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Potatoes | Plant Magic
Soil Pests and Diseases Nutrients

Posted By: Plant Magic

Pests and Diseases That Affect Potatoes

Potatoes are an extremely versatile vegetable that can be grown from spring to autumn outdoors and given hydroponic nutrients for the best possible growing conditions. Certain pests and diseases can affect these vegetables and kill the plants, spreading to other healthy plants if not found on time.

Knowing how to grow potatoes is more than simply addressing pests like aphids, which are easily treated with an environmentally friendly Bugicide. There are some more serious diseases to keep an eye on for healthy potatoes.


Potato Scabs

Potato scabs, common scab and powdery scab, occur in the summer due to both an organism that is closely related to slime moulds and due to filamentous bacteria. Common scab causes rough and raised patches of skin on the surface of tubers and powdery scab causes areas with dusty brown spores and irregular brown raised areas.

When tubers are developing, the soil can’t be allowed to dry. Organic matter levels such be increased for better water retention or additional watering may be needed. Alkaline soils make common scab worse, and it’s vital to apply lime to the soil.

Our recommendation: A Bio Wetter product as a soil drench to improve absorption.


Potato Blight

Affecting both potato and tomato plants, potato blight is an organism similar to a fungus, affecting plants from early-summer and onwards. It causes symptoms such as shrivelled leaves and brown rotting, with the initial effects of the blight spreading rapidly. A watery rotting of the leaves will occur, which proceed to collapse, shrivel, and become brown.

Potato blight can reach the tubers, which become reddish-brown due to decay and eventually become soft with the tissues rotting away.

Our recommendation: Essence Leaf-Disease Cure to fight against airborne pathogenic fungi.

Rotten Potatoes | Plant Magic


Cutworm caterpillars are a variety of moths living in the soil, with a grey-brown colour and growing up to 40mm. They feed on potato plants’ stems and cause crops to collapse. The turnip moth (Agrotis segetum), the heart and dart moth (Agrotis exclamationis), and the large yellow underwing (Noctua pronuba) are the most common that cause damage in gardens.

Should the weather be mild at night, cutworms can be seen feeding on low-growing herbaceous plant leaves. When plants wilt due to cutworms, these caterpillars can easily be found under the plant.

Our recommendation: Protect plant stems with Hydro Silicon.


Potato Cyst Eelworms

Caused by parasitic nematodes, potato cyst eelworms can also affect tomatoes and aubergines. This phylum of animals similar to worms occur commonly in Britain through the species of golden or yellow cyst eelworms (Globodera rostochiensis) and through the species of white cyst eelworms (Globodera pallida).

Potato cyst eelworms feed on potato roots and can quickly decimate a crop. These microscopic organisms are usually between 1-1.5mm long, which can be seen when an affected plant is carefully lifted.

The best way to avoid this pest is to rotate crops and to not grow potatoes or tomatoes in the same area of soil too frequently. Symptoms of potato cyst eelworms include extremely small and spherical cysts on the roots which contain hundreds of eggs each. Plants that heavily infected will die prematurely and produce tubers that are smaller than expected.

Our recommendation: Bugicide helps with a variety of pests and mildew.


Potato Tuber Rots

Common causes of potato plants dying before or after lifting, potato tuber rots can include gangrene, blackleg or bacterial soft rot, pink rot, blight, or dry rot. Gangrene develops during storage with ‘thumb-mark’ lesions appearing on potatoes’ surfaces and extensive internal lesions.

Pink rot is apparent when lifted tubers have soil sticking to them and discoloured skin patches. The flesh of the potatoes becomes watery and rubbery, becoming pink with air exposure and smelling of vinegar. Dry rot symptoms develop in storage with the skin having brown patches that correspond to internal cavities that are lined with fungal growth.

Our recommendation: Evolution will help your plants to recover from pest attacks.

Baby Potatoes | Plant Magic

Potato Blackleg

This common potato bacterial disease causes black rotting at stem base, yellowing stems, and stunted growth. Potato blackleg can be seen as early as June in outdoor crops, with the leaves of potato plants being curled inwards, small, and stiff. Tubers that grow after the plants are infected often have a brown or grey, rotten flesh.

As this disease thrives in damp and warm conditions, make sure that the soil can drain properly and lift crops when the weather is dry.

Our recommendation: Protect plant stems with Hydro Silicon.

If you want to know more about our products for healthy and sturdy crops, make sure to get in touch with our team by giving us a call on 01695 554 080. We know more than just when to plant potatoes - we’ll happily advise you on any problem solvers you may need.

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Whether you are an expert who already has a thriving crop of healthy plants, or you are trying to grow your very first hydroponic yield, we can help you to grow the strong and healthy crops you have always wanted.

Here at Plant Magic Plus, our team of gardening experts work very hard behind the scenes to provide you with the high quality nutrients, additives and growing media that will help you to get the most out of your growing plants.

But we understand that successful horticulture is about more than just having good quality chemicals, nutrients or fetilisers, that's why we have written this blog to provide you with the insights, tips and techniques you will need to give your garden that extra magic touch.

From helpful advice about watering your plants in soil and a guide to magnesium nutrients, to top tips about growing hydroponic vegetables and a comprehensive overview of microbes, we’ve got everything covered.


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