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In Cooperation with Bavarian Institute for Viticulture and Horticulture, Centre of Apialogy an expert appraisal of the products PIGROL Beutenschutz-Lack  (lacquer)und PIGROL Beutenschutz-Lasur (wood glaze) respective bee compatibility was done. The following excerpts are a summing-up based on the final report of this project.


Laboratory tests

In laboratory tests bees were brought in contact with the products under controlled circumstances. These tests were performed in order to figure out the mortality rate and to observe and document the behavior of the bees.



(picture source: LWG Veitshöchheim)



Life span tests

Initially, the coatings were tested on their compatibility with bees in cage tests. Test cages made of high-grade steel (fig. 1) were filled with 50 young bees each and the back panel of each cage was equipped with a wooden board (5 x 7 cm) (fig. 1). The wooden boards had been treated with the products according to the manufacturer´s information. Cages with untreated wooden boards served as checking purposes as well as cages with wooden boards that had been coated with pure bees wax. One test group received boards which had been treated with a weak insecticidal coating (negative control).


For each treatment variation ten cages were set and observed over a three week period. The cages were set up and supplied with food "ad libitum" in an incubator at 27°C. The mortality rate was recorded at two day intervals by counting the number of dead bees in the cage. Dead animals were removed. After nine days the average mortality rate in all cages was below 5 %. At this time of the test no statistical differences could be observed.  Due to the low mortality rate the observation time was extended from 21 to 25 days, were significant differences were noticeable. The mortality rate after 21 and 25 days was much lower in the cages with PIGROL Beutenschutz-Lasur compared to the cages with the negative control, the different results in cages with PIGROL Beutenschutz-Lack have to be statistically analyzed.


As a conclusion it can be said that the death rate of the testing cages lacquer (Beutenschutz-Lack) and glaze (Beutenschutz-Lasur) were never significant higher than in the control, negative control and bee wax cages.



(picture source: LWG Veitshöchheim)



Contact test

In a contact test the bees were applied a small amount of the products directly on the thorax. A drawing pencil served as a control which is also used in marking the queens in queen bee breeding. The negative control complies with the same product as the durability test.

In this experiment 20 young bees were first set in cages and kept in an incubator for 24 hours. Every test element consisted of five cages with 20 bees each. The following day, the insects received their individual applications on the thorax. In order to fix the application it was necessary to numb the bees temporarily by cooling. Otherwise the animals would clean themselves whereby the moist paint would agglutinate their antennas and wings. Following the application the bees were put back into the cages and observed in analogous manner to the durability test. However, the observation time in this test was reduced to 15 days as a reduction of the group size normally affects the lifespan of the animals. To record the effect of the cool-down, an additional group of bees was set in a cage in which they had only been "cooled-down". Animals, which died in contact tests, died mainly in the first 72 hours after application. In all test cages, with exemption of the negative control, the death rate was below 50 percent after 15 days. The mortality in the test element lacquer (Beutenschutz-Lack) complies with that on usage of a drawing pencil. Significant differences between lacquer (Beutenschutz-Lack) and the other test cages were only noticeable compared to the negative control The negative control showed a higher death rate (more than 80%).


The mortality rate in the test element glaze (Beutenschutz-Lasur) is slightly enhanced, although clearly below the negative control. The differences to the negative control are significant after 72 hours, but not after 15 days. Compared to the untreated control cage the mortality in the cages with the glaze (Beutenschutz-Lasur) is slightly higher, but not significant.


As a conclusion it can be said that the application of both coatings - glaze (Beutenschutz-Lasur) and lacquer (Beutenschutz-Lack) - to the thorax of the bees lead to the same effect as a marker normally used for marking queen bees.




(picture source: LWG Veitshöchheim)



 Outdoor test

For the outdoor test untreated beehives had been furnished with both coatings. To clearly establish possible effects the hives were painted on the inside as well as on the outside against the Apicultural Practice (fig. 5). For observation purposes hives without coating were used. These hives were occupied with young bee colonies at the end of September 2010 and equipped with death-traps. These death-traps allowed the registration of the mortality rate in the bee colony. The traps were controlled for several weeks during autumn 2010. There were no difference in mortality of bees in the coated and the untreated bee hives In spring 2011 possible effects on the brood were checked in which the brood mortality rate was determined. Therefore, transparencies protocols were made for every colony. In the course of the transparencies protocols at least 100 brood cells were individually marked and the development was observed until shortly before hatching. Neither at the beginning of the tests nor at controls in spring any differences could be noted regarding amount of bees or volume of brood nest (amount of brood cells).


Final summary of the tests

The tested products Beutenschutz Lack (lacquer) and Beutenschutz Lasur (glaze) showed neither in the laboratory tests nor in the outdoor tests any negative impact on honey bees. In the test to live spans no differences could be evaluated compared to untreated controls.


A direct application to the thorax of the bees lead to an average death rate comparable with a marker used in marking queen bees.


Bee colonies, which lived in coated hives in step with actual practice of beekeeping showed the same colony growth as bee colonies kept in un-treated hives. Neither a higher death rate nor a higher mortality of brood arised.




Download of the complete test summing-up: