Pest control system for cucumbers, onions and cabbage in June

Cucumbers

Pest – Cucumber downy mildew Peronospora cubensis

Damage

The first symptoms appear on the lowest leaves. On the upper side of the leaves, yellowish spots of varying size are observed. On the underside, the spots are covered with a sparse violet-grey mould.

Control

Fields should be regularly inspected, especially those located in low, poorly ventilated areas and those near rivers. At the first symptoms, treat with systemic fungicides at 7-day intervals.

Pest – Powdery mildew on cucumber Sphaerotheca fuliginea

Damage

Small round spots covered with white powdery growth appear on the leaves. In some cases the spots may be on the upper, and in other cases on the lower side of the leaves.

Control

Upon occurrence of symptoms, treatments should be carried out at 12-day intervals until the development of the disease is limited, using one of the registered fungicides.

Pest – Angular leaf spot (Bacterial blight) Pseudomonas syringae pv. lacrymans

Damage

Oily angular spots develop on the leaves, delimited by the veins. At high humidity, the spots on the underside of the leaves are covered with yellow, turbid droplets of bacterial exudate.

Control

Monitor for the occurrence of the disease, especially after heavy rain accompanied by wind or after hail. Upon establishing initial occurrence, treat with contact plant protection products. 

Onion

Pest – Leek leaf miner fly Napomyza gymnostoma

Damage

Damage is caused by the newly hatched larvae. They feed on the parenchyma without affecting the epidermis. The formed mines are almost straight, directed towards the base of the plants. In leek, the larvae penetrate into the inner sheath leaves of the stems.

Control

In June, a mass flight of the flies of the second generation of the pest is expected. To prevent infestation of the field, the seedlings should be treated one week before transplanting, and under field conditions – 10 to 12 days after transplanting.

Pest – Downy mildew Peronospora destructor

Damage

In the presence of local rainfall and in weedy areas where moisture remains for a longer period, the risk of disease manifestation persists.

Control

In the presence of diseased plants, authorised plant protection products with systemic action should be used.

Cabbage

Pest – Aphids fam. Aphididae

Damage

Aphids suck sap from the leaves and apical parts of the plants. They become discoloured, curl and lag in their development. Cabbage with severely damaged young leaves does not form heads.

Control

Before transplanting the cabbage, cruciferous weeds should be destroyed. Treatment should be carried out at an economic injury threshold: 5% infested plants in medium-early cabbage;

Pest – Cabbage flea beetles Phyllotreta sp.

Damage

Under heavy infestation, the leaves are severely perforated, turn white and dry out. In sunny and warm weather, the damage is significant.

Control

Treatment should be undertaken during the vegetation period at an economic injury threshold: 10% destroyed leaf area.

Pest – Cabbage moth Mamestra brassicae

Damage

Initially, the caterpillars feed on the underside of the leaves, gnawing them. Later they bore tunnels in the cabbage heads and fill them with excrement. In cauliflower they gnaw the inflorescence.

Control

Chemical treatment should be carried out at the following economic injury thresholds: -

• 12–15 caterpillars per 100 plants in medium-early cabbage;

•  5 caterpillars per 100 plants in cauliflower;

When treating allium and brassica crops, an adjuvant should be added!