Optimisation of chemical application to improve pome fruit disease and pest management

Summary for 2012

• Deposition quantity was affected significantly by the applicator type and delivery
• Deposition quantity varied according to the location of the fruit, as well as the leaves, within the tree canopy.
• Deposition quantity was not affected significantly by the ground
• Standard energy delivery at 26,600 m³/h generally resulted in higher spray deposition using the Atasa (+) Turret applicator system, compared to delivery at 45,600 m³/h (high energy).
• Spray deposition was higher on fruit and leaves where a turret was added to the Atasa
• Deposition quantity levels were generally higher on fruit and leaves using the Atasa applicator, compared to the Cima, both with a turret added to the system. It though needs to be noted that adaptations have been made for the 2012 trials, to improve deposition with the Atasa system.
• Deposition quantity was higher for most applicator types, especially the Atasa (+)Turret, on top fruit and leaves, as well as outer fruit and leaves, compared to the same two target sites at the bottom and inner position of the tree canopy.
• Differences between top and bottom and between inner and outer target surfaces were higher for standard energy delivery compared to high energy, as well as the Atasa (+)Turret compared to the Cima (+)Turret. This finding corresponds to the quantity delivered to the different target

Summary for 2011

• Deposition quantity, efficiency and uniformity of spray applications of leaves and fruit of Pink Lady apples were affected by applicator type, use of a turret, energy delivery level and droplet size, all relative to each other, with specific advantageous attributes on leaves and fruit.
• Deposition quantity and efficiency was higher on outer leaves, at the bottom of the
• Deposition quantity and efficiency improved with a Turret affixed to the Atasa
• Quantity and efficiency generally better with use of the Cima applicator (+)Turret, than the Atasa with or without Turret.
• Quantity and efficiency not affected by droplet
• Deposition quantity and efficiency only affected by energy delivery level with use of the Atasa (+)Turret spray system, with higher deposition quantity achieved with the Std. energy application than Reduced energy.

Summary for 2010

• Deposition quantity and quality, as well as spray uniformity and efficiency on leaves and fruit of Pink Lady apples sprayed in the orchard, were significantly affected by applicator type, spray volume, tree height and canopy depth.
• Deposition quantity was higher at the top or centre of the tree, across
• The Atasa (+) turret generally deposited more product on outer fruit and leaves than the Cima (+) turret.
• The Atasa (-) turret showed a tendency to deposit more product on the outer leaves and fruit in the centre of the tree, compared to the Atasa (+) turret.
• Generally, results for deposition quality were the inverse of deposition
• Deposition quality was better with the Cima (+) turret at the top and centre on outer leaves and fruit than both the Atasa applicators, most likely since the latter applicators deposited more product at these zones.
• High volume spraying deposited more product onto fruit and leaves, especially in the outer position on the tree.
• The quantity of deposition on inner leaves was not affected by the applicator
• The use of a turret along with the applicator could generally ensure deposition of more product on inner leaves and fruit.
• Low volume spraying generally resulted in better deposition quality than high volume at the top and centre of the tree.
• Spray efficiency was better for the Cima (+) turret at low volume application, while better for the Atasa (+) turret at high volume.
• Spray efficiency was higher at the top and centre of the tree than at the bottom for high volume
• Spray uniformity, a function of deposition quantity and the coefficient of variation, was generally better for high than low volume application.
• Spray uniformity was least affected by volume variation with use of the Cima

Summary across seasons (2010, 2011 & 2012)

• The study across the years showed that spray deposition of a chemical is dependent on various parameters, such as applicator type, spray volume, energy delivery and droplet size, with further differences likely to occur depending on the location of the target surface, not to mention the effect of timing, whether conditions, fruit kind, trellis systems and horticulture practices, etc.
• The findings imply that efficacy of sprays could vary depending on the various spray factors outlined above.
• The importance of spray management and understanding the effect of certain parameters may have on spray deposition and hence, are clearly shown across seasons in different trials.