Direct damage

Direct damage

The kinds of damage inflicted directly result either from the removal of sap by the aphids or the toxicity of their saliva

Direct damage due to sap removal

This is related simply to the extraction of the plant’s nutrients. The aphids, being piercing and sucking insects, feed themselves by taking up and absorbing their host’s sap. This weakens the plant, which grows poorly, wilts and can dry out completely. The damage starts to show, depending on the stage of the plant, by diminished growth, poor fructification (aborted fruit) or a decrease in the number of seeds (yield loss). The damage will depend on the duration of the aphids’ presence and their numbers on the plant for each stage of development, also on the plant’s level of sensitivity to these insects.

Direct damage due to saliva secretions

Aphid saliva exerts an irritant, toxic action: the plant reacts to the piercing for food and to the presence of saliva, often in a specific way. It may be leaf deformation, whereby leaves fold up and wrinkle, roll up, shrivel, show an embossed effect, crinkle, thicken, blister, swell, become corrugated, with or without colour change. Sometimes shoots become stunted and shrivel, twist, the internodes are short, flowers abort and dry up, the leaves fall, fruit look dented, hardly grow in size and lack flavour. Moreover cankers appear on branches or roots, galls form on leaves or stems.

Aphis fabae
damage on artichoke

Aphis gossypii
damage on courgette

Brevicoryne brassicae damage on rape 

Myzus cerasi
damage on cherry

Aulacorthum solani
damage on Calceolara

Brachycaudus helichrysi damage on sunflower

Dysaphis plantaginea damage on apple

Pemphigus spyrothecae gall

Modification date : 07 February 2023 | Publication date : 02 December 2010 | Redactor : Evelyne Turpeau, Maurice Hullé, Bernard Chaubet