Publication 360, Fruit Production Recommendations: Handling and Mixing Pesticides


Publication 360, Fruit Production Recommendations > Chapter 10, Pesticide Application > Handling and Mixing Pesticides
Excerpt from Publication 360, Fruit Production Recommendations 2010-11,
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Cover of Publication360, Fruit Production RecommendationsTable of Contents

  1. Formulations
  2. Soluble packaging
  3. Compatibility of spray materials
  4. Other Information on Pesticide Application
  5. Related Links

Handling and Mixing Pesticides

Formulations

Dry pesticide formulations include granules, soluble powders and wettable powders.

  • Wettable powders will not dissolve; when mixed with water, they form a suspension that requires constant agitation. Unless the label claims otherwise, premix wettable powders with water and add the slurry to the spray tank.
  • Granules are ready to be added directly to water.
  • Soluble powders can be dissolved in water.
Liquid pesticide formulations mix in water to form a solution. Some pesticides may be oil-based and form an emulsion that requires agitation.


Soluble packaging

Choose soluble packages that dissolve in the carrier water to reduce container disposal issues. Water-soluble packaging is used for dry flowable and wettable powder formulations of pesticides and is available under names such as Clean Pak, Solupak, and Toss-N-Go. In most cases, the water-soluble packaging material is PVA (poly vinyl alcohol). This material dissolves completely when added to the water in the sprayer tank according to instructions.

  • Read all labels and instructions carefully. For more details contact the vendor.
  • Keep soluble pouches dry until added to the spray tank.
  • Do not handle pouches with wet hands or wet gloves.
  • Do not remove pouches from the outer package until just before use.
  • Always reseal the outer package to protect the remaining pouches from moisture.

Mixing soluble pouches:

  • Consult product labels for specific mixing instructions for each product.
  • Half-fill the spray tank with water and have the agitator running - then add the water-soluble pouches to the tank.
  • Most pouches dissolve completely within 5 minutes, depending on the water temperature and the degree of agitation.
  • As the tank continues to fill, add any other compatible pesticides.

Do not add:

  • A pesticide that is incompatible with the PVA packaging material. The PVA material is not soluble with oils (e.g. Superior Oil).
  • Any material containing boron (e.g. Solubor), chelated micronutrients or water-soluble fertilizers. This combination is likely to cause a sticky, insoluble substance in the tank.

Compatibility of spray materials

For information on compatibility of spray materials, always check the product label. Compatibility refers to the physical or chemical compatibility of two products in a solution. Physical incompatibility can result in a physical change in the solution. Components of the combined product may plug nozzles or become solidified or gummy in the tank.

Chemical incompatibility can result in a chemical change in the solution. This can lead to reduced efficacy, or can cause plant injury when sprayed on the crop. The results of a chemical incompatibility may not be evident until after the spray is applied.

In general:

  • Compatibility of two products varies with the formulation of those products. For example, two products may be compatible as wettable powder (WP) formulations, but the same active ingredient may be incompatible as emulsifiable concentrate (EC) formulations.
  • Compatibility generally refers to two-way mixtures. Adding a third product to a tank-mix, even if all are compatible with each other in two-way combinations, may result in further incompatibility.
  • Compatibility of some materials may depend on the solvents and emulsifiers the manufacturer uses. Emulsifiable concentrates are more likely to cause compatibility problems than wettable powders. If wettable powders are mixed with emulsifiable concentrates, incompatibilities may result.

Specifically:

  • When mixing Captan or Maestro with EC formulations of pyrethroids, add Captan or Maestro first. Apply immediately with constant agitation.
  • Do not mix pesticides with lime sulphur or streptomycin.
  • Do not use oil sprays within 14 days of Captan or Maestro. This applies also to the oil used with Agri-Mek.
  • Water soluble, polyvinyl alcohol packaging (PVA) material is not compatible with Superior Oil, or EC formulations containing mineral or vegetable oil products.
  • Water-soluble packaging is not compatible with boron, some chelated micronutrients and water-soluble fertilizers. Rinse the spray tank carefully after applying these nutrients, before using products in water-soluble packages.

For more information on compatibility, contact the product manufacturer or dealer.

Related Links

 


For more information:
Toll Free: 1-877-424-1300
Local: (519) 826-4047
E-mail: ag.info.omafra@ontario.ca
Author: OMAFRA Staff
Creation Date: 14 June 2006
Last Reviewed: 16 July 2010