Characterization of Root-knot Nematodes (Meloidogyne spp.) Associated with Abelmoschus esculentus, Celosia argentea and Corchorus olitorius

Abstract

Vegetable crops are highly susceptible to a wide range of pests and diseases among which are the root-knot nematodes (Meloidogyne species). Traditionally, identification of Meloidogyne species had been based on use of morphological characters such as the perennial pattern. In recent times, accuracy of nematode identification using only morphological tools has been challenged due to similarities in morphological characters of some nematode species. The aim of this study was to identify the root-knot nematodes associated with some vegetable crops cultivated on Covenant University farm, Ota, South-west, Nigeria using molecular tools and to determine the population densities of Meloidogyne spp. on the selected vegetable crops. Plant-parasitic nematodes were extracted from soil and roots of Abelmoschus esculentus, Celosia argentea and Corchorus olitorius cultivated on Covenant University farm. The nematode species were identified and counted under a compound microscope. The molecular characterization of the Meloidogyne species was done using single adult female nematodes and eggs which were picked out for DNA extraction and amplified with specie-specific primers through Polymerase Chain Reaction (PCR) and separated on 0.5% agarose gel. High population of plant-parasitic nematodes was recorded on the vegetable crops cultivated on covenant university farm. Also significantly higher population (p<0.005) o f Meloidogyne spp. were found in association with C. argentea and Corchorus olitorius than those recorded on Abelmoschus esculentus from the vegetable farm. The molecular characterization of the Meloidogyne species from the farm indicates Meloidogyne incognita as the nematode species associated with the vegetable crops.

Parasitism of the root knot nematode Meloidogyne incognita (Kofoid and White) chitwood in five wild Solanaceae species

“…The high inter and intra-specific variability in the Meloidogyne populations favors their adaptability and gives greater selective advantages over their hosts, being several Solanaceae species host of this nematode (González et al, 2010) how was observed in this study. Host-plant resistance to plant-parasitic nematodes is defined as the suppressive effect of the plant on the nematode's ability to reproduce (Cook and Evans, 1987). This definition of resistance in terms of reproduction of the nematode has been adopted by plant nematologists (Cook, 1974).…”

“…There are more than 90 species of Meloidogyne identified, however M. arenaria, M. javanica, M. hapla and M. incognita are the most important because they cause major economic damage (De Jin et al, 2005;. Plants affected by nematodes showed symptomatology such as leaf yellowing, less growth and wilting and limited root development because of the formation of root knots, affecting the absorption of nutrients and decreasing yield (Daramola et al, 2015). Nematodes can interact with other diseases (i.e.…”

Selection of resistant rootstocks to Meloidogyne enterolobii and M. incognita for okra (Abelmoschus esculentus L. Moench)

“…Galls develop in the infected roots from the formation of giant cells used by this parasitoid as a source of nutrients. These modified cells can interfere with the flow of water and nutrients within plants, resulting in crop yield reductions or even the total loss of the crop (Daramola et al, 2015). Hussain et al (2011) found that an impaired development of okra was directly proportional to the initial nematode population density, yet inversely proportional to the age of the plant.…”

Comparative Effect of Rotylenchulus reniformis and Meloidogyne incognita on the Productivity of okra in Nigeria

“…Reniforn nematodes causes severe damage to roots (Koenning et al, 1996). Daramola et al (2015) found relatively high populations associated with okra fields in the same state where the field experiments for this study were conducted. This implies that nemematode is probably widespread in parts of south western Nigeria and may go unnoticed as a pest of vegetable crops due to the apparent lack of root symptoms.…”

“…R. reniformis is usually found in mixed populations with M. incognita and the disease symptoms in such situation is often only associated with root-knot nematodes. Many authors in Nigeria have found the reniform nematode in moderate populations associated with various crops (Adegbite et al, 2006;Olabiyi et al, 2009;Afolami et al, 2014;Daramola et al, 2015) but they did not consider the nematode to be damaging. This implies that the reniform nematode can be present in damaging populations and be left undiagnosed and uncontrolled due to lack of association as a potential pest problem.…”