In New Zealand, experiments on the potency of biodynamic tinctures for possum pest control were conducted – without any apparent success.

Brushtail possums (Trichosurus vulpecula Kerr), introduced from Australia in the last century, pose major problems for New Zealand’s farmers, as possums damage crops and spread a cattle disease. The repellent effect of five biodynamic tinctures on penned up possums was studied. Therefore, foraging behaviour, food consumption and body weight were evaluated. Additionally, the researchers monitored bait consumption from treated and untreated feeder stations in the field. No behavioural or repellent effects of the biodynamic measures were detected in any of the trials (see the publication cited below for further experimental details).

First trial:
It was tested whether materials obtained from burnt possum fur and testes had a repellent or disturbing effect on a total of three male and three female wild possums. The animals were acclimatised to captivity for two months and were kept in two mixed-sex groups of three animals each in two large outdoor pens (20 x 60 m). Four weighed portions of fruits and vegetables were placed at 10 m intervals in each pen. Treatments: A and B, two tinctures provided by Weleda New Zealand Ltd.; C, a tincture provided by a local farmer; D, a tincture provided by the Biodynamic Farming and Gardening Assoc.; E, a preparation produced by the researchers according to detailed instructions by the Biodynamic Farming and Gardening Assoc. Plain sand, wood ash tap water and water with 5% ethanol were used as placebos.

The tested materials were smeared over and around the food. The treatments were rotated each day in a random manner during a period of eight nights. The reactions of the animals were observed discreetly and the amount of food remaining after each test was reweighed. To avoid observer bias, the test was structured as a standard double-blind protocol.

Second trial:
Following the same procedure, two tinctures (A and B) were compared with an conventional egg/acrylic herbivore repellent.

Third trial:
The biodynamic tincture C was tested with wild possums. Fifty-eight bait feeders (plastic tubes containing 1.2 kg of pelleted cereal bait) were located at 50 m intervals. The feeders were kept filled during three weeks. The ground around half of the feeders (selected randomly) was sprayed 3-6 hours before dusk with 50-100 cm-3 of either the biodynamic tincture or the same volume of tap water in radius of 2 m. Bait consumption was evaluated in two successive nights.

Results:
Mean daily food consumption and body weight of the possums in the pens did not show a significant difference between biodynamic and placebo treatments. No repellent effects or other abnormal behavioural responses to the tinctures were observed. The mean bait intake of the wild possums was not affected significantly by treatments.

Reference:
Eason, C.T.; Hickling, G.J. (1992): Evaluation of a bio-dynamic technique for possum pest control. New Zealand Journal of Ecology 16, 141-144

Comment by biodynamic-research.net:
Regarding such experiments, in which different treatments were arranged at a distance of 10 and 50 m, respectively, it is very difficult to decide whether the preparations are effective or not. Describing this method, Steiner pointed out: “its influence irradiates far and wide...”. However, nobody knows in which radius it may work, that is at which distance the control treatment should be placed.