The beet cyst nematode (Heterodera schachtii) can cause considerable yield loss in brassica vegetable crops (cabbages, Chinese cabbages, cauliflowers, Brussels sprouts, broccoli, turnip, radish and swede), as well as to beets (red and silver), rhubarb and spinach, by severely damaging root systems, especially during summer. This nematode also infects many common weeds such as wild turnip, shepherd’s purse, fat-hen and portulaca.
Entire fields can be infested, but infestations are most often in localised patches. Natural movement is limited so spread is often in an elliptical pattern of poorly growing plants in the direction of machinery movement. Over time, the smaller areas of infestation will enlarge and spread.
Beet cyst nematode can parasitise plants of all ages. Seedling attack can result in severe injury or even plant death. Damage is less notable when older plants are attacked.
Nematodes feed on plant roots, reducing the plant’s ability to take up nutrients and water. Therefore above-ground symptoms look like nutrient deficiency or drought — reduced stand, poor growth, stunting, yellowing and wilting (Figure 1).
An infested crop contains smaller plants of reduced value and quality and will compete poorly with weeds.
Roots attacked by beet cyst nematode often appear ‘bearded’ or ‘whiskered’ due to excessive development of fibrous roots as the plant attempts to combat nematode damage. Impacted root vegetables have smaller storage roots and may also develop abnormal swellings or lumps.
The most evident sign of beet cyst nematode is the appearance of glistening white-yellow bodies about the size of a pin head attached to the fibrous roots. These mature and harden to produce a light-brown to reddish-brown cyst (Figure 2).