Occurrence of mixed populations of root-knot nematodes in vegetable greenhouses in Turkey, as determined by PCR screening

Abstract

Root-knot nematodes are major agricultural pests that attack a wide range of crops around the world. They are endoparasitic pathogens that cause galls on roots, preventing sufficient water and nutrient uptake by plants. Therefore, heavily infected plants can die from additional biotic and abiotic stresses. Meloidogyne incognita, M. javanica and M. arenaria are commonly present in vegetable growing fields in Turkey. Rapid and accurate detection of such pests are highly important for implementing sustainable crop rotations and effective integrated pest management strategies in fields because they may exist as mixed populations. In the present study, 300 plant root and 300 soil samples were collected from greenhouses located in Kumluca, a significant protected vegetable production area in Turkey. Egg masses and second-stage juveniles (J2) were obtained from plant root and soil samples, respectively, and DNA isolated from these two sample types was used in PCR assays. The occurrence rates of Meloidogyne spp. varied according to the DNA isolated from egg masses and J2s in soil samples. All egg masses contained M. incognita, 50% contained M. javanica and 41% M. arenaria. Seventy-three per cent of the soil samples contained J2 of M. incognita, while 55% contained M. javanica and 4% M. arenaria J2. Our data showed the existence of mixed root-knot nematode populations in the vegetable growing fields of this region. These findings present a great opportunity to select the correct crop for the area and efficiently utilise available resistant genes for management practices.