Other than the effects exerted by abiotic factors (wind, rain, heat, cold and so on), natural antagonists limiting aphid populations are essentially insects. The arachnids probably also play an important role. Birds too play their part, among which partridges and blue tits can be significant predators. In the realm of fungi, some can induce full-blown epizootics in aphid colonies.

Following classical definitions, the following types of entomophagous organisms can be distinguished:

• predators need several kinds of prey for them to accomplish their cycle,
• parasitoids generally develop on just one host, often inside it, and which they kill once their larval development is complete
• hyperparasitoids develop at the expense of primary parasites present in the aphids
• pathogens disease-generating micro-organisms (fungi, bacteria, viruses and so on).

Coccinella septempunctata	Aphelinus abdominalis	Asaphes sp	Erynia neoaphidis