By: Raúl Osorio, Director of Peulla Consulting and Services.
The first written records of pest control are found in the Egyptian Book of the Dead and the Old Testament, referring to the use of sulfur compounds by the Sumerians to control insects and mites. The Chinese, on the other hand, used botanical insecticides and compounds based on mercury and arsenic about 1200 years before Christ. (Agrochemical Application Technology, first edition 2010 Magdalena, J Carlos et al.).
The contribution from the equipment for the application of liquid products was made by CV Riley when he invented the turbulence nozzle in 1888. The Second World War and the appearance of new agrochemicals led to a boom in crop protection. This revolution was accompanied by a new generation of spraying equipment that made the task of pest control more agile and economical. In fruit growing, applications were made by hose, with high volumes up to "dropping point”.
In the late 1950s, there was a significant technological advance in fruit growing with the use of air as a transport element. Ponds evolved from wood to plastic and ceramic ponds resistant to abrasion. Today, we have the use of electronics and telecommunications and ofsoftware which provide significant elements to improve the effectiveness and efficiency of the application of agrochemicals (Agrochemical Application Technology, first edition 2010 Magdalena, J Carlos et al).
Effective pest control will always depend on 3 factors that are closely related:
1) Time of application: from the point of view of pest susceptibility.
2)Suitable product for the control and
3)Application technology.
The responsibility, expressed in proportion to each of the factors mentioned, is described in the attached figure:
The first invitation has 3 items:
1) Choose a good agrochemical product (active ingredient and effective formulation), with sufficient support, a reasonable cost for its objective, ideally with low environmental impact and always consider its dosage range.
2) Use agrochemical products in a timely manner depending on the development stages of our crop, the susceptibility states of pests and diseases and, depending on these, use the correct doses within their range.
3) Finally, use application equipment that is always well maintained, clean and optimally calibrated to develop applications in a wide range of water volumes or “application rate”.
If we consider that the cost of foliar programs (nutrition and health) amounts to between US$ 3000 to 4000 / ha, that the associated cost of each application is US$ 25 / ha (MO – Machinery), and we have between 20 to 25 applications per season; this cost is US$ 600 / ha, additional.
In total we are using between US$ 3,600 to 4,600/ha/season; it is certainly a large annual investment and we must use it very effectively and efficiently.
One of the key aspects in the fight against pests and diseases is to always obtain the largest deposit of the active ingredients contained in the formulations, always avoiding losses, drift or runoff into the soil or structures where they will have no effect.
The proposals we have developed in previous articles (https://smartcherry.cl/planificacion-tareas/calibracion-y-mantencion-de-equipos-de-aplicacion/consideraciones-para-las-aplicaciones-de-precosecha-de-cerezos/) we can summarize them in the following recommendation:
1) Leaf fall and winter break: between 500 and 750 L / ha
2)Flowering to beginning of setting: 750 to 1000 L / ha
3) Pre-harvest setting: 1000 to 1200 L / ha
4)Exceptions: wood pest problems (e.g. St. Joseph scale), 1500 to 2000 L/ha.
Along with the volume of water needed to transport the applications, we need an air flow rate to carry the droplets to the different structures of the crop. The speed of advance must be defined in order to deliver the necessary amount of air to replace the air inside the tree with the new air loaded with the agrochemical(s) (Agrochemical Application Technology, First Edition 2010 Chapter 10 Homer, Ian et al).
This volume of air required at each stage of cultivation can vary from 15,000 to 22,500 m3 of air/ha, if we consider an “average” orchard of 3 meters high, with a canopy width of 3 meters and a planting distance of 4 meters between rows. Continuing with the same example and having available an atomizing equipment that gives us an average air speed of 18 meters / sec (65 km/hour) at the exit of the “air channels”, we would have available 40,000 m3 of air / hour.
If we need to “move” the air from the crop to load it with agrochemicals, in the example we can drive at speeds of between 4.5 and 6.5 km/hour. We will use an application time/ha that will vary between 23 and 34 minutes/ha. If we have a “plant population”/ha of 833, we can assist each plant between 1.7 and 2.4 sec/tree (Table 1).
The range of forward speeds will depend on the availability of tractor-spraying equipment, distances between rows, application objective, and mainly on the qualities of our terrain. Always taking into account the minimum use of product with the maximum impact of control on pests and diseases and with the minimum impact on the environment for operators and consumers.
In summary, our invitation to each actor in our production system is to achieve Optimal Efficiency in the use of each tool used (agrochemicals), obtaining the maximum profitability of each of them by being Efficient in their use: Products, Qualified Labor, Machinery, Water, Energy and Time.
In order to develop effective and efficient application management plans, we must have previously diagnosed equipment in all its components, repaired and replaced its critical elements, perform annual and periodic maintenance, permanent cleaning and have highly trained personnel to develop the applications that will translate into the success of our crop at harvest with the least impact on the environment and people.
