As stated in other publications, the application of pesticides and foliar nutrition is one of the most important practices in global horticultural production. In some cases, it represents over 50% of the machinery used in a fruit orchard during a season (Source: Jorge Riquelme S. and Patricio Abarca R., INIA Dissemination Leaflet No. 1).
It is a general consensus among the main advisors and producers of cherries that “the next growing and production season of the crop begins in post-harvest.” These serious wood fungi are a common problem affecting cherry trees in producing regions. There are four main pathogens found in cherry orchards: Cytospora spp., Calosphaeria pulchella, Eutypa lata, and Chondrostereum purpureum. Here we explain how to distinguish each one (Wood Fungi in Cherry Trees: How to Identify, Prevent, and Manage These Pathogens, Smartchery, June 12, 2024).
What phytosanitary solutions do we have for control?
The available phytosanitary solutions for these objectives are diverse, including: strobilurins (pyraclostrobin), benzimidazoles (benomyl), thiophanates (methyl thiophanate), triazoles (tebuconazole), and microorganisms (Trichoderma spp.), among others.
Knowing the level of effectiveness (labels) we can achieve with one or another available tool for controlling these serious wood diseases, we must consider how to effectively reach the structures of our crop.
What doses and instructions should we use?
Carefully read the usage instructions on each label to use the appropriate dose. Pay attention to the mixing instructions, compatibility or incompatibility with other solutions, phytotoxicity, re-entry time, and precautions. In the case of applying biological products, factors such as temperature, relative humidity, UV light, and applied structures like conidia, mycelium, or chlamydospores should be considered.
What volume of water do we use to apply solutions for wood diseases?
The volume of water required for adequate coverage in the crop can be determined by assessing the size of the crop in each situation considering: crop age, planting density, crop height, and the training and conduction system of the crop primarily.
The recommended range of water volume for a crop at a productive age (not formative) and considering the various mentioned situations will fluctuate between 1000 and 1500 L of water per hectare. We must ensure that we cover the fruiting bodies of wood fungi for more effective control.
How do we ensure that a large proportion of our application is deposited on the target?
For applications in general, we must keep in mind that the droplets containing the solutions should be projected from the pneumatic atomizer by means of wind; therefore, we should perform applications with the necessary amount of air (correctly replacing the air inside the tree with the sprayed agrochemical, Ian Homer et al., Technology of Agrochemical Application, 2010, first edition).
Agronomist Guillermo Lorca Beltrรกn, professor of Agricultural Mechanization at the Faculty of Agronomy of PUC in Chile, details how to calculate the necessary air quantity for effective applications (Mundoagro Magazine, June 2016, ACCURACY WITHOUT RUSH How to Select the Speed and Pressure of Work in Agricultural Sprayers to Achieve Maximum Efficiency and Effectiveness).
In summary, the equipment used in most cherry orchards can displace a sufficient amount of air to achieve the goal of transporting the applications (from 40,000 to 60,000 mยณ of air/hour).
We must also consider a minimum exposure time of the plants to the applications with the pneumatic atomizers, to ensure that the displaced droplets can settle on the target. The slower the application, the greater the deposit of the applications.
To provide a post-harvest application recommendation aimed at wood diseases that is effective, we suggest that application speeds fluctuate between 5 and 6 km/hour to ensure the exposure time of plants to applications is between 1.5 to 2 seconds per plant (field case evaluations).
Maintenance of Agricultural Sprayer Equipment
We must always develop a rigorous inspection protocol for the machinery intended for applications and carry out preventive maintenance on each of the available equipment (sprayers and tractors). Once maintenance is performed, we must have precise calibration guidelines suitable for each situation in the orchards.
In previous articles, we have emphasized the importance of each component of a sprayer and annual preventive maintenance as well as the periodic control, in addition to the tractors used for this important work.
By Raรบl Osorio, agronomist and Director of Peulla.
Image courtesy of Mauricio Rubilar, agronomist.