**3.1 In search of camouflage**

The aim of the first experiment in coloring, which took place in March 1981, was to get a hue close to the soil color, this way, camouflaging the wheat seeds, making them imperceptible to birds. An adequate coverage should effectively camouflage the seeds without affecting germination, having low cost and being non-toxic. On the first experiment with color, we used several different shades of the commercial product called Powder Chess ® (hereinafter: powder dye), commonly used in paintings. This product was applied directly to the seed without use of adhesives.

The chemical composition of this dye was based mainly on iron oxides (FeO) in red and yellow colors, and silicatate colloidal sulfur of the FeO in blue color, these being the three colors forming the mixtures (camouflage).

The proportions in grams of the pigments, according to the colors of soil, ranged as follows: i) 15 red, 4 yellow: 5 blue, ii) 15 red: 14 yellow: 5 blue, iii) 15 red: 4 yellow: 15 blue. The analysis of the camouflage covers was done visually, comparing them with soil samples from Londrina (PR).

Results showed that, as proportions of each pigment were varied, different tones could be obtained. This fact contributes positively to the camouflage of seeds, enabling it to create coatings with colors that can approach the tone of croplands, from light sandy soils to darkreddish clayey ones. For example, to color 110 kg of wheat seeds according to a sample of dark red latosol from Londrina-PR, it took 2.4 kg of mixed colors. The individual quantities of dye to 100 kg of seed were: 1.5 kilograms of red pigment, 0.40 kg of yellow pigment, and 0.50 kg of blue pigment.

## **3.2 Camouflage improvements**

376 Pesticides in the Modern World - Risks and Benefits

The high mortality rates noted in Brazil are equivalent to existing findings (Eisler, 1985; Agriculture Canada, 1993; Mineau et al., 1999; Mineau, 2005) regarding the potential impact

Given these findings, research must be intensified to evaluate the magnitude of the impact that pesticides are having on Brazilian fauna, since these application methods and formulations have been banned in developed countries, but they are still used in Brazil, and probably in other Latin America countries, on large commercial scales, with government permission. The Brazilian Federal Government should be pressured, since the continued use of carbofuran and Rhodamine B is in conflict with Brazilian Law (Number 7802, July 11,

Fig. 13. Seeds treatments tested in the second trial of the removal experiment: camouflaging with industrialized liquid dye (above, left), camouflaging with powder dye (above, right), aposematic mid-blue seed (center), yellow natural corn (below, left), rhodamine B treated

The aim of the first experiment in coloring, which took place in March 1981, was to get a hue close to the soil color, this way, camouflaging the wheat seeds, making them imperceptible to birds. An adequate coverage should effectively camouflage the seeds without affecting germination, having low cost and being non-toxic. On the first experiment with color, we used several different shades of the commercial product called Powder Chess ® (hereinafter: powder dye), commonly used in paintings. This product was applied directly to the seed

carbofuran exposure can have on wild birds.

seeds (below, right).

**3. How to do camouflaged seeds?** 

**3.1 In search of camouflage** 

without use of adhesives.

1989) because they may cause environmental damage.

Searching for the development of camouflage techniques of seeds treated with syrup of carbofuran, which would provide color and texture similar to the ground, in order to prevent wild birds to recognize them, experiments were carried out in two phases to the selection of appropriate material. Later, the ingredients used for camouflage were selected, according to criteria relevant to seeds germination and their treatment on the machines that apply the Carbofuran syrup. This syrup, composed of Carbofuran, Rhodamine B had a commercial commonly used concentrated suspension of 350 g/L (hereinafter: carbofuran syrup).

From all the materials tested, those which did not showed favorable characteristics to the staining process were:


The items which initially showed favorable characteristics to the staining process were:


#### **3.2.1 Material selection for seeds camouflage: phase 1**

This phase started in January 2002 aimed at testing different materials to be possibly used in the process of concealment of the seeds. Features like the coloring capacity of the pigments, its viscosity, seeds agglutination during the treatments, homogeneity and cover resistance were observed, and so the materials deemed suitable were selected for phase 2.

Camouflage of Seeds, a Control Method of the Bird Mortality in Grain Crops 379

The mixture of dry soil sieved with acrylic glue and water covering the seeds presented an adequate concealment from the ground as the main element of camouflage. The powder dye mixed with carbofuran syrup and water; and the mix of soil, water, and glue; were the

i. soil as a secondary element (untreated seeds): 1 kg of brown powder dye, 2 l of

ii. soil as a secondary element (previously carbofuran syrup-treated seeds): 0.3 kg of brown powder dye, 0.7 kg of red powder, 2.6 kg of yellow powder dye, 0.2 l of acrilic

i. Determine the ideal minimum proportions of pigments in order to obtain a homogeneous covering of the seeds and complete disappearance of the reddish color

ii. Determine the minimum proportions of pigments in order to achieve coloring shades

iv. Determine the minimal amount of glue, necessary to the best pigment adhesion to the

v. Test the possibility of using soil as the main element or secondary one in the

Corn and pigments (powder dye) were weighed on an analytical balance. Corn seeds were divided into portions of 100 g. Powder dye in brown, yellow and red colors, were divided

In each test (i.e. for every mixture type), a portion of corn (100 g) was poured into a plastic cup. In a separate bowl, the material to be tested was mixed up, adding soon after this mixture to the corn. The closed vessel was shaken to simulate the machine where seeds

When the sifted soil was used, first the seeds received the coverage mentioned above, after, while they were still wet, they received a layer of dry soil. Then, it was added water and glue, and more servings of dry ground, until it reached the proper coverage. Next, the seeds

Treatments (or prototypes) of camouflaging obtained with the ingredients that gave the best

This experiment, conducted in January 1982, aimed to assess whether the pigments used in the process of concealment of seed germination are inhibitors of wheat germination, with or without the presence of carbofuran and the fungicide that is applied in the comercialized

treatments that showed the best colouring results, and the proportions were:

carbofuran syrup, 4 l of water, 1 l of glue, 30 kg of sieved soil;

caused by the Rhodamine B, present dye in the carbofuran syrup.

seeds, in the case of seeds already treated with carbofuran syrup.

were placed in plastic containers for dry and then received visual analysis.

results (Figure 14) were evaluated for germination and can be found in the Table 1.

iii. Determine the minimal amount of water to be added to the mix.

