Spring care for sunflowers after sowing

The month of April marks the beginning of the sunflower growing season in most regions of the country. At this stage, the majority of producers have already sown the heat-loving crop, while those in the higher mountainous regions are expecting the humidity to increase and will soon sow as well. It is important to note that sunflowers should be sown at 6-7°C average day-night temperature in order to avoid stress from temperature amplitudes, which are often a prerequisite for the development of mildew on sunflowers.

In the initial stages of development, the first problems to watch out for are the appearance of weeds, gray corn borer and wireworms. Part of the fight against them can be carried out easily and preventively with proper soil cultivation and a crop rotation of 5 years.

Weed removal is very important because they take out much more nutrients and moisture from the soil than sunflowers, and in cool years, when crop germination is delayed, weeds appear first and deprive sunflowers of many vital factors. When weeds emerge at the beginning of the growing season, the area can be harrowed with a rotary and tine harrow, and if necessary, the event can be carried out at the 1st and 2nd pairs of leaves. However, heavy rainfall can limit some of the entry into flight, so we must be one step ahead and be prepared for unexpected situations. That is why we advise our clients to apply soil sealing, especially in this unpredictable year, which both keeps us dry until we all stand on our toes and surprisingly gives us heavy rains in early spring.

For this purpose, producers can use Gardoprim Plus Gold, which is suitable for soil application and has a broad spectrum of action against many cereal and broadleaf weeds. It has a high level of selectivity to the crop and ensures an optimal start for sunflowers to achieve high yields. A more affordable option is Summit Agro's herbicide - Pendistar 40SK. This is a soil herbicide used in all types of technologies (conventional, Clearfield, Clearfield Plus, Express) and is widely used in most broadleaf crops, helping in the successful fight against cereal and broadleaf weeds. The active ingredient of the product is pendimethalin, which prevents cell division and stops the development of weeds.
It is still too early to talk about a vegetative herbicide, because even in the warmest regions such as Stara Zagora, sunflowers are just starting to sprout.
While spring crops are starting to develop, the enemies have been preparing all winter and are now eagerly awaiting the spring meal.
Wireworms (Elateridae) are widespread and have a diverse and rich choice of livelihood, because they attack field, vegetable and fruit crops. Damage is mainly caused by adults and larvae, and of important economic importance are mainly the damage caused by larvae, because they destroy the seeds sown in the soil, the sprouts, the young stems and the root system of the plants. When the seeds swell, the larvae first destroy the embryo, and then the endosperm. Only the shell remains from the damaged seeds. When the plants sprout, the larvae gnaw the sprouts even before they appear on the surface of the soil. After germination, they gnaw at the underground part of the plants. The attacks by the larvae are expressed in moves that penetrate the central root of the sunflower plants. In this way, various pathogens enter the plant and as a result, the attacked plants turn yellow, wilt and are very easy to pull out.

The gray corn borer (Tanymecus ditalicollis) is a major pest of corn, but it is now also found in sunflower. The density of the borer is higher in the regions of Dobrich, Pleven and Veliko Tarnovo, which are areas with rich carbonate soils and leached black soil, which is preferred by the enemy. It overwinters as an adult in the soil at a depth of 40-60 cm and when the temperature rises above 4°C it comes to the surface, where it begins to feed on available wild and cultivated plants. The main damage is caused by the larvae, which gnaw at the root collar and interrupt the plant's supply of nutrients.

Wireworm and gray corn borer damage can be easily avoided by pre-treating the seeds with the biological product Naturalis – this is a fungal insecticide for seed disinfection and helps in the fight against 89 types of enemies. The recommended dose of Naturalis is 1-1.2 l per 100 kg of seeds. The product provides a long after-effect, because the fungus falls into its natural habitat, continues to multiply and thus provides long-term protection.

Protecting the crop from stubborn enemies, we also recommend the use of a root biostimulator to ensure uniform and strong germination of the sunflower. Treating the seeds with Radifarm at a dose of 1 l/100 kg of seeds increases seed germination and the supply of microelements necessary for building cold resistance. The product stimulates the elongation of lateral roots and the emergence of secondary roots, as well as combating initial stress during crop development.

In late sowing and warm and dry weather, desert cricket (Gryllus desertus Pall.) and field cricket (Gryllus campestrisL.) can also be found in the field. Like the above-mentioned enemies, they also overwinter in the soil and cause similar damage. The fight against them can be easily controlled with the product Sumi Alpha/Sumicidin 5EK, which is a broad-spectrum pyrethroid with a rapid knockdown effect and long after-effect. The dose is only 4 ml/ha and, in addition to crickets, it also covers many other enemies.

→ In connection with the epidemiological situation, the upcoming Easter holidays and the limited quantities of products in the country, we advise all our customers to plan what products they will need and to contact their regional representatives as early as possible!