Cover crops for pest control in Mediterranean citrus orchards (BIOFRUITNET Practice Abstract)

Summary

Cover crops benefit both natural enemies and soil composition, while supporting pest control. They offer shelter and food to natural enemies (predators, parasitoids and phytoseiids) and improve soil resilience to extreme weather events, such as heavy rains and organic matter.
Practical recommendation
• Vegetation covers can be spontaneous or sown (cover crops). Even if sown, they will tend to become natural cover over the years (Picture 1c). The Mediterranean shrub flora is varied and can be in flower most of the year.
• Cover crops can be:
o Mixed grasses (Picture 1a) which are drought resistant, conserve soil and increase organic matter (e.g., Festuca, Lolium, Bromus…)
o Leguminous mixtures (Picture 1b) which fix nitrogen and increase soil fertility. Widely used in organic farming (Trifolium sp., Alfalfa...).
o Mix legumes and grasses to combine the benefits of both above.
o Mix of flowers (Picture 1d) using local plant species that flower most of the year.
• Sow coverer crops in spring or autumn. Sowing rate of 25-50 kg/ha. Temper or water the soil after sowing; otherwise, the ants will carry away the seeds. Sometimes it is necessary to reseed the following season.
• Maintenance (or tillage): Mow about 2-4 times a year (depending on rainfall intensity). With a mower (Picture 2) or a mulcher (at a maximum height of one inch).