sunflower care business

The main care works in sunflower cultivation consist of: weed control, disease control, pest control and irrigation.

weed control
Sunflower is a weed sensitive crop in the stage of emergence of flowering, that is, until the stage when the plant passes the generative stage and records an intense growth rate (5-9 pairs of leaves or 30-40 days from sunrise). From this stage the risk of weeding the crop disappears, since the plants cover the soil well, by shading, which prevents the appearance of weeds. At the same time, due to the growth rate and the surface of the leaf apparatus, the sunflower has a pronounced “suffocating” characteristic of any weed.
Sunflower should be carefully protected from weeding in the first 25-30 days after sunrise, in this case it will form more flowers in the inflorescences.
The use of herbicides is necessary to control weeds.
Depending on the natural conditions and types of weeds affecting the sunflower crop, the following herbicide application options are considered:
1. In areas with frequent rainy springs, in areas endemic to annual monocotyledonous and dicotyledonous weeds, the herbicides recommended by agronomists are administered in the areas simultaneously with sowing, one by one (23 cm wide strip). Herbicides are also taken into account in dry areas, provided that after sowing “stimulate” irrigation is carried out at a low water rate (100-200 m 3 / ha).
2- In areas with often dry springs, in the south and southeast of the country, infested with annual monocotyledonous and dicotyledonous weeds, it is recommended to use herbicides that can be applied to the entire surface 1-5 days before sowing with known measures of volatile herbicides.
3. In areas or areas highly affected by sorghum disease, as well as in irrigated lands, it is recommended to use herbicides recommended by local agronomists. They must fight weeds that reproduce by seeds, as well as crustaceans, and those that run on vegetation, fight crustacean plants that start from the roots. Herbicides can be applied to the entire surface, strictly observing the volatile technology. In dry spring years, if necessary, a watering can sprinkler with 300-400 m 3 of water per hectare, 10-15 days before the application of the herbicide to stimulate the growth of rhizomes from the rhizome.
The control of weeds that can infect the sunflower crop of the previous plant (wheat, barley, corn), should be taken into account, using complex herbicides of wide action. After 20-30 days, during which the herbicide is transferred to the underground perennial organs of weeds, plowing is carried out.

Disease and pest control
Despite the achievements of breeders, sunflower is still a species affected by many diseases. Great damage to this crop is caused by aphids (Plasmopara helianthi), white rot (Sclerotinia sclerotiorum), brown spot and broken stems (Phomopsis helianthi), black spot of stems (Phoma oleracea), gray mold (Botrytis cin r. Sclerotium bataticola) and other sporadic diseases. Which especially paralyze the leaves.
The mentioned disease prevention measures are of a botanical nature and among these measures is of great importance to crop rotation (the plant should return to the same surface after a long period of time (6-7 years, not to plant after common species, soybean, rapeseed, etc.) ).
Currently, the only measure to prevent the attack of aphids is strict compliance with agrotechnical rules regarding the placement of sunflowers in the crop and the wise selection of the previous crop.
Avoiding mono or high nitrogen fertilization, sowing at the optimum time, respecting the optimum density, weed control, and not delaying the harvest contributes to reducing the attack of diseases. Of particular importance is the processing of seeds.
Direct chemical treatments, on vegetation, to combat diseases are expanding more and more. The first treatment is carried out at the beginning of the formation of the “flower bud” (separation), the second a few days before flowering, and the third at 7-8 days after flowering.
Direct treatments against diseases have proven to be effective and economical. Even a single (first) treatment brings significant yield increases. Comparing the various diseases that affect sunflower plants, Romanian breeders have created hybrids of sunflowers that resist the disease well.
Among the most harmful pests for sunflowers to consider: corn duck (Tanymecus dillaticolis) and wireworm (Agriotes spp.) The culture is sometimes endangered. And in the case of these pests, alternation is especially important. Seed treatments are of paramount importance (eliminating any risks of reducing density or damaging the crop).
Wolf (Orobanche cumana), the phanerogam parasite of the Orobanche family, parasitizes on the roots of sunflower plants. Up to 2,000 seeds are formed in a fruit (capsule), and one plant can produce up to 140,000 seeds. From year to year it is transmitted through seeds, which can live in the soil for up to 10-12 years. In Romania, Lupoaia is more common in the southern cultural regions (Dolj, Teleorman, Olt, Ialomița, Constanța, Tulcea, and Brăila) and in Moldova (Iași, Bacău, Suceava).
The main means of control is crop rotation and avoidance as precursors of species attacked by wolves (tobacco, hemp, cucumbers, tomatoes, etc.).

irrigation
The highest water consumption in sunflowers is recorded in the vegetation stages: emergence of flowering – seed formation, when it can rise to 5 mm / day and even more than 5 mm. Calendarually speaking, sunflowers go through a critical phase for getting water throughout July and the first decade of August.
Avoid watering sunflowers before the appearance of the flowering “button” in order to avoid the formation of a fertile representative surface, as well as throughout the flowering period so as not to favor the attack of sclerotinia and not hinder the activity of pollinators.
Depending on the water supply of the sowing soil and precipitation during the vegetation period, 2-4 waterings are given to the sunflower, with the aim of maintaining a minimum ceiling of 50% IUA at a depth of 80 cm. Watering during vegetation is usually concentrated in the interval, 20 days before flowering and 20 days from the beginning of seed formation. Irrigation standards are variable, depending on the growing area (500-700 m3 / ha).

Additional vaccination
Additional pollination of flowers also contributes to increased seed production. For this, it is recommended to install beehives near the sunflower field, at least two hives per hectare. By moving beehives near fields of sunflowers, on the one hand, an increase in production is achieved by reducing the number of dried seeds in the inflorescence, and on the other hand, a higher production of honey, and sunflower is one of the most important honey plants.

Victor Vătămanu

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