Magnum — selective herbicide for combating annual and some perennial broadleaf weeds in cereal grain and flax crops. It contains 600 g/kg of mesosulfuron-methyl and belongs to the chemical class of sulfonylureas.
This herbicide suppresses many species of annual and perennial broadleaf weeds, including difficult-to-control ones such as common burdock and yellow ragwort. The application rate is low (8–10 g/ha), making the treatment very economical — the cost of treating 1 ha of crops is lower than that of 2,4-D. Magnum has a sufficiently long application window on cereals — from the 2–3 leaf stage of the crop to the end of tillering. Thanks to its modern formulation (water-dispersible granules), the product dissolves well in water and is easy to apply. Both ground and aerial spraying are permitted.
The following weed species are sensitive to Magnum: Ambrosia psilostachya, common burdock, common burdock, Veronica persica, common vetch, delicate geranium, docks (various species), field mustard, Lesch's fennel, medicinal fennel, annual daisy, Scoparia sophia, Lactuca lacophylla, medium starwort, field cabbage, stinging nettle, common sowthistle, common sunflower, field radish, odorless chamomile, roof thistle, common smolivka, curly dock, inverted shield fern, delicate horsetail, field violet, purple nettle, field chickweed.
Moderately sensitive species include: blue chicory, field bindweed, Tatarian buckwheat, Tatarian lettuce, field ragwort, large plantain, medicinal dandelion, water-lily (various species), marigold (various species), common lady’s mantle, black nightshade, prickly purslane, wormwood (various species), clover (various species). The use of Magnum in tank mixtures with other herbicides can significantly enhance the suppression of these weed species.
Since 2003, the company "August" has annually conducted demonstration trials of Magnum in many regions of Russia and some CIS countries, both as a standalone product and in tank mixtures with various herbicides. Institutions, agricultural experimental stations, regional plant protection stations, large farms, and farmers participate in organizing and conducting these trials. Over this time, the use of tank mixtures has increased more than threefold. Herbicide combinations are gaining increasing demand among producers. This is clearly demonstrated by the results of using tank mixtures in crop cultivation. Generalized data (see chart) show that in all regions, experimental plots have yielded significant grain yield increases with an average profitability of up to 375% compared to control plots without herbicides. In these cases, weed mortality in cereal crops ranged from 87–95%.
Research has shown that the maximum results from using tank mixtures are achieved when applying them during the early growth stages of annual (2–4 leaves) and perennial (rosette stage) weeds, at the following application rates:
on cereal crops — Magnum (7 g/ha) + Dialen-Super (0.2 L/ha); Magnum (5 g/ha) + Herbitoks (0.8 L/ha);
on flax — Magnum (7 g/ha) + Herbitoks-L (0.6 L/ha); Magnum (5 g/ha) + Herbitoks-L (1.0 L/ha);
on fallow land for cereal crops — Magnum (10 g/ha) + Tornado (2.5 L/ha).
The following advantages of Magnum tank mixtures with other herbicides were noted.
Broadened herbicide spectrum
Compared to the use of Magnum alone, its combinations with herbicides from other chemical classes allow expanding the spectrum of controlled broadleaf weeds and increasing the effectiveness of suppressing weed species less sensitive to Magnum, listed above. Particularly noteworthy is the enhanced herbicidal effect of the tank mixture of Magnum and Dialen-Super on various species of ragwort, especially in cases of severe infestation. The problem of weed infestation by grassy weeds can be resolved by adding a grass herbicide as a third component in tank mixtures.
Accelerated visual manifestation of herbicidal action
Magnum is a systemic herbicide. It penetrates weeds through leaves and roots, is absorbed by them, and moves throughout the plant. The product halts cell division, leading to growth cessation and subsequent weed death. Visually evident signs of weed suppression by Magnum appear within 5–10 days under warm, humid conditions, and approximately 15–20 days under cold, dry weather. This fact often confuses agronomists: has the herbicide worked? Weeds stop growing and seem to 'freeze'. However, the product is still active, but the 'curling' or 'burning' effects typical of 2,4-D amine salts are not observed.
Tank mixtures can accelerate the appearance of visible herbicidal effects by several days. Components of Dialen-Super (dimethylamine salts of dicamba and 2,4-D acid) and Herbitoks (MCPA acid salts) exhibit faster growth-regulating effects.
