Expert advice

Controlling weed in sugarbeet

The technology of point sowing of the sugar beet assumes a low density of the plants per square metre, spacing rows every 45 cm and a separation between plants in a row of up to 18 cm – these are ideal conditions for weed sprouting and growth.

Preventive measures

Sugar beet, in the initial stage of growth, is slow to cover areas between the rows, which also facilitates intense weed growth. As a result of this, competition for water, nutrients and space in the initial phase of the plantation, between the sugar beet plant and the weed seedlings, is very tough.

Weed control at the plantation should primarily include preventive measures such as a position in crop rotation, farming, timely sowing and mineral fertilisation. The use of non-chemical methods in weed control is insufficient, hence one should assume a suitable strategy in controlling them. Wrongly executed treatments and procedures against weeds may limit the crop of sugar beet roots, the sugar content, and additionally hinder the harvest itself. Hence, it is important to pick the appropriate defence measures for plants to control the weeds from the time of emergence until the coverage of space between the rows. Appropriately selected products should be characterised by a broad spectrum of controlled weeds, various mechanisms of action and routes to reach the plant. It is recommended to pick formula mixes conforming to these criteria, or to create spray mixes.

Herbicidal treatment

Weed of beets are controlled with the use of two-three herbicidal treatments that permit one to achieve a field free of monocots and dicots. The adherence to a system of several treatments using the right products permit one to effectively control weeds during their initial growth stages, and hence – their systematic elimination. The treatment should be repeated when the weeds show up again. Warm and humid weather reduces the period between treatments, and a drought increases this period. Weeds should be controlled if they have up to four leaves, hence, it is important to frequently control the sugar beet plantations visually. the choice of the first treatment date is very important, because, if conducted at the right moment, it will clear away all burdensome weeds and none will 'escape'.

Thorough weed removal

On plantations, where the field management undergoes simplifications, the field surface usually has remains of plants from before sowing, and weed may emerge. We recommend in such a case, before sowing or right after sowing, that the product Agrosar 360 SL be used. It will clear away all weeds irrespective of their growth phase, and is completely safe for the sown sugar beet. In agricultural practice, Agrosar 360 SL may be added to the first herbicidal treatment if it is performed up to a few days after sowing (must be done before the beet emerges).

Soil and leaf treatments

To achieve herbicidal protection of a sugar beet plantation, one should pick a product based on active agents that act both on the soil as well as on the leaves. In that case, one may control weeds that have started sprouting within the soil, as well as those in the leaf phase. Products conforming to these criteria are Agent 180 EC and Akord 180 OF. They control most of the burdensome weeds in the farming of sugar beets: the field pansy, the field mustard, the common chickweed, the goosefoot, cleavers, the red-root amaranth, the shepherd's purse and the field pennycress. In order to broaden the spectrum of the controlled weeds, we recommend a tank mix of the following products: Faworyt 300 SL (0.15-0.2 l) + Akord 180 OF (1.5 l/ha). Faworyt 300 SL is a good component of spray mixes, and if given in the full dose of 0.3 l/ha, it effectively controls, among others, the creeping thistle, the field chamomile, the false mayweed and the black nightshade. A somewhat different solution permitting only the control of weeds in the leaf phase is the use of Sarbeet Duo 160 EC (1.5-2.0 l/ha). This product will eliminate thee goosefoot, the red-root amaranth, the field mustard, the common shickweed, the shepherd's purse and the field pennycress. Depending on the volume of weed, the treatment may be repeated even up to three times per season.

The first herbicidal treatment may be executed by a product that only works in the soil, based on i. e. the active agent lenacil, which controls weeds in low growth phases (cotyledon phase). For subsequent treatments, one should consider adding to this the active agent Sarbeet Duo 160 EC – it will control weeds in upper growth stages (up to the fourth leaf), which were not eliminated by the first treatment.

In sugar beet plantations, one frequently meets the problem of self-seeders of cereals and infestation by other monocots. They may also limit the harvest of beet roots and may be the source of cereal diseases in the subsequent growing season. A herbicidal treatment against monocots is performed when the sugar beets have between the first and the third pair of leaves (phase BBCH 11-13) using Labrador 05 EC. The dose should be adapted to the weed species to be controlled, such as: the common couch (3.0 l/ha), the common windgrass (1.2 l/ha), the black twitch (1.0 l/ha).