Recording the Rate of Application
What should you write on records and notices?
Labels detail mixing rates – so many ml/L – but how is it best recorded?
Accurate records of the rate of application are critical for paperwork, information for customers and also durable notices for termite work. Over the years the manufacturers as well as some regulators and educators have changed their descriptors and requirements from percentages to weight or volume per weight or volume expressions. Some pest managers will remember Baygon 20 changing to Baygon 200 (in about 1986) – indicating a change of expression from 20% to the equivalent 200g/L. Cislin Residual Insecticide is commonly referred to as Cislin 10 – indicating it contains 10g/L deltamethrin.
Percentage refers to 1 in 100, g or mL / kg or L refers to 1 in 1,000. So 1% is the same as 10g/L. The difference is simply whether it is parts in a hundred or a thousand and therefore the placement of the decimal point. These days, the concentration of the product is expressed as g/kg or g/L on the label, so why add another possible point of confusion by converting to %.
In the past pest managers referring to a 1% concentration was open to two interpretations, especially with products containing 100g/L. Using use Biflex® Ultra as an example - it contains 100g/L bifenthrin. The concentration of Biflex in the emulsion is 1%, but the concentration of bifenthrin, the active ingredient is 0.1%. It may be diluted at 1L/100L – a 1% dilution. So what does Biflex 1% compared to bifenthrin 1% mean? Confused? That is why it is simpler to state the name of the product but also write g/L and the active ingredient.
Expressing rates as g/L etc, the rate of application is easier to calculate and not likely to be misinterpreted.
Concentration of emulsion = initial concentration (g/L) x dilution
Biflex ® = 100g/L (as on the label) x 1L / 100L
(assume 1L/100L dilution)
Biflex ® = 100g/L x 1 / 100 = 1g/L bifenthrin
Premise® 200g/L x 0.250L (=250mL) / 100L = 0.5g/L imidacloprid
Termidor® 100g/L x 0.600L (=600mL) / 100L = 0.6g/L fipronil
Cislin® 10g/L x 0.150L (=150mL) / 5L = 0.3g/L deltamethrin
(assume 150mL/5L dilution)
Ficam ® 800g/kg x 0.030kg (=30g) / 5L = 4.8g/L bendiocarb
NOTE: In these calculations one g is taken to be equivalent to one mL (and a kg = L).
The Queensland Pest Management Regulations 2003 state that the strength of active constituents shall be expressed as g/kg, g/L, mL/L etc.
Biflex is a Registered Trademark of FMC Corporation,Philadelphia, USA
Premise, Cislin and Ficam are Registered Trademarks of Bayer A.G. Leverkusen, Germany
Termidor is a Registered Trademark of BASF