A different scenario occurs with the Magnum-Tornado tank mixture applied to fallow land for cereal crops. More accurately, it is the Tornado-Magnum combination. The addition of Magnum helps ensure that weed death does not occur too rapidly (as in glyphosate-containing herbicide mixtures with 2,4-D), which does not hinder glyphosate penetration into roots and rootstocks of perennial root-seeding weeds. The biological effectiveness in this case is at least 93%.
Mitigation of residual effect risk
Demonstration trials also show that applying Magnum in tank mixtures with a minimum application rate of 4–5 g/ha reduces the risk of residual effects. Like many sulfonylureas, Magnum has restrictions on crop rotation: when applied at a rate of 8–10 g/ha on neutral or alkaline soils, sensitive crops such as sugar beet, rapeseed, buckwheat, sunflower, legumes, and vegetables cannot be sown the following year without preliminary assessment of potential phytotoxic residual effects using a bioassay. If replanting is necessary, only cereal crops should be sown on treated areas.
It has been proven that applying Magnum tank mixtures with Dialen-Super or Herbitoks, where Magnum is used at 5–7 g/ha, significantly reduces the risk of residual effects.
Reduced pesticide load and resource savings
Using tank mixtures not only slows weed adaptation to applied herbicides but also reduces herbicide load on treated areas and the environment (for example, the hectare application rate of each component in a tank mixture decreases by 20–50%). It is also important to save fuel and lubricants, reduce mechanical crop damage, and lower the cost of agrochemical treatments.
In 2004, the company "August" conducted demonstration trials of Magnum tank mixtures on flax crops in collaboration with the VNIIL Flax Institute. At the SXPK "Priborodny Plus" in Ustyuzhensky District of Vologda Oblast, experiments were conducted on flax of the Alexim variety according to the following scheme: 1) Magnum (7 g/ha) + Herbitoks-L (0.6 L/ha) + Myura (0.8 L/ha); 2) Magnum (5 g/ha) + Herbitoks-L (1.0 L/ha) + Myura (0.8 L/ha); 3) Magnum (5 g/ha) + Herbitoks-L (1.0 L/ha) + Myura (1.2 L/ha). Results showed that herbicide biological effectiveness was not less than 89–92%, and weed contamination of flax straw in all treatment variants was within GOST standards (0.6–4.0%), whereas in untreated plots it reached 38%. The yield increase of flax fiber compared to the control was 30.3–33.7 centners per hectare, and the profitability of weed control in flax crops was at the level of 156–173%.
Practical application results of herbicides, as well as data from research institutes, indicate that the weakest link among numerous factors affecting the effectiveness of tank mixtures remains the technology of their application. It has been established that during standard broadcast spraying, only 30–45% of the total amount of applied herbicides reaches the treated plants, while the rest is lost either through atmospheric drift (when droplet size is up to 75 microns) or by runoff of large droplets from leaf surfaces (over 300 microns). Therefore, it is necessary to use sprayers that ensure the maximum number of droplets with sizes of 80–300 microns.
The best results when using Magnum tank mixtures are achieved in early morning hours, with wind speed not exceeding 4 m/sec. Treatments should be conducted at least 4 hours before rainfall. It is not recommended to treat plants experiencing stress due to adverse conditions (meteorological factors: frost, hail; damage by pests, necrosis, etc.).
Water for preparing the working solution must be clean. It is prohibited to: prepare the working solution without first preparing herbicide stock solutions; add the measured amount of the herbicide directly into the container without first adding water.
When herbicide application coincides with insecticide or fungicide treatments, tank mixtures of herbicides with fungicides or insecticides are possible. The recommended sequence for adding plant protection products into the sprayer tank (through stock solutions), depending on their formulation: water-soluble granules → wettable powders → water-dispersible granules → concentrate suspensions → concentrate emulsions → water-soluble concentrates.
For multi-component tank mixtures, compatibility testing is required if there is uncertainty about the chemical compatibility of certain herbicides. In production conditions, a small test can be conducted in a standard 3-liter jar, dissolving components of the mixture in water at rates corresponding to their hectare application rates. Signs of incompatibility include stratification of the working solution, formation of foam, sediment, or flakes. Obviously, such mixtures are unsuitable for use. To test for phytotoxicity, it is best to conduct preliminary trials on a small plot.
