Coverage

The percentage share of target surface that is covered with the active agent is chiefly dependent on a number of technical, chemical and biotic factors. If the recommended application rates are adhered to, coverage should amount to at least 10 to 15%.

Contact agents require uniform coverage, while (semi-)systemic agents must instead reach the part of the plant where the upward distribution process tends to begin.
 
The user's options for increasing the degree of target-surface coverage are limited:

• By technical means: either the spray pressure can be raised or a nozzle producing finer droplets can be used to improve atomization.
• By chemical means: the surface tension can be reduced, somewhat smaller droplets generated, secondary atomization enhanced, and/or a lower viscosity employed.
• By biotic means: the nature of the target surface (coat of wax or hair, phyllotaxy/leaf arrangement), i.e., the hairier the leaf and the wider the angle of impingement, the better the coverage.

You will find more information in our brochure

Coverage and biological-efficiency criteria for agricultural spray nozzles [PDF]