A Guide to Grapevine Abnormalities in South Africa - P.G. GOUSSARD

PART 9

HERBICIDE PHYTOTOXICITY 9

D espite research-based and strict scientifically based guidelines according to which chemical herbicide strategies should be approached and applied, the incidence of abnormal phenomena – as associated with the injudicious application/utilisation of chemicals – is by no means unknown, in which case they occur on a periodic basis in affected vines. Due to the fact that significant economic damage/losses may be suffered in such cases, it is of cardinal importance that planning procedures regarding the implimentation of herbicide programmes must at all times be executed in close consultation/co-operation with experts. Of course the abovementioned is also applicable in situations where existing programmes will be subject to adjustment/amendment – in which case successful weed control may be promoted continually in the most environmentally friendly ways. Overall it is further of great importance to continually keep up with identification procedures regarding herbicide- induced abnormality phenomena in affected vines. As current programmes are based chiefly on the application of mixtures – in contrast with the past when products were mostly applied singly – concrete/positive idendification(s) have become significantly more complicated. In addition, based not only on mutual differences, but also where confusion with other and even totally differing causes may occur, obtaining expert advice is strongly advised, to bring to light real tendencies – especially due to the diversity and even corresponding phytotoxicity interventions that may be induced in these examples. Globally viewed the purpose remains to promote successful weed control continually in the most environ- mentally friendly way possible – a stiuation in which chemical weed control strategies may be satisfactorily feasible, emphasising that scientifically based guidelines must be closely pursued in the application thereof.

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