Infection of Cotton Seedlings By Meloidogyne Incognita and a Method of Producing Uniformly Infected Root Segments

Abstract

Larvae of Meloidogyne incognita failed to penetrate root tissues 4 cm from the root tip and only a few penetrated 2 cm from the tip. Following penetration, larvae initially became oriented acropetally, parallel to the stele and could migrate up to 12 mm towards the growing tip. However, by 32 hr they were randomly oriented. The inoculation procedure utilized assures uniform, synchronous penetration of cotton roots by these nematodes.

effect of some insecticides, natural compounds and tomato cv. Venezia with Mi gene on the nematode Meloidogyne ethiopica (Nematoda) reproduction

“…The tubes were centrifuged at 1500 rpm for 5 min. The pellets which contained the eggs and plant tissues were re-suspended in 40 ml of sucrose solution (454 g sucrose per 1 liter of tap water) and centrifuged at 1000 rpm for 1 min (McClure et al, 1973). The supernatants were poured through 32 µm banked sieve and washed with 200 ml tap water.…”

Increased penetration of host roots by nematodes after recovery from quiescence induced by root cap exudate

“…Seeds were germinated at 24 • C on 1.0% water agar overlaid with sterilised germination paper as described by Hawes (1990), until roots were ca 20 mm in length. For infection experiments, 30-40 seeds were placed 0.5 cm apart into autoclaved 'rag dolls', prepared by placing three layers of moistened germination paper loosely rolled together with autoclavable plastic wrap (McClure & Robertson, 1973). Rag dolls were placed upright in beakers then incubated at 28 • C in the dark.…”

“…To obtain J2, eggs were placed in distilled water above a 20 µm nylon fibre screen. J2 were collected 2 days later following procedures described by McClure and Robertson (1973). Ditylenchus dipsaci was cultured on alfalfa seedlings growing on Gamborg's B5 basal medium with 2% agar (Gamborg et al, 1968).…”