Status Quo: Bird feeding and maize dressing

This year, the voices around the topic of bird feeding in German maize fields were particularly loud. Experts suspect a close connection with the ban on mesurology [1]. Since spring, mesurol, the insecticidal dressing used in corn for many years with a side effect against frit flies, pheasants and crows, may no longer be used. The reason for this is the EU Commission’s decision to put Mesurol on the red list of environmentally harmful inputs. The German Maize Committee (DMK) already reported in spring on future challenges resulting from the loss of Mesurol [2] . On 03.06.2020 [3], the DMK then noted increased reports of damage caused by frit flies, birds and game. In cooperation with the authorities, a survey was carried out to obtain a clear picture of the regionally heterogeneous damage caused by bird feeding. In the information service of the Lower Saxony Chamber of Agriculture, the article “Maize – damage caused by bird feeding and infestation by frit flies” [4] also asked for bird feeding data to be collected in practice. In practice, 2020 is often talked about an exceptional year for bird-feeding. Especially with regard to the complex behaviour of crows.

Since the mesuro ban, however, no conventional bird repellents have been available in Germany. Efforts are therefore being made to address the problem through fungicides and their side effects, such as the active ingredient Ziram. On 03.03.2020, the magazine “Schweizer Bauer” [5] writes: “Various companies such as KWS Suisse offer corn seed dressed with Korit as an alternative. “Korit is only an alternative if the infestation with crows is low,” emphasizes Jürg Jost from UFA-Samen. He also refers to the safety data sheet. According to it, caution is advised when using Korit.” The active ingredient Ziram (contained in Korit/Duvit) is also already under fire and is only approved in other EU countries. However, through the Seed Marketing Act, the treated seed can still reach Germany. The added value of the seed processors is thus lost. An emergency approval for Germany was issued at the end of 2019, but not withdrawn. Presumably due to the following measure for labeling on seed packets: “Do not apply treated seed in winds exceeding 5 m/s.” To avoid unacceptable effects on non-target organisms, ensure that there is no dust already in the seed packets and that additional abrasion of the dressing is minimized when the seed is mechanically stressed.

In addition, during the application of the treated seed, it must be ensured that the emission and transport of dusts contained or produced by abrasion in the seeding equipment is prevented” .[6] In addition to the user risks already named, ziram is also said to be toxic to bacteria. [7] Not only in the field of fungicides, as current synthetic chemical alternatives, there are advances; also in the field of bio-based alternatives occur. The JKI Münster, which is responsible for repellent trials in Germany, is already working on biobased alternatives in various cooperation projects. A trend that seems promising due to the general development of synthetic chemical pesticide bans. [8] Numerous farmers had to struggle with these challenges this year. So it is important to take a closer look at the incidence of bird predation to better understand the situation.

But first of all it is important to distinguish between feeding patterns. Our culprits the pheasant, the crow and the frit fly have their individual feeding behavior. The pheasant chops rows of young plants out of the ground from the emergence to the 4-leaf stage. It prefers to eat the exposed grain. The pheasant can usually be recognised by hacking holes in the ground, in which remains of the young plants can still be found. Damage is mainly caused by poor run-up conditions and delayed juvenile development. In contrast to the pheasant, the crows tear at the seedlings to get to the grain. Torn plants often lie around. Deep holes in the ground are less common here. In combination with a lot of organic mass and increased insect occurrence, plants are sometimes pulled out to reach these. In some cases the consumption of whole plants up to the 4-leaf stage has been reported – here the thesis of the water requirements of the crows in the area is put forward. The secondary damage of the frit fly is more clearly distinguishable and is only visible from the 3-leaf stage. The infestation shows itself in the form of small holes in the leaves and yellow-white feeding channels. Figure: crow feeding in corn

Current pickling equipment does not reach a mesurol level The two close-up photos show the typical craters that are created when birds pull out entire plants, including the roots. The reasons for this are manifold and have not yet been researched in detail. Repellent stains are primarily intended to protect the ungerminated grain in the soil. Bird feeding occurrences up to the two-leaf stage of the plant can be partially suppressed, but cannot be excluded. Mesurol had a lasting effect in practice due to the “secondary repellent effect”, i.e. the intolerance for different animals, and had a systemic effect down to the seedling. Currently available staining equipment can reduce – but not eliminate – cases of severe feeding damage by crows. Frequently, feeding damage occurs when one population is in a state preferred by the birds, unlike neighbouring populations. Corn that has not yet broken through is, just like corn in the three-leaf stage or larger, not as readily eaten as corn in the one and two leaf stage. Moreover, areas infested by worms are more likely to be eaten than those without protein. Areas close to sleeping trees are preferred to open spaces. Protecting the maize plant beyond the two leaf stage cannot create a stain. With 0.003 ml mordant per grain. One drop of water has 0.05 millilitres, which is 10 times the amount.

If, nevertheless, a plant with a substance so repulsive to crows were brought to the field that it would no longer be touched, the farmer must ask himself whether he still wants to eat or feed this plant and whether he wants such substances on the field. The chambers in both Hanover and NRW confirm a conspicuously high pressure of damage from crows for this year. This is explained by the high populations of the animals as well as by the dispersed sowing. There were always individual fields in the preferred growth area, which were then considerably damaged. In other years, sowing takes place in a much smaller window and at the same time the stocks are in a vulnerable state. Therefore, the pressure on the individual surfaces is not so great and is less noticeable.

SeedForward has the specially developed bio-based seed treatment applied by the Julius Kühn Institute, Federal Research Institute for crop plants (JKI), with studies on the repellent effect. The JKI, the only German institute carrying out studies on bird feeding in agriculture, has tested the product with pheasants. The results clearly show that the product frightens off birds. Our biobased seed treatment MAISGUARD has has established a loyal and satisfied customer base in Germany and throughout the EU. “Our corn has developed well. Our neighbours, who used MAISGUARD, had no problems with birds,” says Hans Grötzinger from Bavaria. This can be explained not only by good professional arable farming but also by improved juvenile development, i.e. the so-called disease escape effects. The JKI research results in cooperation with SeedForward can be found here.

[3] Ra/WR ZM 8-2020
4] Lower Saxony Chamber of Agriculture; Oldenburg-Nord District Office, No. 18 / 19.06.2020 Note on plant cultivation and plant protection for grassland and arable forage production.

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