Phenological stage of development – inflorescence separation – flowering

Pest – Downy mildew of grapevine Plasmopara viticola

Damage

The disease most frequently attacks leaves and clusters. The manifestation of the disease on infected leaves is expressed in the formation of pale green, round (oily) spots. In humid weather, the spots on the underside of the leaf are covered with a greyish-white mould. When the cluster is infected immediately after flowering, the young berries darken, become covered with a greyish-white coating and dry up.

Control

The first treatment is carried out when favourable conditions for infection occur (air temperature above 13°C, frequent but light rainfall) and a susceptible phenological stage of the vine (“flowering” - “pea-size berry”). The aim is to treat before the appearance of oily spots on the leaves. When using contact fungicides, the intervals between sprays are 3-7 days, for locally systemic fungicides 7-10 days, and for systemic fungicides 10-14 days.

Pest – Powdery mildew Oidium tuckeri

Damage

The disease manifests mainly on the upper side of the leaves, where yellowish-green spots with a greyish-white coating are formed. When the clusters are attacked after flowering, small spots covered with a white coating are formed on the berries. 

Control

The first preventive spraying should be carried out when the shoots reach a length of 10-15 cm. Subsequent treatments should be carried out every 8-10 days, depending on climatic conditions, cultivar susceptibility, degree of infestation and the mode of action of the fungicide used.

Pest – Grey mould Botrytis cinerea

Damage

The damage to the inflorescences is expressed in the browning of the flower buds, which subsequently dry up and fall off.

Control

In warm and humid weather, immediately after flowering, a preventive spraying should be carried out with one of the registered fungicides.

Pests

Pest – European grapevine moth Lobesia  botrana

Damage

In May, the larvae of the first generation of the pest cause damage by gnawing the flower buds and webbing them together with silk threads. The larvae often gnaw the branches of the inflorescence, thereby causing the death of many more flower buds.

Control

A treatment should be carried out at the beginning of larval hatching when the economic threshold of harmfulness for the first generation is reached:

• table grape cultivars - 4-6 larvae per 100 inflorescences;

• wine grape cultivars - 6-8 larvae per 100 inflorescences.

Pest – Vine scale  Pulvinaria vitis

Damage

During this period, the larvae of the overwintering generation and the vine scales that have developed into adults cause damage. They suck sap from the shoots, which results in the weakening of the vines.

Control

Chemical control is carried out against the young larvae with one of the registered plant protection products.

Pest – Yellow grapevine mite Schizotetranychus viticola and European red mite  Panonychus  ulmi

Damage

Adults, larvae, protonymphs and deutonymphs of the first and second generation of both species cause damage by sucking sap from the underside of the leaves, grouped mainly around the main and secondary veins.

Control

A treatment should be carried out against adults and larvae when the economic threshold of harmfulness is reached:

• 2-3 individuals/leaf - until mid-May.

Pest – Cigar-bearer weevil Byctiscus betulae

Damage

The adult insects cause damage by initially gnawing the buds and later the leaves and shoots.  During oviposition, the females gnaw the petioles of the leaves or the young shoots and, after the leaves wilt, they roll them up in the form of a cigar.

Control

If an increase in the density of adults is established, treatment should be carried out before oviposition with contact insecticides.

Spraying is repeated after 10-14 days.