Root lesion nematodes (RLN) are microscopic, worm-like organisms that feed on and damage plant roots, thus affecting crop yield. In the western region, RLN are often associated with patchy, unthrifty cereal crops. The key to managing them is to identify paddocks with yield-limiting numbers present, then incorporate resistant crops and varieties into rotations to reduce their number.

Key Points

• RLN are found in approximately 6.25 million hectares (or 80 per cent) of the WA winter broadacre cropping area. Populations potentially limit yield in at least half of these infested paddocks
• The main RLN species found in WA broadacre cropping are Pratylenchus neglectus, P. quasitereoides (formerly known as P. teres), P. thornei and P. penetrans
• The host range of RLN is broad and includes cereals, oilseeds, grain legumes and pastures, as well as many broadleaf and grass weeds
• A soil test prior to sowing can identify the number of RLN species present in a paddock and thereby inform crop and variety choice. In-crop soil testing can be used to identify the cause of crop symptoms
• Crop rotations using resistant crops/varieties or pasture species are recommended to reduce RLN population densities and minimise yield losses in subsequent crops
• Western region barley and wheat variety guides give P. neglectus and P. quasitereoides resistance ratings for commonly grown varieties