According to official data from the Office of Agricultural Studies and Policies, ODEPA, the surface area of cherry trees in Chile currently reaches 39,645 hectares, however, for many people linked to the sector, the figure would actually be closer to 50 thousand.
The expansion of the cultivation of this fruit species has been such that today it is present from Ovalle in the north to Chile Chico in the south of our country. Fields that were previously used for table grapes, vineyards, apple trees, among others, have been replaced; this situation has caused cherry orchards to be affected by pests that were common in other crops or fruit trees.
The Agricultural Engineer and Director of the Syngenta MIPNET Monitoring Network, Cristian Arancibia, highlighted the importance of proper pest management, considering that this is essential, especially for export fruit: “There was always the stigma that cherry trees were pest-free, and in general and historically, producers did little phytosanitary work, but as the planted surface increases due to the opening of markets, pests and restrictions appear that make it necessary to implement control programs. When a market opens, a protocol is established with that destination country. This agreement certifies the health of what is exported; it is not just about arriving and selling. For example, China, there is a protocol behind it, a job that must be done to be able to reach that market with fruit without pests that are present in Chile, but not present in China,” explained Cristian Arancibia.
But what are the main pests that affect cherry trees and how to manage them in post-harvest?: “We are in the long post-harvest of cherry trees and we have three groups of pest species that we can control or manage in this period; scales, phytophagous mites, there are several species that we must control to prevent leaf deterioration, etc., and even Drosophilla suzukii,” Arancibia explained.
In the case of scales, the professional referred to two species that could affect a cherry tree; the classic St. Joseph scale (Diaspidiotus perniciosus) and the Coma Scale (Lepidosaphes ulmi), which is much more secondary in most deciduous fruit trees, but in the case of cherries it is a quarantine species for China and the main cause of rejection in cherries for export to that country.
When can they be controlled?
There are three control periods depending on the species. «Scale control in spring is complicated because we have little time and we must comply with the lack of phytosanitary products and try to achieve the greatest effectiveness; we can control the Coma scale during the first half of October. However, the early cherry harvest, from the end of October onwards, coincides, to a large extent, with one of the migration cycles of the St. Joseph scale, so we miss one of the best control opportunities. Therefore, we must implement management programs at the end of winter, that is, before budding, where we must differentiate these species, since it is very effective for the St. Joseph scale, but not very effective for the Coma scale, because their cycles do not coincide. Post-harvest is different, since we have a lot of time to carry out efficient management, but it depends on the biological cycle of each species, because it must be applied when the pest is most susceptible to control; For example, if we are harvesting an orchard in November where we find scale, either by prospecting in the field or by detection in the packing plant, a control must be done coinciding with the summer migration in post-harvest, just in January or February, depending on whether it is Coma scale or San Jose scale, respectively; even, San Jose scale can be controlled in a third biological cycle during April depending on the weather conditions. Also, it is very common to detect Phytophagous Mites or even little pig white, in which cases the phytosanitary management will depend on the biological cycle of each pest species and its control thresholds," explained the Director of the Syngenta Monitoring Network, Cristian Arancibia.
The well-known spider mites or Phytophagous Mites are another group of pests that affect cherry trees and can seriously damage the leaves of the trees, which are essential for different processes in the orchard, such as the accumulation of reserves, among others.
“There are different species, European Red Spider (Panonychus ulmi), Two-spotted Spider (Tetranychus urticae) and the grass spider or pasture spider (T. desertorum); these species cause direct damage to the leaves and, therefore, can also affect the accumulation of reserves of the dart for the next season, so if there is a problem of “summer scratches”, with a very high population of Phytophagous Mites, regardless of the species, you are going to have reserve problems and next season we may have poorer flowering, weaker flowers or smaller-sized fruit. It can affect the productive potential of an orchard, because if you do not manage it you can have defoliation in the middle of January,” Arancibia specified.
But without a doubt one of the most complex plagues of recent years is Drosophila suzukii; it not only affects cherry trees, but also other fruit trees, and even wild species, which makes its control even more complex.
“When one speaks of a species, which is as prolific and polyphagous as Drosophila suzukii, It attacks a large group of fruit trees, which is developing in wild species, in the blackberry bush, which you have in the field and which can have up to 15 generations in a year, there is an urgent need to establish a preventive management program in pre-harvest with highly effective agrochemicals, since not any mode of action works satisfactorily; even the type of formulation of the product, adding to a cultural management and strict monitoring, is fundamental, since the possibility of having failures and generating economic losses is very high, more than with other pests, which we are used to managing. It is not a quarantine pest, in 2008 it was detected in Europe for the first time. Drosophila suzuki and in four years it covered the entire continent. In North America it was also detected in California in 2008 and in a short time it spread from Mexico to Canada and between the west and east coasts. In Chile it was detected for the first time in 2017 and this last season it was declared a pest present from the O'Higgins region to the south. When the orchard is harvested, fruit remains on the trees and also falls to the ground. This fruit can be a source of propagation of Drosophila suzukii in the field and must be monitored, since within the cultural measures for the management of this pest species, the fruit that remains on the trees or that falls to the ground must be removed or at least treated with agrochemicals in post-harvest," warned Cristian.
Arancibia.
For the Agricultural Engineer and Director of the Syngenta MIPNET Monitoring Network, it is very important to have adequate equipment in good condition to carry out good control and effective management of pests; this would be one of the bases for the success of product applications: “Within our service management area, as a Monitoring Network, there is the calibration of equipment. In more than 12 years, in general, when a diagnosis of equipment is made, about 90 percent have some fault and a little more than half have problems with the nozzles, without speaking of other things such as speeds and volumes applied per hectare as examples. There is still a lot to develop to achieve a good application, going through good diagnoses and consequently good calibrations of equipment, with which you ensure that you can reach the objective, because the application itself is placing where you want the product with which you are going to control the pest or disease; The objective of the application is to reach where you want to place the agrochemical you are applying, so if you have poorly calibrated equipment you will not reach it and you will have problems."
Finally, the specialist warned that pest management should not only focus on the fruit trees inside the orchard, but also on the perimeter of the field, the living fences, what surrounds the orchard, for example, bushes, native forest, in the neighboring crop, as they can be sources of increased pest population that could eventually affect a cherry orchard, such as the most recent, Drosophila suzukii or spotted-wing fly.
