Evaluating Pochonia chlamydosporia in a double‐cropping system of lettuce and tomato in plastic houses infested with Meloidogyne javanica

Abstract

The effect of Pochonia chlamydosporia , a facultative fungal parasite of nematode eggs, alone or in combination with oxamyl was evaluated in a double-cropping system of lettuce and tomato in unheated plastic houses infested with Meloidogyne javanica at two sites for two consecutive growing seasons. An additional treatment of methyl bromide fumigation was included to compare crop yield in nematode-free vs. nematode-infested soil. Final population densities, reproductive rate, root gall rating, and egg production were determined after each crop. Pochonia chlamydosporia was isolated from nematode eggs up to nine months after application to soil. The fungus survived in the rhizosphere for the entire growing season at one site, but only at low densities. Final population densities of M. javanica decreased after cultivation of lettuce and increased after tomato, and this pattern of population fluctuation was unaffected by treatment, experiment or site. The reproductive rate on lettuce was equal to or below 1, and it was similar among treatments in both experiments at both sites. Eggs were not found on lettuce roots. On tomato, the reproductive rate in the fungus + oxamyl treatment was significantly lower ( P < 0·05) than other treatments in experiment 1 at both sites. Fungus + oxamyl consistently reduced root gall ratings on tomato in all cases, but numbers of eggs per g root varied depending on treatment. Methyl bromide-treated plots remained free of M. javanica at the end of the 2-year study.

Effectiveness and profitability of the Mi-resistant tomatoes to control root-knot nematodes

“…Lettuce, Lactuca sativa type Maravilla cv. Arena, rotated with tomato from October to February, did not support nematode reproduction (Verdejo-Lucas et al, 2003).…”

“…Observation of these premises resulted in undetectable root-knot nematode levels in plastic-houses for at least 2 years (Verdejo- Lucas et al, 2003), although the nematode can be found in methyl bromide fumigated soils after cultivation of a single crop . Since agriculture is an economic activity, any control method can only be justified if the increased value of the crop is equal or greater than the cost of the control method.…”

In vitro soil receptivity assays to egg-parasitic nematophagous fungi

“…In biological control experiments of root-knot nematodes in plastic tunnel houses, one of the treatments involved the inoculation of soil with P. chlamydosporia isolate IACRVc-10 (equal to our isolate 144). The extent of biocontrol by the fungus was low, and furthermore, the antagonist was reisolated at very low rates in the rhizospheres of the test plants (Verdejo-Lucas et al 2003). In the current experiments, isolate 144 was one of the most sensitive fungi in both soils.…”

Gestion des nematodes a galles parasites de la culture d’egusi par l’utilisation de <i>Trichoderma asperellum</i> et de la poudre de graine de neem

“…Cette diversité pourrait aussi affecter négativement l'efficacité des agents de lutte biologique du fait de leur sélectivité par rapport aux espèces de nématodes. Verdejo-Lucas et al (2003) ont à cet effet suggéré que la gestion durable des nématodes à galles ne pourrait être effective que grâce à une combinaison de méthodes de lutte. Des études antérieures ont démontré l'effectivité de la lutte contre les nématodes à galles lorsque les dérivés de neem sont associés à des agents biologiques comme Paecilomyces lilacinus, Pasteuria penetrans Trichoderma harzianum ou champignons mycorhiziens arbusculaires (Glomus mosseae) (Coyne et al, 2009).…”