Conservation biological control is a method to protect crops against pests. It consists in managing these pests by protecting and promoting crop beneficial invertebrates naturally occuring in the environment, by maintaining or developing their “resource” habitats. This control method is part of an integrated protection approach, as an agro-ecological variation of biocontrol par excellence, involving changes in the environment and/or practices.
A crop can act as a habitat for part of the beneficial invertebrates’ cycle (source of food and hosts/prey to lay eggs). However, in order to complete their entire life cycle, these organisms require habitats which offer additional resources (of the same nature) and complementary resources (of a different nature) than those provided by crops.
Conservation biological control therefore consists in encouraging these natural auxiliaries by conserving and creating, around the plots to be protected, the elements (hedges, ditches, fallows, flower strips, etc.) providing the resources (pollen, nectar, substitute prey and hosts, micro-habitats …) needed for their entire life cycle. Thus, in case of an attack on the crop, the beneficials already present in the environment are able to quickly use the emerging pest population as a resource. For instance, adults of Episyrphus balteatus (Diptera, Syrphidae) are flower visiting insects(feeding on pollen and nectarr, while larvae are aphid feeding predators. Thus, any spontaneous vegetation or voluntarily sown vegetation which bring these resources will favour their presence around and in the plots, where the aphid outbreaks will then be more easily controlled.
By requiring the conservation or restoration of the beneficial invertebrates’ natural habitats, this control method favours a more eco-friendly and sustainable agriculture.