The natural control of the apple-grass aphid, Rhopalosiphum insertum, with remarks on the control of apple aphids in The Netherlands in general

Abstract

In this paper the apple-grass aphid is stated to be the only aphid in the Netherlands that regularly hibernates in large quantities in commercial apple orchards. The possible reasons for this are discussed. Abiotic factors, especially rain, hail, wind and ice formation in early spring, are by far the most important in drastically reducing the numbers of fundatrices. Of the biotic factors, ladybird beetles in spring may be important. The apple-grass aphid parasite, Monoctonus cerasi, may reach high peaks of parasitism during some periods in the season; in comparison with abiotic factors, however, its effect does not seem to be very important. The life history of the parasite seems to be well adapted to that of its host. It is suggested that the winter wash against apple aphids might be omitted, with eventual application of a spring spray in certain circumstances. In most cases this spray will only be necessary if the rosy apple aphid is present. © 1966 Koninklijke Nederlandse Planteziektenkundige Vereniging.