**3.2.2 Material selection for seeds camouflaging: phase 2**  This phase, conducted between February and March 2002, aimed to:

glue, 3 l of water, 20 kg of sieved soil.

next to the various shades of the soil.

into different portions from 0.1 g to 2.0 g.

**3.3 Camouflaged seeds in germination tests 3.3.1 Seeds camouflaging with powder dye** 

normally receive carbofuran syrup.

Eight treatments were established:

i. Red powder dye. ii. Blue powder dye. iii. Yellow powder dye.

seeds.

camouflage of seeds.

The material was tested in phase 1: white plaster, calcium carbonate, powder dye, liquid dye, ink (synthetic pigment concentrate), white acrylic glue, dolomitic limestone with magnesium (Hidrax ®) and carbofuran syrup.

In each test (i.e. for every mixture type), a portion of corn (100 g) was poured into a plastic cup. In a separate bowl, the material to be tested was mixed up, adding soon after this mixture to the corn. The closed vessel was shaken to simulate the machine where seeds normally receive carbofuran syrup.

Experiments were carried out by varying the proportions of material used, resulting in 75 samples of treated seeds. Samples that showed notable coloring failures were excluded. From 75 experiments, 20 samples of shades of different colors were obtained, going from dark brown to lighter shades, varying also the covering texture of the seed by the mixtures.

As for colourings, the best results were obtained with the following proportions: 2 to 4 kg of dye powder to 100 kg of seeds, using 2 l of carbofuran syrup and adding 2 to 3 l of water.

Particularly for the red latosol, the best results in coloring tests were shades tones achieved by mixing the following proportions of powder dye (for 100 kg of seeds, using 2.0 liters of carbofuran syrup): yellow powder (2.6 kg), red powder (0.7 kg), brown powder (0.4 kg), totaling 3.7 kilograms of dyes.

These proportions resulted in a medium brown shade. In order to obtain similar shades of dark or medium brown, the ratios mentioned above must be changed. For a darker ground, it is necessary to use more brown and less yellow, for a lighter soil, one should use more yellow and less brown.

The use of soil as the main element to camouflage corn seed showed good results for colour and texture. The proportions that showed the best results in the laboratory were: 6 l of water, 0.5 l of acrylic glue, 2 l of carbofuran syrup, 50 kg of sieved soil. The better amount of water to 1 to 2 kg of powdered dye was 1.5 to 2 l (using 2 l of syrup) to 100 kg of seeds. The amount of acrylic glue that brought satisfactory results was 0.2 l per 100 kg of treated seeds with 2 l of syrup.

Fig. 14. Prototypes of camouflaged seeds, during the experiment in color and texture. These treatments were selected for the germination experiment

The material was tested in phase 1: white plaster, calcium carbonate, powder dye, liquid dye, ink (synthetic pigment concentrate), white acrylic glue, dolomitic limestone with

In each test (i.e. for every mixture type), a portion of corn (100 g) was poured into a plastic cup. In a separate bowl, the material to be tested was mixed up, adding soon after this mixture to the corn. The closed vessel was shaken to simulate the machine where seeds

Experiments were carried out by varying the proportions of material used, resulting in 75 samples of treated seeds. Samples that showed notable coloring failures were excluded. From 75 experiments, 20 samples of shades of different colors were obtained, going from dark brown to lighter shades, varying also the covering texture of the seed by the mixtures. As for colourings, the best results were obtained with the following proportions: 2 to 4 kg of dye powder to 100 kg of seeds, using 2 l of carbofuran syrup and adding 2 to 3 l of water. Particularly for the red latosol, the best results in coloring tests were shades tones achieved by mixing the following proportions of powder dye (for 100 kg of seeds, using 2.0 liters of carbofuran syrup): yellow powder (2.6 kg), red powder (0.7 kg), brown powder (0.4 kg),

These proportions resulted in a medium brown shade. In order to obtain similar shades of dark or medium brown, the ratios mentioned above must be changed. For a darker ground, it is necessary to use more brown and less yellow, for a lighter soil, one should use more

The use of soil as the main element to camouflage corn seed showed good results for colour and texture. The proportions that showed the best results in the laboratory were: 6 l of water, 0.5 l of acrylic glue, 2 l of carbofuran syrup, 50 kg of sieved soil. The better amount of water to 1 to 2 kg of powdered dye was 1.5 to 2 l (using 2 l of syrup) to 100 kg of seeds. The amount of acrylic glue that brought satisfactory results was 0.2 l per 100 kg of treated seeds

Fig. 14. Prototypes of camouflaged seeds, during the experiment in color and texture. These

treatments were selected for the germination experiment

magnesium (Hidrax ®) and carbofuran syrup.

normally receive carbofuran syrup.

totaling 3.7 kilograms of dyes.

yellow and less brown.

with 2 l of syrup.

The mixture of dry soil sieved with acrylic glue and water covering the seeds presented an adequate concealment from the ground as the main element of camouflage. The powder dye mixed with carbofuran syrup and water; and the mix of soil, water, and glue; were the treatments that showed the best colouring results, and the proportions were:

