ABSTRACT
The seasonal evolution of Myzus persicae (Sulz.)was studied from 1977 to 1982, proving that it exists both in its holocyclical form, alternating host plants, and in its anholocyclical form, resulting in the possible survival of certain clones or species on secondary host plants. This explains the phenomena of resistance observed on citrus fruit trees. A total of 32 host plants – 29 of these being secondary hosts – were identified and listed.
On the peach tree the laying of winter eggs begins in the middle of October and ends at the end of December. Hatching starts at the beginning of January and finishes at the beginning of March.
Although the winged insects coming from secondary host plants attack the peach tree in a very limited manner, their offspring is incapable of reproducing.
Three periods of flight have been noted, but it is the winged species of the first flying period (February–March) that attack citrus fruit trees the most.
