Gideon van Zyl, Paul Fourie, Tian Schutte, Tim Grout (CRI) and Johan van Zyl (Nexusag)
CRI Cutting Edge, Research News from Citrus Research International
Fungicides and pesticides are only as effective as their application. The main objective of spray application is the optimal dose transfer of the well agitated tank mix, which includes one or more active ingredients, from the sprayer to the tree, whilst keeping off-target losses from run-off and drift at a minimum.
For effective disease or pest control, deposition of a uniform distribution of the required quantity of active ingredient(s) is required on the intended targets, be it outsidecover sprays on the outer canopy, medium-cover sprays on all fruit and medium-sized branches to full-cover sprays on all parts of the tree above the ground. Whilst high spray volumes (> 10,000 L/ha) generally meet the requirements for medium- to full-cover sprays, higher volume sprays are less efficient in terms of time and cost effectiveness. Reduced volume applications offer the potential for significant cost and time savings, but these applications require much more diligent attention to spray technique, sprayer calibration and maintenance.
The attached quick guide includes a spray checklist to be followed before and during the spray season, calibration guidelines as well as basic implementation factors. This guide should be consulted whenever citrus orchards are sprayed.
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For chemical store guides and mixing procedure tables contact Gideon van Zyl gideonvzyl@sun.ac.za