

Rust in sunflowers - Plant World

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