An experiment was conducted in the Department of Biological Sciences, Federal University Dutsinma, Katsina State Nigeria, between May to August, 2016. A survey was carried out from three farm areas around Dutsin-Ma Metropolis to investigate and determine the incidence and population of plant parasitic nematodes of green amaranth (Amaranthus hybridus L.). A total of 240 soil root samples from an infested A. hybridus were taken 10 cm deep from the rhizosphere of the green amaranth plant. The samples were extracted using Cobb-Seiving and Decanting Method. From the supernatants residue, a total of nine genera of plant parasitic nematodes were identified, with 6 genera in Farm 1, 8 genera in Farm 2, and 5 genera in Farm 3. The genera Meloidogyne (23.33%), has the highest incidence followed by Xiphinema (14.58%), Pratylenchus (13.33%), Heterodera (10.83%), Paratrichodorus (10.83%), Aphelenchoides (9.16%), Helicotylenchus (8.33%), Tylenchorhychus (7.92%) and Longidorus (7.08%). Data on incidence from root galling was also taken from the examined samples, with Farm 2 having highest value for moderate root gall damage. It has been deduced from the result that most of the plants with high parasitic load of the nematodes exhibit root gall, chlorotic and perforated leaves, darker weak stems, stunted growth and poor flowering. This results shows that there is a widespread distribution of plant parasitic nematodes against the A. hybridus plants in the surveyed areas (Farm 1, 2 and 3). The presence of these parasitic nematodes, even at low populations in the soil is not significant (P > 0.05) in comparison with all the root samples from the three selected farms (F = 0.12, P = 0.8803). The parasitic nematode population built up could eventually result in great reduction of the crop yield. Establishing efficient research control on the damaging potentials of these parasitic nematodes as against this vegetable crop; hence, awareness programs ought to be created for researchers, farmers and lay men.
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