Natural enemies help to control the nuisance of the oak processionary caterpillar. Researchers have established that the use of birds and insects in the Drenthe village of Wapserveen has led to a decrease in the number of oak processionary caterpillars. That writes Nature Today Wednesday.
The researchers have been experimenting for four years with the use of natural enemies of the processionary caterpillar in Wapserveen. The natural enemies are attracted by the placement of bird’s nest, bat and insect boxes and the planting of flowers on the roadside.
The measures taken led for the third year in a row to a decrease in the number of oak processionary caterpillar nests at the trial location. An average of 1.7 litters per tree was counted in the 64 trees at the test location. In trees at nearby control sites, the researchers found more than 20 nests in some trees.
Not only were more nests counted at the control locations, these nests were also larger. It is estimated that more than 12,000 caterpillars per tree were counted at a number of locations. About five thousand trees where the natural enemies were active.
Of the birds, it turned out that the caterpillar in particular was eating a lot. Many insects were also observed at the test locations, including ladybugs, butterflies, beetles and various types of flies.
The researchers emphasize that the use of natural enemies ensures that the oak processionary caterpillar population remains manageable, but that the natural enemies cannot control the caterpillar.