By: Raúl Osorio, Director Peulla Consultancy and Services.
The first written records on plague control can be found in the Egyptian Book of the Dead and the Old Testament, which reference sulfurous compounds used by Sumerians to control for insects and mites. Meanwhile, the Chinese used botanical insecticides and a mercury and arsenic-based compound about 1200 B.C. (Tecnología de aplicación de agroquímicos [Agrochemical Application Technology], first edition 2010 Magdalena, J Carlos et al).
An important equipment-oriented contribution for liquid product application was made by C. V. Riley when he invented the cyclone nozzle in the year 1888. World War II and the introduction of new agrochemicals led to a peak in crop protection. This revolution was accompanied by a new generation of spraying equipment that made for a more agile and economically sound pest control. In fruit growing, applications were performed with hoses transporting high volumes until the “dripping point” was reached.
By the late 1950s, there was a transcendent technological advance in fruit growing in the form of applying air as a transporting element. Containers evolved from wood to plastic and abrasion-resistant ceramics. We currently have at our disposal electronics, telecommunications and software that provide us with significant elements for the improvement of efficacy and efficiency when applying agrochemicals (Tecnología de aplicación de agroquímicos [Agrochemical Application Technology], first edition 2010 Magdalena, J Carlos et al).
Effective pest control will always depend on 3 closely related factors:
1)Timely application moment: from the point of view of plague susceptibility.
2)Product that is proper for control and
3)Application technology.
Responsibility, expressed in proportion for each of the aforementioned factors, is described in the attached figure:
Figure 1. Responsibility of different factors in effective application control.
The first invitation has 3 items:
1) Choosing a good agrochemical product (in terms of its active ingredient and effective formula,) with sufficient support, a reasonable cost given its objective, ideally a low environmental impact, and the constant consideration of its dosage range.
2) Opportunely using agrochemical products depending on our crop’s development states, on the pests’ and diseases’ susceptibility states, and, depending on the aforementioned, using the correct dosage in their range.
3) Finally, using application equipment that is always in perfect condition and well maintained, clean and optimally calibrated for the development of applications in a wide range of water volumes or “application rate.”
If we consider that the cost of foliar programs (nutrition and health) add up to somewhere between USD$ 3,000 and $4,000 per hectare, and that the associated cost for each application is USD$ 25 per hectare (M.O. – Machinery) considering between 20 and 25 applications per season; this cost represents an additional USD$ 600 per hectare.
We are utilizing, in total, between USD$ 3,600 and $4,600 per acre per season; this is undoubtedly a large annual investment that we need to use effectively and efficiently.
One of the key aspects in combating pests and diseases is always obtaining the greatest possible deposit of active matter from the products’ formulas, avoiding losses, drift or runoff of the product into the soil or structures where there will be no effect whatsoever.
The proposals we have developed in prior articles (https://www.smartcherry.cl/planificacion-tareas/calibracion-y-mantencion-de-equipos-de-aplicacion/consideraciones-para-las-aplicaciones-de-precosecha-de-cerezos/) can be summarized in the following recommendation:
1)Leaf drop and winter recess: between 500 and 750 L / ha
2)Blooming to initial setting: 750 to 1000 L / ha
3)Setting to Preharvest: 1000 to 1200 L / ha
4)Exceptions: problems with wood plagues (for example: “Escama de San José”), 500 to 2000 L / ha.
Along with the water volume needed to transport the applications, we need an air stream that will transport droplets to the different structures in the crop. Advancement speed must be defined in order to deliver the amount of air necessary for the replacement of the plant’s interior air with the new air, which will be loaded with the agrochemical or agrochemicals (Tecnología de aplicación de agroquímicos [Agrochemical Application Technology], first edition 2010 Chapter 10 Homer, Ian et al).
This necessary air volume at each cultivation stage can vary from 15,000 to 22,500 m3 of air / ha, if we consider an “average” orchard that is 3 meters tall, with a 3-meter crown spread and a planting distance of 4 meters between rows. Following the same example, and having at our disposal a piece of atomizing equipment that will deliver a mean air velocity of 18 meters / sec (65 km/hr) through the “air channel” vent, we would have, available, 40,000 m3 of air / hour.
Chart 1. Displaced air volume per hectare for “conventional” atomizing equipment
If we need to “displace” the crop air in order to charge it with agrochemical products, in the example we could reach speeds of 4.5 to 6.5 km/hour. We will use an application / hectare time that will vary between 23 and 34 minutes / ha. If we have a “plant population” / ha of 833, we can tend to each plant between 1.7 and 2.4 sec / tree (Chart 1.)
The advancement speed range will depend mostly on the availability of tractor – atomizer equipment, distance between rows, and application goal, aside from our terrain’s qualities. Always considering minimal use of product with maximal control impact on pests and diseases and minimal impact on the environment, on operators and on consumers.
In summary, our invitation to each player in our productive system is that we reach Optimal Efficacy in using each available tool (agrochemicals), obtaining maximal profitability from each of them and being Efficient in the use of: Products, Qualified Workforce, Water, Energy and Time.
In order to properly develop management plans for effective and efficient applications we need to have equipment that has had all of its components previously diagnosed, with their critical elements repaired and replaced; perform annual and periodical maintenance, allow for permanent cleaning, and ensure the availability of highly capable personnel to perform the applications that will in turn translate into successful crops and harvests with the least amount of impact on the environment and human beings.
