Thinning with Darwin
Thinning, i.e. removing excess flowers and fruit, improves fruit quality and increases the degree of flowering activity in the following year. Thus, alternans (periodicity) is prevented or at least minimized.
Alternance is the variation in fruit yield in the biennial rhythm of fruit trees, particularly cultivated apple and pear trees, but also olive trees and plums, often caused by weather effects.
The Darwin device was developed in 1990 by horticulturist Hermann Gessler from Friedrichshafen. It works by means of a vertically rotating spindle on which long plastic cords are attached. These reach into the treetops and knock down soft plant parts such as leaves and flowers.
Fruit trees should flower abundantly, because the flowers are the basis for a good harvest. As soon as it is clear that there are too many flowers, we start thinning them out.
The best time to use the Darwin machine is during full bloom. The royal flower and two or three other flowers should be open.
The earlier we thin out, the more flowers the tree will produce for the next year and the better the fruit will develop. Thinning is always worthwhile in fruit growing. The fruits reach the size and coloration required by the market. They taste more intense because they contain more sugar and acid. The fruits are more suitable for storage and the flesh is firmer. Excessive fruit loads place a heavy burden on young plants. Thinning promotes crown development, reduces branch and crown breakage, and prevents premature greying of the trees.
