Prepare soil for planting

What are free living nematodes?

FLNs are parasitic soil borne pests which feed on the roots of potato crops, reducing crop yield quality.  They can also transmit viruses. FLNs are most often found in sandy and light open-textured soils, and they reproduce very quickly when soil temperatures are between 15°C and 30°C.

Free-living nematode damage to potato crops 

FLNs are particularly damaging to potatoes because they transmit a virus called Tobacco rattle virus (TRV), causing spraing, a tuber disorder. As spraing affects tuber quality, it can make potatoes unsaleable. If spraing is present, you will notice brown flecks, circles or lines through the tuber as well as short stems and discoloured leaves. 

Free-living nematode control 

To reduce the threat of FLNs to your potato crop, take an integrated approach to soil pest management.  As well as using soil testing to monitor FLN populations, use NEMATHORIN to control spraing transmitted by free living nematodes in potatoes. 

What are wireworms?

Wireworms are the larvae of click beetles. They are soil pests which feed on and burrow into plant roots and tubers all-year round for 4-5 years before they pupate. Even relatively low populations can cause significant damage to potato crops.

Wireworm damage in potatoes

If there are wireworms in potatoes, there will be small, round holes on the surface of potato tubers which lead to narrow tunnels. This damage can result in yield loss, seedling death, and a considerably less marketable potato crop. 

Wireworm control 

To prevent wireworm damage in potatoes, there are several things you can do. 

• Control weeds as they can be an extra food source for wireworms. 
• Consider lifting your potato crop early if you expect a problem with wireworms.
• Use soil sampling to get an idea of the population size. 
• Use a proven treatment such as NEMATHORIN, which reduces wireworm tuber damage. 

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What is silver scurf in potatoes?

Silver scurf is a seed-borne disease of potato tubers caused by the fungus Helminthosporium solani. Symptoms of silver scurf include tan or grey lesions which start at the stem end of the tuber surface, making it appear ‘shiny’ when wet. Infection can originate in infested soil, infected seed potatoes, or infected tubers in storage. The disease usually spreads when rain or irrigation disperses fungal spores through the soil. Once in storage, high temperatures and humidity encourage the disease to develop.

Silver scurf damage

Silver scurf infection damages the skin of potato tubers. This affects their quality and appearance, sometimes making them unmarketable. 

Silver scurf control 

Early lifting can reduce the risk of silver scurf infection as can getting out in the field and checking tubers for signs of the disease. Treating tubers with a fungicide before planting or at harvest when they are in store can prevent infection. Keeping stores clean and well-ventilated can also help. 

Black dot is a soil-borne and tuber-borne disease caused by the fungus Colletotrichum coccodes. The fungus enters potato plants through injured leaves or stems, or via underground stems. Black dot is often mistaken for early blight as it shares similar symptoms, namely wilting and nutrient deficiencies. It is more likely that it is black dot in your potato crop if you see mid-late summer yellowing and wilting of the top leaves in the canopy and tiny sclerotia on stems, tubers, stolons, and roots. At the end of the season, you can identify black dot on your potato crop by checking lower stems and petioles for silvery black lesions. 

Black dot in potatoes damage

While black dot is a mild disease which won’t kill potato plants, it does have an impact on plant health by making them vulnerable to other diseases. Black dot can also affect tuber size, weight, and crop yield quality. 

Controlling black dot in potatoes

An integrated approach which includes the management of crop pests is the best way to prevent black dot infections. An early-season application of a fungicide, focusing on the plant stems plus planting in well-drained soils can help. You should rely on the principles of good crop management to protect your potatoes; carry out visual checks out in the field, ensure crops have enough nutrients and water, and manage other pests. 

Common scab in potatoes is caused by Streptomyces scabiei bacteria. The bacteria are soil-borne, thrive in dry soils, and invade through the tuber skin during early development. If bacteria are present, a common scab potato will have an unpleasant looking brown discolouration of the tuber skin. This may appear as raised spots or it can cover the entire tuber surface. 

Common scab damage

The disease won’t have much of an effect on yield or storability, however quality can be affected due to the scab lesions. 

Controlling common scab 

Maintain soil moisture levels and plant scab-free tubers, ideally resistant varieties. Apply a seed treatment like MAXIM 100FS to combat the disease in the field. 

What is Rhizoctonia fungus?

Rhizoctonia solani is a common seed- and soil-borne fungus. It’s responsible for causing black scurf on tubers and stem and stolon canker on underground stems and stolons. The fungus thrives in cold and wet soils, and it will grow faster than potato plants in these conditions. Rhizoctonia solani symptoms include reddish-brown lesions on stems near ground level. In some cases, the lesions are present on stolons and can pinch off sprouts before the plants emerge, which can result in the loss of the tuber. Another tell-tale sign of the presence of Rhizoctonia in potatoes is black scurf. You’ll see sclerotia (hard black masses) form on the skin which won’t easily wash off. 

Rhizoctonia damage 

Rhizoctonia can cause yield losses due to stunted plants. Quality is also affected because the disease causes the tubers to become discoloured and/or misshapen. 

Controlling Rhizoctonia in potatoes 

Management of Rhizoctonia requires an integrated approach. To reduce incidence of disease, plant shallow into warm soil, starting with coarse-textured soil. Increasing the amount of soil organic matter can reduce the risk of disease as can treating tubers with a fungicide such as AMISTAR.