Forest Rebuilding

Production losses caused by certain pathogens of sunflower can reach up to 30-50% and in some cases may even lead to compromised culture. The level of damage depends on factors such as infection occurs when the intensity of the attack, tolerance hybrids grown or culture technology applied

Throughout the growing season, sunflowers can be attacked by various diseases, especially fungal infections leading to staining and necrosis of leaves (Alternaria spp, Septoria helianthi) or stem rot (Phomopsis helianthi, Phoma maccdonaldii, Sclerotium bataticola) and calatidiilor (Sclerotinia sclerotiorum, Botrytis cinerea). It is necessary to combat these pathogens of sunflower vegetation by chemical treatments.

The main diseases of sunflower

In the following we describe the main diseases affecting sunflower culture and factors contributing to the initiation and evolution of attack.

• brown staining is caused by strains of the pathogen Phomopsis helianthi and can cause significant damage (10-50%), depending on when infection occurs. After drying premature leaf / plant and breaking their negative influence pathogen manifests itself on the MMB and oil content in seeds.

• Septoria spp Alternaria are pathogenic helianthi with great destructive potential in terms of years of heavy rainfall, high humidity air and moderate temperatures average. The attack is manifested by staining and foliar necrosis, basal leaves from floors and sometimes progressing to complete defoliation, premature plant. This negatively influences the formation and filling achenes.

• Sclerotinia sclerotiorum is a pathogen known by his polyphagia particularly large, but also many forms of attack on sunflower plants. You can install early stage floral button until the maturity stage of calatidiilor. Infections is marked by the presence of soft-colored spots, usually on the surface calatidiului, but sometimes on the stem or floral button.

If the weather is wet, the surface patch can see the mushroom mycelium white felt. Evolving, infection may include all or a portion of it calatidiul. The fungus produces sclerotia (of different shapes and sizes) calatidiului inside and on its surface as a network around the seed.

Calatidiilor infection with this fungus is caused by spores (ascospori) formed after germination of sclerotia are carpogenic type soil. This type of germination of sclerotia is induced under certain conditions of temperature and humidity. Thus, air temperatures of 20-25 ° C, 15-18 ° C soil and high humidity at ground level are optimal for sexual germination of the fungus.

Subsequently, the development of new infections is subject to temperature and humidity, so that above 25 ° C and the presence of water on calatidii provide optimal conditions for spore germination.



Rainy summers disease

• gray mold Botrytis cinerea produces the calatidiilor and attacks from the late phase of flowering to physiological maturity stage. Symptoms consist of mold stains on calatidiu, this consistency getting soft tissues. Stains will be covered with gray spray (fungus spores), which will ensure the spread of infection to healthy plants.

First of pathogen contamination occurring in the flower tube, spore germination is favored by the presence of pollen. Subsequent infection of other tissues include calatidiului, infecting including seed.

Rainy summers is gray mold disease, infection periods by setting up high humidity and low temperatures moderate. Transmission of disease from one year to another is through infected plant debris and seed.



Phenological stage optimal treatment

For high efficiency is important in preventing the attack phase where chemical interferes with treatment.

To limit helianthi Phomopsis attack, research has shown that very important is the application of preventive chemical treatments before symptoms appear on the leaves. Phenological stage of the plant is the first treatment for 6-8 pairs of leaves at this stage it is possible to apply terrestrial worn tractor spraying machines.

In light of changing environmental conditions and processes of infection of the crop, a second treatment is recommended in the early stage of flowering, at the first ligulate flowers. At this stage, treatment is applied with air assets.

Plant protection products approved for use in our country include a number of fungicides with activity against pathogens Phomopsis helianthi and Alternaria spp namely: Acanto Plus (0.6 L / ha), Amistar Extra 280 SC (0.75 l / ha), Impact 125 SC (1.5 l / ha), Impact 25 SC (0.75 l / ha), Mirage 45 EC (1.0 l / ha), Painter (0.5 l / ha), Rovral 500 SC ( 1.0 l / ha), Sphere 535 SC (0.4 l / ha) Tanos 50 WG (0.4 kg / ha), Topsin 70 PU (1.0 kg / ha), Topsin 70 WG (1.0 kg / ha), Topsin 500 SC (1.4 kg / ha).

Chemical control of white mold and gray through vegetation treatments have been studied by many researchers and it was found that optimal phenological phases of their application to reduce the impact on production rots in calatidiu are: first treatment at the beginning of flowering and the second at 10-15 days after the end of flowering. When applying only a single treatment, the warning is the capital attack frequency is above 3%.

To combat using one of the following fungicides: Acanto Plus (0.6 L / ha), Amistar Extra 280 SC (0.75 l / ha), Eyetak 450 (1.0 l / ha), Impact 125 SC (1, 5 l / ha), Impact 25 SC (0.75 l / ha), Mirage 45 EC (1.0 l / ha), Painter (0.5 l / ha), Prosaro 250EC (0.75 l / ha) , Rovral 500 SC (1.0 l / ha), Sphere 535 SC (0.4 l / ha), Tanos 50WG (0.4 kg / ha), Topsin 70 PU (1.0 kg / ha), Topsin 70 WG (1.0 kg / ha), Topsin 500 SC (1.4 kg / ha).

Option to apply 1, 2 or 3 treatments must take into account vegetation suitability or expected climatic conditions for pathogen development, the stage of infection in each culture, and the degree of resistance to these pathogens of cultivated hybrid.