Pest control system for potatoes in June

Pest – Late blight of potato Phytophthora infestans

Damage

Favourable conditions for infections and rapid development of the disease are created when minimum temperatures are optimised and there are frequent precipitations during the flowering period.

Control

In case of established infection, systemic fungicides should be used. Within one growing season, one product or a group of products with the same mechanism of action shall not be applied more than three times.

Pest – Early blight (Alternaria) Alternaria solani

Damage

The pathogen overwinters in infected plant residues. It develops intensively at an optimal temperature of 22-26°C, accompanied by heavy dews and short showers.

Control

Control of the disease should be carried out simultaneously with the control of late blight of potato using one of the registered plant protection products.

Pest – Rhizoctonia (Black scurf) Rhizoctonia solani

Damage

At the base of the stem and on the roots, reddish-brown spots are observed, which later turn into cankers. Under moist conditions, a white mycelial growth is formed, which covers the stem like a sheath.

Control

Conditions for the development of the disease are created when potatoes are grown on heavy soils, at high temperatures and when crop rotation is not observed.

Pest – Ring rot Clavibacter michiganensis subsp sepedonicus

Damage

After flowering, the plants slowly wilt. The leaf margins curl upwards in a spoon-like shape, the surface loses its gloss, the leaves turn yellow and later become necrotic. The stems crack and become discoloured; when cut transversely, an oily exudate oozes from the tissues.

Control

Monitoring of potato fields should start from the phenological stage “flowering”. Plants showing symptoms of ring rot should be monitored. In case of suspicion or symptoms of the disease, the Regional Food Safety Directorates shall be notified.

Pest – Colorado potato beetle Leptinotarsa decemlineata

Damage

During the period, damage is caused by the larvae and the overwintered adults. The larvae have four instars. First-instar larvae scrape off the lower epidermis and parenchyma. Second-instar larvae feed on the soft parts of the leaves. The most voracious and with the longest development are the fourth-instar larvae. They feed day and night, and in rainy weather they hide under the leaves and in soil cracks.

Control

Chemical control should be carried out at the following economic injury levels: for adults – 5 adults per 100 plants at a plant height of 15-25 cm; 10 egg clusters per 10 plants at a plant height of 15-25 cm; for larvae – 150 larvae per 100 plants at a plant height of 15-25 cm; 10% infested plants at the phenological stage “bud formation”.

Pest – Aphids fam. Aphididae

Damage

On potatoes, aphids suck sap from the underside of the leaves. The danger from them is much greater as vectors of viral diseases. With an increased concentration of nitrogen in the plants, aphid reproduction is accelerated.

Control

Fields should be regularly inspected. Chemical treatment should be carried out at the following economic injury levels:

•   2-5% infested plants – for table potatoes;

• single specimens – for seed potatoes