This preventive measure contributes to favour the presence of auxiliary insects and thus, help control pests. A lot of species of natural enemies need sources of foodstuff (pollen, nectar, arthropods…) that can be provided by the establishment of habitats of vegetation near the crops.
The implementation of hedges and flower strips in the borders of plots or in free spaces between crops, allows creating spaces without treatments that act as a biological reservoir.
These hedges serve as refuge for auxiliary fauna at the end of the vegetative cycle. It is interesting to combine different vegetal species, with distinct flowering periods, in order to obtain a more diversified entomofauna. Besides the fact that hedges are an accommodation for the auxiliary insects, they act as a physical protection by reducing the effects of the wind, erosive effects, etc.
Figure 2. Installation of fences and in plot’s borders
With regard to flower strips, they are more attractive than the crop so higher levels of pests and auxiliaries are observed in them. Some aspects have to be considered when selecting the strip: the number of flowers of the specie, the production of pollen, the flowering period… This flowering period has to be suitable for the crop cycle and, as with the hedges, it is interesting to combine different types of species such as to increase the biodiversity.
Figure 3. Flower stripe with various vegetal species
Banker plants are specially used in greenhouses and they contribute to the development of auxiliary fauna by providing them the required resources (other insects, pollen, nectar…) which cannot be found in crops. These natural enemies disperse into the crop and help to control other pests.
Additionally, the installation of nest-boxes is also common to boost predatory birds (owls, kestrels…). This preventive measure consists in the placing of nest-boxes in posts or buildings, in areas where there are problems with voles and other rodents.
Implementation of this measure in LIFE AGROintegra project:
Flower stripes have been established in different trials with some horticultural crops (chard, borage and thistle) and in the demonstration carried out in tomato crop and broccoli. Some of the vegetal species that were used in the flower stripes were: Cosmos bipinnatus, Cosmos sulphureus, Zinnia elegans, Calendula officinalis, Coreopsis tinctoria, Helianthus annus, Centaurea cyanus…
Figure 4. Flower stripes established in horticultural crops
The presence and abundance of auxiliary fauna in fences and flower stripes has been monitored, identifying Families and Orders. This task has been done by the University of Navarra in the framework of a doctoral thesis made by Xabier Elizalde Gaztea “Bandas floridas e insecticidas ecológicos en cultivos hortícolas de Navarra: estudio de su eficacia y sus efectos sobre el control biológico de plagas”.
Besides, in Sartaguda and Baretón trees and fences have been implemented as part of the IPM strategy.
Figure 5. Nest-boxes to boost predatory birds