Potato rot nematode

Potato rot nematode

Ditylenchus destructor

Common name:

Potato rot nematode

Scientific name:

Ditylenchus destructor

Alternative common names:


Potato rot nematode is a tiny roundworm that can cause significant damage to the underground parts (roots, tubers, bulbs) of host crops. Such crops include potatoes, sugar beets, carrots and garlic. It can reduce harvest yields of host crops and cause additional damage during storage. In South Africa, nematodes are often referred to as eel- or roundworms because they resemble the common earthworm, but these parasites belong to a different grouping or phylum.

Additional Information

Where does this species come from?

United States of America.

What is its invasive status in South Africa?

NEMBA Category 1b.

Where in South Africa is it a problem?

Mpumalanga, Free State, North West, Northern Cape, Limpopo.

How does it spread?

Spreads through infested planting material, movement of soil, and water.

Why is it a problem?

Can reduce harvest yields of host crops, cause additional damage during storage and affect international trade of certain commodities (especially potatoes). Once established, it is almost impossible to eliminate because it can survive on a range of other hosts and soil fungi.

What does it look like?

Description: Potato rot nematode is regarded as being of microscopic size, although a few species can be seen without magnification. Most plant-parasitic nematodes are in the range of 1.4mm in length. A great many nematodes have a worm-like or eel-like shape. Females of some kinds grow swollen at maturity and resemble tiny beans, lemons, or pears.

Habitat: These nematodes live inside living tissue, where they aggregate rapidly. They survive in stored tubers during winter and can infect the stolons of planting material. The soil plays only a secondary role in the transfer of this nematode.

Breeding: The biological cycle takes place in tubers, where the nematodes eat starch grains. As a result, the affected tissue becomes powdery and brown and the tuber surface is covered with dark spots and becomes dry and cracked. The nematodes aggregate abundantly because of the high fertility of females (up to 250 eggs) and short cycle of development (15-45 days).

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