Pest control and fertilisation with grapevines
So far vine cultivation has given rise to a good number of grape varieties that are hardy against true mildew (Oidium) and false mildew (Peronospora). Some of these varieties are among other reasons, for their attractive fruit particularly propagated for dessert grapes, but can also be used for wine grapes.
If, against all expectation, slight fungal infestation should be observed in these new varieties, this can as a rule be ignored, as it involves a late infestation which merely detracts from the plants appearance while having no damaging effect on either the fruit or the plant itself.
In general, insect pests are of no importance. Being grafted onto a resistant host and one should only plant such vines the scion vine will remain resistant to vine pest throughout its whole life.
Let it be said from the start that vines grown against the house and in the garden usually manage perfectly well without special fertilisation and, providing another vigorously growing plant is not in the close vicinity, their roots spread widely to obtain nourishment from the surrounding soil. However, if there are first indications of a slackening of growth, it is appropriate to apply a moderate amount of a general fertiliser, although not in the immediate vicinity of the spot where the vine was planted.
Please note: the use of mineral fertilisers is often exaggerated. One-sided nitrogen-based fertilisation encourages fungal diseases, slows down the maturation of the wood and thus makes freezing in winter more likely.