Expert advice

Spraying to control weed in winter rape

The extended rape harvest, due to the unstable and particularly unfavourable weather conditions, is slowly coming to a close in Poland. Estimating the crop is just one of the few tasks currently waiting for the farmers. 

Due to the very long growing season of rape, lasting approx. 11 months, this plant requires a professional approach in terms of agricultural technology, from sowing until the harvest. Treatments of the crop, the selection of a suitable type, fertilisation and sowing at the appropriate time are just some of the key tasks in the next period. Proper management of a rape plantation is related to effective control of weed, including self-seeders of crops, which in the initial period of development of plants are great competitors for water, light and nutrients. Weed that will remain will contribute to extension of the buds and elongation of the root neck above the soil level, leading to greater susceptibility to freezing and failure of rape in the winter. For this reason, autumn treatment of rape can be assumed to be a basic task, dependent on the expected or current weed levels, weather conditions, costs of treatment and individual decisions of the farmer.

In case of herbicidal protection of rape, in practice one uses soil treatments before the crop emerges, or leaf treatments when the weed and rape emerge. The most popular active ingredient used for the protection of rape before emergence is clomazone, forming a part of the product Szabla 480 EC. Used within three days after sowing, at 0.25 l/ha, it effectively controls cleavers, which are tough competition for budding rape, and additionally such types of weed as: the common chickweed, the purple dead-nettle, the common henbit, the birdeye speedwell or the shepherd's purse.

In order to expand the range of the controlled weed, e. g. to include particularly dangerous species from the Asteraceae family, clomazone may be used together with metazachlor 500 SC.