Recommendations for the Application of Herbicides Containing Tribenuron-Methyl

Tribenuron-methyl

Herbicide containing tribenuron-methyl (Express, Alfa-Star, Granstar Pro) is a postemergence systemic herbicide for controlling dicotyledonous weeds in sunflower crops. The product quickly (within a few hours) penetrates weed plants and stops their growth and development. The first signs of herbicidal action appear 5-8 days after application, and the final death of weeds occurs within 2-3 weeks. The herbicide acts only on those weeds that are germinating at the time of application.

Benefits of using the herbicide:

• a wide range of annual dicotyledonous weeds to be destroyed compared to traditional soil-applied herbicides;
• the only way to control thistle in the period after sunflower emergence;
• flexibility in the time of application of the herbicide - in the period from 1 to 4 pairs of true leaves in sunflower;
• the possibility of applying the herbicide with different consumption rates or in two stages, depending on the weediness of the field and the specific field situation;
• no restrictions on sowing the next crop in the crop rotation.

Important elements of herbicide application technology:

The technology involves sowing a specialized sunflower hybrid and applying herbicide after the emergence of cultivated plants.

Recommendations for use for sunflower hybrids Sunny mood, Matador, Dragon (25 g of herbicide per 1 ha):

Recommendations for use for sunflower hybrids Amato, Folk, Shannon, Auris (50 g of herbicide per 1 ha):

Discoloration (partial yellowing) of sunflower plants and/or temporary growth retardation (up to 5 days) after application is a physiological reaction of hybrids to the product. As a rule, normal growth and appearance of plants is restored within 1-2 weeks.

However, an increase in the single rate (higher than recommended) of the drug consumption can lead to deformation or absence of the main basket and the formation of unproductive additional baskets in the leaf axils instead.

The developmental stage of cultivated plants:

The product is applied in the period from 1 to 4 pairs of true leaves in sunflower plants once or in two stages of half the dose during the specified period.

Weed growth stage:

The effectiveness of the herbicide application depends on the stage of weed development at the time of application. Maximum effectiveness will be observed when weed plants are at the following stages of development:

• ragweed - up to 2 true leaves each;
• white quinoa - up to 4 true leaves at most;
• tenacious marigold - up to the phase of 3-4 rings;
• other annual dicots - up to 4-6 true leaves;
• perennial dicotyledons (thistles) - rosette stage - beginning of stem growth.

Factors influencing the level of resistance of sunflower hybrids to tribenuron-methyl-based herbicides:

The resistance of sunflower hybrids to herbicide is due to their specific genetics. However, there are a number of factors that can significantly affect the level of resistance of a hybrid during the period of herbicide application. These are factors of natural origin and factors of chemical nature.

Natural factors:

• dry weather conditions;
• conditions of excessive moisture;
• low (less than +12◦С) or high (more than +25◦С) air temperatures during the application period;
• sharp fluctuations in night and day temperatures during the period of herbicide application.

Chemical factors:

• negative effect of other herbicides, if their application is close in time to the application of a preparation containing tribenuron-methyl;
• insecticides from the group of organophosphorus compounds;
• fertilizers applied by spraying during the period of application.

The warnings in the technology of applying the herbicide Granstar are aimed at preventing toxicity of sunflower plants:

• it is not recommended to grow sunflower on fields where herbicide inhibitors (sulfonylurea derivatives, imidazolinones, triazole pyrimidines) were used on the predecessors;
• sowing of sunflower is optimally carried out 2 weeks after the application of continuous action preparations (glyphosates), as their decomposition in the soil depends on the activity of soil microflora;
• do not apply the product within three days after heavy rains or after artificial irrigation;
• if it is necessary to apply anti-cereal herbicides, the interval between the application of such preparations and Granstar herbicide should be at least 7 days;
• it is not recommended to use insecticides from the group of organophosphorus compounds;
• it is forbidden to fertilize vegetative sunflower plants by spraying simultaneously (in tank mixtures) with the application of Granstar herbicide, as the herbicide's entry into cultivated plants is accelerated, which may cause their toxicity.

Control of sunflower borer resistant to tribenuron-methyl herbicide:

Sunflower broomrape is resistant to herbicide-inhibitors (sulfonylurea derivatives, imidazolinones, triazole pyrimidines).

To destroy the carrion of such sunflower when growing the next crop of the crop rotation, it is mandatory to use drugs with a different mechanism of action, for example, growth and development regulators (products containing 2,4-D, dicamba, fluroxypyr, clopiramide, MCPA).