Status Quo: Bird feeding and seed treatment for corn

The voices surrounding the issue of bird predation in German corn fields became particularly loud in 2020. Experts suspect a close connection with the mesurol ban [1].

Since spring, Mesurol, the insecticidal dressing used for many years in corn with a side effect against frit flies, pheasants and crows, may no longer be used. The reason for this is the decision of the EU Commission, which thus placed Mesurol on the red list of environmentally harmful inputs. The German Corn Committee e.V. (DMK) already reported in spring about future challenges due to the discontinuation of mesurol [2].

On June 3, 2020 [3], the DMK then noted increased reports of damage caused by frit flies, bird damage, and damage caused by game. In cooperation with the authorities, an attempt was made to establish a clear picture of the regionally heterogeneous damage caused by bird predation by means of a recording sheet. Also in the information service of the Lower Saxony Chamber of Agriculture, in the article: ” Corn – Damage due to bird damage and frit fly infestation” [4], a request was made for a survey of bird damage data in practice.

In practice, 2020 is always talked about an exceptional year for bird predation. Especially in relation to the complex behavior of crows.

Since the ban on mesurol, however, no conventional bird-repellent active ingredients have been available in Germany. Therefore, attempts are being made to approach the problem via fungicidal active ingredients 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 treated 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. Treated seed can nevertheless enter Germany via the Seed Marketing Act. The value added by the seed treatment companies is thus lost. An emergency authorization for Germany was issued at the end of 2019, but not drawn. Presumably due to the following measure for labeling on seed packages: “No spreading of treated seed in winds with speeds above 5 m/s.” To avoid unacceptable effects on non-target organisms, ensure that dust is already absent from seed packets and that additional abrasion of the dressing is minimized when the seed is mechanically stressed.

Furthermore, during the application of the treated seed, it must be ensured that the emission and transport of dust 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] Many 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.

First of all, however, it is important to distinguish feeding patterns. Our culprits the pheasant, the crow and the frit fly have their individual feeding behavior. The pheasant pecks 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 recognized by pecking holes in the soil, in which remains of the young plants can still be found. Damage occurs mainly when emergence conditions are poor and juvenile development is delayed. Crows, unlike pheasants, tear at seedlings to get at the grain. Torn plants are often lying around. Deep holes in the ground are less common here. In conjunction with plenty of organic matter and increased insect abundance, plants are sometimes pulled out to reach them. Consumption of whole plants up to the 4-leaf stage has been reported in some cases – the thesis of the crows’ need for water is at issue here. 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 leaf and yellow-white feeding grooves.

Current seed treatment equipment does not reach a mesurol level. The two close-ups 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 seed treatments are primarily intended to protect the ungerminated grain in the soil. Bird feeding incidents up to the two-leaf stage of the plant can be partly suppressed, but not excluded. Mesurol had a lasting effect in practice due to the “secondary repellent effect”, namely the intolerance for various animals and had a systemic effect up to the seedling. Currently available seed treatments can reduce – but not eliminate – cases of severe feeding damage by crows. Feeding damage often occurs when a stand is in a bird-preferred condition, as opposed to neighboring stands. Corn that has not yet broken through is not eaten as readily as corn in the three-leaf stage or larger, as is corn in the one- and two-leaf stages. In addition, areas with worm infestation are eaten more readily than those without protein. Areas near roost trees prefer to be eaten than exposed areas. No seed treatment can provide protection for the corn plant beyond the two-leaf stage. At 0.003 ml of seed treatment per seed. A drop of water has 0.05 milliliters, 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 damage pressure from crows for this year. This is explained by the high populations of the animals as well as by the dispersed sowing. Thus, there were always individual fields in the preferred growth area, which were then significantly damaged. In other years, seeding occurs in a much smaller window and at the same time the stands are in an endangered state. Therefore, the pressure on individual plots is not as great and is less noticeable.

SEEDFORWARD has its own developed bio-based seed treatment tested through the JuliusKühn Institute, Federal Research Institute for Cultivated Plants (JKI), with studies on repellenten activity. The JKI, the only German institute that conducts studies on bird predation in agriculture, has tested the product with pheasants. Results clearly show: the agent deters the birds. The JKI research results in cooperation with SEEDFORWARD can be found here.


[3] Ra/WR ZM 8-2020
[4] Landwirtschaftskammer Niedersachsen; Bezirksstelle Oldenburg-Nord, Nr. 18 / 19.06.2020 Hinweis zum Pflanzenbau und Pflanzenschutz für das Grünland und den Ackerfutterbau