Surface tension and suspensibility of spray liquids of fungicides, insecticides and non-pesticide substances depending on water quality

Abstract

The aim of this work was to determine the surface tension and suspensibility of spray liquids of fungicides (Quadris and Dithane M-70), insecticides (Actara WG-25 and Cipkord EC-20) and two and/or three component mixtures with non-pesticide substances (complex fertilizer - Mortonjic plus and adjuvant - Sillwet L-77), depending on water quality. For this work the following waters were used: well water from Becej (slightly alkaline, slightly soft), well water from Adice (slightly alkaline, very hard), tap water from Novi Sad (neutral, slightly hard) and surface water from Sava and Karas rivers (slightly alkaline, slightly hard). Surface tension of fungicide and insecticide spray liquids and their mixtures in mentioned waters was determined using tensiometer and suspensibility according to a standard method (CIPAC MT 15). The surface tension of all tested waters was high. However, the reduction of surface tension by 50 % (or more in water from Sava river) compared to the control waters, was achieved by adding the adjuvant (Sillwet L-77) and insecticide formulated as emulsifiable concentrate (Cipkord EC-20). Surface tension was slightly decreased in a single component spray liquids of fungicides and the complex fertilizer, as well as in mixtures that did not contain adjuvant and/or Cipkord EC-20, regardless on water quality. Suspensibility of all spray liquids, regardless on tested water was above the lower limit (60 %). In general, the suspensibility all mixtures containing Dithane M-70 was reduced compared to Dithane M-70 spray liquid, in all tested waters. The most pronounced decrease in suspensibility, below 70 %, was registered in the case of spray liquids with tap water, compared to others (99.8 %).