Publication 360, Fruit Production Recommendations: Sprayer Calibration and Nozzle Maintenance

Table of Contents

1. Introduction
2. Calculating actual driving speed
3. Nozzle maintenance
4. Other Information on Pesticide Application
   • Handling and Mixing Pesticides
   • Filling and Agitation
   • Calculating Water Volume and Pesticide Rates
   • Sprayer Calibration and Nozzle Maintenance
   • Calculating Output
   • New Developments in Spraying Technology
   • Other Resources in Application Technology
5. Related Links

Sprayer Calibration and Nozzle Maintenance

Introduction

Calibration is a test measurement of the performance of the application equipment under typical operating conditions. This generally means nozzle orientation and output, which change over the spraying season. Calibration is recommended twice per season - at the beginning and about mid-way through. A properly calibrated sprayer can prevent many of the following problems:

• Pest Escapes: Uneven application or improper dosage can result in poor pest control.
• Pesticide Residues: Inconsistent application rates may leave excessive residue levels on fruit.
• Crop Damage: Uneven nozzle outputs can deposit too much product on sensitive crops.
• Poor Returns: Expensive re-application of pesticides together with losses in yield and quality can lower expected returns on high value crops.
• Drift: Improperly oriented nozzles and inaccurate gauges can contribute to drift.
  

Calculating actual driving speed

Speedometers can become inaccurate over time or because of wheel slippage during spraying. An important part of sprayer calibration is checking your driving speed by timing how long it takes to drive over a measured distance under true field conditions.

• Use a tape measure to place two stakes 50 m (164 ft) apart in the field.
• Fill the sprayer half full of water.
• Select the throttle and gear settings you plan to use when spraying.
• Drive the distance between the stakes three times, timing each pass in seconds. Each time, make sure the tractor is at the desired spraying speed as you pass the first stake. Keep driving at this speed until you pass the second stake. Run the course in both directions and do not drive in the same tracks.
• Take the average time of three passes and use the formula below:

  (Test distance (A)÷ Average travel time in seconds (B)) × Constant (C) = Driving speed in km/hr ((A÷B)×C)
  eg. 50 metres ÷ 36.25 seconds x 3.6 = 5.0 km/hr

A modern alternative is to use a hand-held GPS receiver to determine accurate forward speed in specific gears at known RPMs. This tool is also handy for measuring row length and block areas.

Nozzle maintenance

Nozzle wear or tip damage has a direct impact on product effectiveness and cost. The rate of tip wear depends on spray pressure, product sprayed, and the material of which the nozzle is made. Do not use nozzles made of different materials on the same boom. Upgrading to a harder, more durable tip can reduce maintenance costs, but even ceramic tips will not last forever. The most common tip materials, listed from softest to hardest, are:

• brass
• stainless steel
• plastics
• hardened stainless steel
• ceramic
  

Related Links

• Pesticide Application and Safety
• How Weather Conditions Affect Spray Applications Order No. 09-037w
• Six Elements of Effective Spraying in Orchards and Vineyards Order No. 09-039
• Adjusting, Maintaining and Cleaning Airblast Sprayers Order No. 10-069
• The Hidden Cost of Damaged Nozzles
• OMAFRA Sprayer Calibration Calculator
• Grower Pesticide Safety Course Manual
• Pesticide Companies and Agents
• Search the PMRA website
• Ontario Minor Use Program
• OMAFRA Publication 75: Guide To Weed Control: Tree Fruit