Josep A. Jaques Miret

We have established three different plots of 1.0 hectare each with a twin design: 0.5 ha of conventional cropping practice, and 0.5 ha of enhanced integrated pest management (IPM) practices. They are all located a few kilometers away from each other, and about 40 km North West of the city of Valencia. In the enhanced IPM plots, we have established a grassy cover crop and are cultivating different aromatic companion plants: salvia, oregano, rosemary and savory. We have opted for a twin design, because it remains the soundest way to explore the differences between the plots. In one of these plots, we are including all these ecological infrastructures, in order for us to compare.

Throughout Spain, bee hives aren’t placed in the vicinity of citrus groves during full bloom. It’s meant to protect our selected citrus trees, which produce seedless fruits. Citrus trees are self-pollinating, but having bees during the blooming season increases the risk of cross-pollination with other citrus trees, and leads to the appearance of seeds in the fruit. Spain is one of the largest exporters of fresh citrus fruit, and seedless fruits are more appreciated by consumers, and sold at a higher price.

Spanish citrus growing areas are mostly made of small-size landholdings, and we wouldn’t necessarily worry as much about cross-pollination if fields were larger. As part of PLANT-B, we are the only research partner not interested in enhancing bee presence in the orchards during the main blooming period. Our plan is to observe the companion plants. If we find out that the blooming of these aromatic plants coincides with the citrus trees’ blooming season, we can do one of two things: either we prune these plants when the citrus blooms, or we could rid the field of these plants, and only keep the ones whose flowering time does not coincide with the citrus.

Even though we are not interested in bees during the citrus’ main blooming period, we could imagine having them in and around the field, except at that time. Those aromatic plants are interesting because they could serve as alternative food for natural enemies such as parasitoids, which feed on nectar. These species could feed on these plants to collect nectar and pollen during long periods not overlapping with citrus blooming. Outside of bees, the other thing we need to keep in check is whether these plants can be used as a reservoir for pests.

Our objective is to prove whether these companion plants could be a useful addition within this ecological infrastructure. Not for pollination, but for biological control. Very simply put, the ecological service that we want to provide and increase is biological control. So we'll see if this is the case.