The absorption and movement of ³²P-labelled systemic insecticides in the grape vine (Vitis vinifera L.)

Abstract

Three systemic insecticides, schradan, dimefox, and demeton-S, containing ³²P , were applied by different methods at different times to study their behaviour in grape vines, particularly their accumulation in roots. Foliage sprays, "capsule" treatment, and banding of the trunk (with various supplementary treatments such as cincturing, abrasion, and twig removal) gave low levels of insecticide in the roots; some of these treatments gave high levels in the leaves. Watering in November and February, and shoot injection in April, resulted in concentrations of 17 mg schradan per kg in roots 15 days after treatment. Schradan accumulated in vines at slower rates, decomposed less, and was less affected by time of treatment than has been reported in other plant species. Dimefox was absorbed in amounts about equal to schradan but it decomposed rapidly, so that low levels of insecticide were found in the roots. Dimefox was phytotoxic when applied in a trunk band. Demeton-S levels were low in roots owing to its ready transport to leaves. The evidence suggests that it does not move easily in phloem.