When the foxglove or glasshouse potato aphid (Aulacorthum solani) feeds on sweet pepper plants, it secretes a toxic substance that disrupts plant development, often causing noticeable deformities in the growing tips. Interestingly, the location of the feeding damage does not determine where symptoms appear—aphid feeding on lower leaves can still lead to distorted growth in upper parts of the plant, including curled leaf margins and lumpy, irregular foliage. One of the first visible signs of infestation is the appearance of yellow patches on the lower leaves. In cases of severe infestation, this yellowing can become extensive and lead to leaf drop, further weakening the plant and reducing crop quality and yield.

Aphids, including the foxglove or glasshouse potato aphid (Aulacorthum solani), have a complex and highly adaptable life cycle that includes both winged and wingless adult forms, and a wide range of colour variation. In greenhouses, they reproduce mainly through parthenogenesis—unfertilized, viviparous females continuously give birth to live young, which are already developed nymphs. These nymphs begin feeding on plant sap immediately and grow quickly, moulting four times before reaching adulthood. Each moult leaves behind a white skin, making infestations easier to detect. When sexual reproduction occurs, eggs are laid that can survive the winter.

The wingless adults of A. solani are medium-sized (1.8–3.0 mm), oval, and somewhat squat in shape, with a shiny body that ranges from light yellow-green to brown-green. Their long antennae, often longer than the body itself, are banded with darker colours, and their legs are also long. Winged females (alates) are slightly larger (2.0–3.0 mm), with a yellow-green body, brown head, and dark thorax, and their abdomens show pale to dark bands. The species can complete either an anholocyclic life cycle (with no egg stage) or a holocyclic one (with winter eggs), depending on environmental conditions. Both cycles can occur on the same host plant, and the aphid can overwinter not just in greenhouses but also outdoors in protected locations, making control more challenging.

A distinguishing feature is the pair of dark green spots located at the base of the cornicles on the abdomen.

To prevent infestations of the foxglove or glasshouse potato aphid (Aulacorthum solani), it is important to maintain good cultural practices that reduce the aphid’s ability to establish and spread. Regularly inspect plants, especially new growth and undersides of leaves, for early signs of aphid activity such as distorted leaves or sticky honeydew. Keep plant material healthy by providing proper nutrition and watering, as stressed plants are more susceptible to aphid attack. Remove and destroy heavily infested plant parts to reduce aphid populations and prevent them from spreading. Avoid overcrowding plants to improve air circulation and reduce humidity, which can create less favourable conditions for aphids. Additionally, practice crop rotation and control weeds, which can serve as alternate hosts for the aphids. Finally, use physical barriers such as insect-proof screens on greenhouse vents to prevent aphid entry. Prompt action at the first sign of infestation is key to minimizing damage.

Several biological control agents can be used effectively to manage cotton aphid (Aphis gossypii) populations in greenhouses and protected environments. These beneficial insects and parasitoids target aphids at different life stages, providing natural and sustainable suppression.

Chrysopa (green lacewings) are generalist predators whose larvae consume large numbers of aphids during development. Each larva can eat hundreds of aphids, making Chrysopa a strong choice for hotspot infestations or preventative releases.

Aphidalia, containing Adalia bipunctata (the two-spot lady beetle), is another powerful aphid predator. Both larvae and adults actively seek out aphid colonies, including those hidden deep within the plant canopy, and feed voraciously.

Aphided includes Aphidoletes aphidimyza, a predatory midge whose larvae feed directly on aphids. After adults lay eggs near aphid colonies, the emerging larvae efficiently reduce aphid numbers, often collapsing infestations within weeks under optimal conditions.

For parasitic control, Ervipar (Aphidius ervi) and Aphilin (Aphelinus abdominalis) are tiny parasitoid wasps that attack aphids. Ervipar species parasitize the foxglovee aphid, helping to suppress the aphid population by developing inside the hosts and eventually killing them.

Together, these beneficials offer complementary modes of action: Chrysopa, Aphidalia, and Aphidend directly prey on aphids, while Ervipar and Aphilin parasitoids provide biological suppression through parasitism. Selecting the appropriate combination depends on crop type, climate, infestation severity, and presence of other pests. Early or preventative introductions combined with careful crop monitoring help maintain aphid populations at manageable levels, reducing the need for chemical controls.