The aphids (Figures 1 to 4) have quite a complicated life cycle, with the possibility for adults of some species change host in winter. We find eggs, founders of populations, adults, among them, winged viviparous females or not, and winged males. The length of the cycle varies depending on the species, the nature of the host plant and its condition, and climatic conditions.

• Forms of conservation and / or alternative hosts

It is often the eggs, laid in particular on many weeds at the approach of winter, which allow these insects to overwinter. They can, of course, survive under heated shelters on existing crops, in the form of viviparous females in particular.

• Stages of development

The eggs laid on various hosts, herbaceous or woody, hatch and give rise to founders. Subsequently, over a long period of time, viviparous females are found in the colonies.

Young larvae form, which immediately feed on the sap and molt 4 times before giving birth to the adult. White moults (exuviae) on vegetation indicate the presence of aphids in the crop. The adults are winged (1 - figure 5) or not; in the latter case, we speak of “wingless” individuals (2 - figure 5). Each individual can give birth to 40-100 offspring depending on the host and climatic conditions in particular.

Larvae and adults, often present on the underside of the leaf blade, feed through their rostrum. The excess sugar contained in the sap is rejected in the form of honeydew.

• Dispersion in culture

A few plants scattered throughout the crop on which aphid colonies quickly gain importance constitute the first outbreaks. First wingless, aphids start by visiting neighboring plants. As soon as the adults appear (during outbreaks), they disperse in the crop or in nearby plots. Plants and workers can contribute to their spread.

• Favorable development conditions

These insects appreciate mild temperatures and summer shelter conditions.

Last change : 04/19/21