Comparison of two methods for in vitro multiplication of Radopholus similis and Pratylenchus brachyurus in carrot cylinders

Abstract

The use of in vitro mass multiplication of nematodes under axenic conditions allows intensification of studies on taxonomy, biology, epidemiology and control of these pathogens. In the present study, two methods were compared for in vitro multiplication of two species of plant-parasitic nematodes, Radopholus similis and Pratylenchus brachyurus in 20, 40 and 60 day-periods. Both techniques involved the use of carrot cylinders placed in jars with lids, with water-agar in the bottom of the flasks (WA+) or without (WA-). In WA- the nematodes were treated with a 1% solution of ampicillin whilst for WA+ the axenization was carried out with a solution of mercuric chloride (0.01%), and streptomycin sulfate 0.02%. The WA+ condition was the most favorable for multiplication of both species of nematodes, resulting in a population increase of about 280 times for R. similis and 226 times for P. brachyurus in relation to the founding population of 25 individuals. For WA- a population increase of only five times after 60 days for R. similis and a duplication of the population after 60 days for P. brachyurus was obtained. Overall, the largest amount of nematodes occurred at 60 days after inoculation

The Ethiopian staple food crop enset (Ensete ventricosum) assessed for the first time for resistance against the root-lesion nematode Pratylenchus goodeyi

“…Due to there being no monoxenic cultures of P. goodeyi available, naturally infected roots were used as inoculum, which has previously been shown to be a successful alternative (Coyne et al, 2010). Monoxenic culturing of some species of Pratylenchus is also not always successful using the conventional method on carrot discs (Santos et al, 2012), and P. goodeyi has proved difficult to date (Coyne, pers. comm.).…”

Cocoyam (Colocasia esculenta) provides an effective monoxenic culture media for Radopholus similis

“…O'Bannon & Taylor (1968) developed the sterile carrot disc technique for the monoxenic culture of R. similis to support such routine research activities. This technique has since been adapted and employed for the monoxenic culture of a few root-lesion nematodes (see Kagoda et al, 2010;Santos et al, 2012). However, not all species are well adapted to this technique with some requiring months to develop, such as Pratylenchus sudanensis (Mudiope et al, 2004), and others proving unsuccessful, such as Helicotylenchus multicinctus (Speijer & De Waele, 1997).…”

“…The R. similis multiplication in the current study compares with 280 times after 60 days using 20 mm × 15 mm diam. carrot discs in an improved method using a water agar combination (Santos et al, 2012). When assessing the use of in vitro alfalfa callus, Elsen et al (2001) achieved a R. similis reproduction ratio of 223 after 12 weeks.…”