How to Protect Sunflower Seeds from Pests and Fungal Disease

The international organization FAO annually records outbreaks of fungal epiphytoties on sunflower crops around the world. The reason for this is the saturation of crop rotation with pathogens of harmful fungal diseases, which can only be controlled with an integrated approach in the crop protection system. Yield losses due to the harmful effects of fungi on cultivated plants sometimes reach more than 50%.

Sunflower Advices to the agronomist
Published by: 18.03.2019

Protecting sunflower from diseases

Sunflower is one of the most important oilseeds in the world. In Ukraine, it is one of the most profitable crops, despite its rather low average yields. Climatic and economic factors contribute to a significant increase in sunflower acreage, especially in the steppe zone, and sometimes even to its cultivation as a monoculture for several years. The use of low doses of mineral fertilizers, limited by moisture deficit in the central and southeastern regions, non-compliance with the technology of basic and pre-sowing tillage and sowing, the use of mainly cheap generic products in minimal quantities in the plant protection system and neglect of technological aspects of chemical and biological protection products - all this has led to catastrophic contamination of fields with aggressive fungal pathogens and, as a result, high losses of sunflower grain yield per hectare.

Below are the most common sunflower diseases in Ukraine. The harmfulness of various diseases in epiphytoties can cause up to 100% crop loss, so comprehensive genetic, chemical and biological protection of seed and crops is extremely important in the technology of growing this crop.

  • Rust - Puccinia helianthi Schw
  • Peronosporosis - Plasmopara helianthi Novot. f. helianthi
  • Gray rot - Botrytis cinerea Pers.
  • White rot or sclerotinia - Sclerotinia sclerotiorum (Lib.) de Bary
  • Dry rot of the basket - Rhizopus stolonifer var. stolonifer (Ehrenb.) Vuill.)
  • Downy mildew - Plasmopara halstedii (Farl.) Berl. et de Toni.)
  • Powdery mildew - Erysiphe cichoracearum f. helianthi Jacz. and Leveillula compositarum f. helianthi Golovin.
  • Root rot - Fusarium spp, Rhizoctonia spp.
  • Ash rot of the stem (charcoal rot) - Sclerotium bataticola Taub.
  • Verticillium wilt - Verticillium dahliae Kleb.)
  • Septoria (brown spot) - Septoria helianthi Ellis et Kellerm
  • Alternaria alternata (Fr.) Keissl.
  • Phomosis (black spot) - Phoma oleracea var. helianthi Sacc.
  • Phomopsis (brown spotting of stems) - Phomopsis helianthi Munt

The main causative agents of sunflower diseases are fungi of different classes, and in the field, a complex of mixed infection is more common. We should not forget about the significant impact on plants of bacterial infections, which are mainly the result of fungal infection.

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Most fungal pathogens of sunflower are characterized by high temperature conditions for their development and peculiarities of the way the infection is transmitted between plants. Most pathogens are transmitted to a new plant through plant residues, soil and seeds. Therefore, it is extremely important to ensure reliable protection of young sunflower seedlings from the harmful effects of pathogens in the early stages of plant development and during the growing season. This is only possible by creating a reliable fungicidal barrier on the seed.

Effective inhibitors of Fusarium development are such active ingredients as fludioxonil and metalaxyl-M. Downy mildew (peronospora) - metalaxyl-M (due to the systemic qualities of this substance, it also protects young plants from aerogenous spread of infection).

Against pathogens of Alternaria, Rhizoctonia, Bacteriosis, downy mildew, coal rot - the active ingredient thiram is effective (it acts in contact, which provides protection against seed and soil infection). Against white and gray rot, phomosis, phomopsis, fusarium, verticillium, seed mold, thiabendazole is effective (systemic action substance, stops the development of diseases on the surface of seeds and inside them, protects against infection from the soil). Fludioxonil is a broad-spectrum contact fungicide with extended activity. It is limitedly absorbed by seeds and moves little in the seedlings, but reduces the growth of pathogen mycelium.

Given that a single-component product is not enough to fully protect sunflower seeds and seedlings, complex fungicides should be used.

We recommend paying attention to the treatment of purchased seeds with the above-mentioned active ingredients, as treatment with these products can protect sunflower seeds and seedlings at the initial stages of crop development.

Given that the crop rotation is saturated with such crops as sunflower, rapeseed, soybeans, and cereals, the population of soil pests is extremely high. Wireworms, copperheads, weevils, May beetles, scoop larvae and meadow butterflies cause great damage to young sunflower seedlings and even lead to a significant reduction in density.

That is why we emphasize the expediency of insecticide protection of seed. The following active ingredients are effective and efficient:

  • Imidacloprid
  • Thiamethoxam
  • Bifenthrin
  • Fipronil
  • Diazinon (soil insecticide against the bear).
  • Microbiological preparations based on Bacillus thuringiensis, the so-called Bt preparations (analogues: bitoxibacillin and lepidocide), are used against caterpillars of scale-winged pests.

Only an integrated approach to plant protection from seed treatment to the end of the sunflower growing season will ensure the realization of the maximum genetic potential of any hybrid in your field.