Abstract
Pysicai experiments with the mixtures of pesticides were conducted on the relations between the surface tension of fungicidal suspension and the deposition of the fungicides on the citrus leaves. The results of these experiments are summarized as follows;
1. High correlation was recognized between the surface tensions of various kinds of fungicides and its deposition upon citrus leaves. This correlations are shown by following formula.
y=0.2313x-7.5743
(y: weight of deposit on the 500cm2 citrus leaves in gram., x: surface tension of fungicidal suspensions in dyne/cm2)
2. When fungicides were mixed with insecticides or spreader the surface tension of the fungicidal suspensions became almost equal to that of pesticides or spreaders.
3. The relation between surface tension of insecticidal suspensions or spreader and the deposition of fungicides upon leaves are shown by the following formula;
y=0.236x-7.541
4. In case of the mixtures of Dithane M-45 with insecticides their surface tension (72.5dyne/cm2) went down to that of other suspensions or emulsions mixed, and consequently the fungicidal deposit decreased on citrus leaves. These relations are indicated as the following formula;
y=0.2287x-7.02
5. The spraying of fungicides mixed with insecticides or spreaders reduced the fungicidal deposit on citrus leaves compared with the fungicide alone. The quantity of fungicidal deposit is the more variable when the surface tension of fungicides the higher or that of the additives the lower.
