Aphid (superfamily Aphidoidea)

Size:

• 1 to 7 mm depending on the species

Look:

• Soft body, often teardrop-shaped
• Colors vary depending on the type: green, black, red, yellow, grey
• Mostly wingless; winged forms occur where population density is high.
• Two tube-like extensions (siphons) on the abdomen
• Long antennae, sucking mouthparts

Way of life:

• Colony-forming on host plants
• Reproduction both asexual (virgin birth) and sexual
• Several generations per year, active indoors year-round
• Winged animals ensure rapid spread

Reproduction:

• Females give birth to live offspring (viviparous)
• Under optimal conditions, several generations are produced per month.
• Eggs are laid in late autumn for overwintering.
• Combination of parthenogenesis and sexual reproduction depending on the season

Infestation sites:

• Undersides of leaves, shoot tips, flower buds
• Stems, leaf veins, young shoots
• Ornamental plants such as roses, hibiscus, chrysanthemums
• Useful plants such as lettuce, tomatoes, beans, fruit trees

Nutrition:

• They suck plant sap from vascular tissue.
• Excretion of sugary honeydew
• This promotes fungal growth (sooty or black fungi)
• Weaken the plant by depriving it of nutrients

Behave:

• Hardly mobile, they remain stationary on preferred parts of the plant.
• Winged animals fly to new plants when space is limited or they are stressed.
• They often live in symbiosis with ants, which use the honeydew and protect them.
• Visible through curling, deformations, or sticky leaf surfaces

Virus transmission:

• Transmitted by more than 100 plant viruses, for example in vegetables or fruit
• Particularly problematic in professional plant production
• Viruses are transmitted from plant to plant when they suck sap.

Plant damage:

• Deformed leaves, stunted shoots
• Slowed growth, reduced flowering or yield
• Secondary infection by fungi or viruses
• Mass reproduction without control

Ant population:

• Ants promote aphid infestations by protecting them from predators; in return, the ants receive the honeydew as food.

Biological control:

• Encourage natural enemies such as ladybugs, lacewings, and parasitic wasps
• Apply biological agents early and repeatedly

Early detection

• Visual inspection of leaves and inside the plants