A large number of the Nadorcott late season mandarin producers have adopted the strategy of covering their crops during flowering weeks, with anti-insect netting, in order to avoid cross pollination with neighbouring varieties and so that the fruit doesn’t contain annoying pips (seeds), that reduce their commercial value.
It is well known that pollination between flowers of different hybrid mandarins, or between mandarins and clementines, causes the production of pips in the fruit of varieties that do not normally have them if cultivated in isolation.
The netting used is similar to the one placed on many fixed installations that can be seen throughout the agricultural geography. Sometimes on Nadorcott mandarins and other varieties, also on kiwis and other crops, and its purpose is not only to avoid cross pollination, but also to protect against possible hurricane or hail damage.
However, a fixed installation requires a substantial investment, it requires technical projects and local permits, and, according to some expert opinions, represents an action that also has its disadvantages, such as maintenance and the fact that during the winter season there is too much humidity in the interior, which is not always desirable and suitable for the development of the crop and its suitable harvest.
Despite this, isolating Nadorcott trees also during flowering has become the most suitable option to ensure the mandarins are seedless. Something basic, essential, to validate their commercialisation among clients. On top of this, there is a substantial difference in price: sometimes 15, 20 or more cents per kilo, which warrants investing in order to ensure the absence of seeds.
Better still: Marcos Gual, from the export company Burriana Bagú, says that “in our case, as specialists in clementines and mandarins, it is not just a difference in price, but a matter of definitively validating ourselves as producers and suppliers of fruit that is guaranteed to be seedless”.
With this idea in mind, some initiatives began by manually “covering” with netting. In Bagú they designed some supports to make the task easier, but the costs were high. It was a matter of automation, and so they started to consider different options.
At that moment Juan Antonio Sagarra, specialist in the manufacture and design of different agrarian equipment, from the Saflowers y Sadol firm in Fraga (Huesca), came on the scene. Juan Antonio had commercial and technical contacts with Bagú because he had supplied them with specific plant protection treatment quads for citrus fruits, like many citrus fruit and other fruit sector businessmen throughout Spain. The orange producing company Bollo, from Benifairó de la Valldigna, also purchased quads for treatments, and, like Bagú, asked whether he “had something or could design something for efficiently placing the netting over the rows of Nadorcott trees; and so we got into the factory and designed something suitable”.
Last year they successfully tried the hydraulic and articulated arm, designed in Fraga, on the Bollo farms, and the success was so resounding that news spread like wildfire among producers of the mandarin and the Huesca company had an influx of orders, because everybody wanted to cover their trees. The big producers purchased the machine, but in other cases there are service companies emerging that buy them and do the work for small and medium-sized cultivators, as occurs in other agrarian tasks. In addition, the manufacturer has already made improvements to last year’s arm, and other improvements are made on the fly.
As regards cost, Juan Antonio makes reference to what was generated last year: 5,500 euros per hectare, including the netting, the work for laying it and that of removing it. The additional cost represented 10 cents per kilo of fruit, but for a variety sold at 70, 80 or 80 cents, the difference between having seeds or not having them means everything.
In a farm in Vagú in Castellón we witnessed the evolution of the machine, able to cover two rows of trees at the same time, which also diminishes costs. There is no need for a large tractor, a simple one is sufficient. It’s also better if it doesn’t have a cabin so the driver can hear the instructions of those helping to lay the netting on either side. The netting comes from the roll connected to the back of the vehicle, which is lifted by the articulated arm, which then lays it over the trees. Workers hold it down and then fix it to the floor with stakes. The trees remain covered for six weeks, after which the netting is rolled off and saved for the next season. If a treatment was needed whilst the netting is in place, it can be done. The tractor and the spraying tank can pass between the rows of trees and the holes in the netting are large enough for the phytosanitary liquid to pass through.
Marcos Gual, from Bagú, is particularly satisfied “because this way we ensure that the pollinating insects cannot cross pollinate, without harming them, we just cover the trees to avoid it.”