Root lesion nematodes
Root lesion nematodes (Pratylenchus spp.) can multiply in a wide range of crops. Not all crops are harmed. Root lesion nematodes cause growth inhibition and root rot in a number of crops. In addition, the nematodes intensify the effect of early wilting disease (Verticillium dahliae) and scab (Rhizoctonia). Besides interacting with these fungi, damage to the roots makes the plant more susceptible to other pathogens. Root lesion nematodes occur mainly on sandy, valley and light sandy soils. Often, multiple root lesion nematodes occur together. Pratylenchus penetrans is the main damage agent in Dutch arable farming and horticulture.
The nematodes penetrate the root and make their way deep into the root. The cells the nematodes pass through are sucked dry and die. This can be seen on the outside by brown spots (lesions). The nematodes remain mobile throughout their lives and can leave the dying roots and infest new roots. The eggs are laid loose in the soil or in the roots. Pratylenchus penetrans lays 1-2 eggs per day for five weeks. The eggs hatch after 9 to 25 days, depending on the temperature. Root lesion nematodes have a short life cycle and there are two to three generations per year.