Biological Control of the Root-Knot Nematode Meloidogyne javanica by Trichoderma harzianum

Abstract

The fungal biocontrol agent, Trichoderma harzianum, was evaluated for its potential to control the root-knot nematode Meloidogyne javanica. In greenhouse experiments, root galling was reduced and top fresh weight increased in nematode-infected tomatoes following soil pretreatment with Trichoderma peat-bran preparations. The use of a proteinase Prb1-transformed line (P-2) that contains multiple copies of this gene improved biocontrol activity in the greenhouse experiments compared with the nontransformed wild-type strain (WT). All the Trichoderma strains showed the ability to colonize M. javanica-separated eggs and second-stage juveniles (J2) in sterile in vitro assays, whereas P-2 also penetrated the egg masses. This protease-transformed line presented the same nematicidal and overall proteolytic activity as the WT in in vitro tests in which concentrated soil extracts from Trichoderma-treated soils immobilized the infective J2. However, the J2 immobilization and proteolytic activities of both P-2 and the WT were higher than those obtained with strain T-203. Characterization of the activity of all Trichoderma strains soil extracts on J2 showed that it was heat resistant and restricted to the low-molecular-weight fraction (less than 3 kDa). It is suggested that improved proteolytic activity of the antagonist may be important for the biological control of the nematodes.

Fungal root endophytes of tomato from Kenya and their nematode biocontrol potential

“…Our study is in accordance with previous experiments by others (Dababat and Sikora 2007a, b;Martinuz et al 2012b;Sikora et al 2008). With respect to reduced female fecundity, Martinuz et al (2012a) and Sharon et al (2001) also reported that fewer adult rootknot nematodes had infected tomato roots and also fewer nematodes had reached the female stage 28 days after M. incognita and M. javanica inoculation in endophytetreated plants.…”

Biological control of Meloidogyne incognita by Trichoderma harzianum and Serratia marcescens and their related enzymatic changes in tomato roots

“…The relatively high efficacy demonstrated by T. harzianum f 1 (Table 1) supports the need for further experimentations and development. Increase in the efficacy of the fungi appears possible when such biocontrol agents are integrated with organic amendments such as oil cakes (Parvatha Reddy et al, 1996) and wheat branpeat preparations (Sharon et al, 2001). Eventually, although chemical nematicide viz.…”

Evaluation of Some Botanicals and Trichoderma harzianum for the Management of Tomato Root-knot Nematode (Meloidogyne incognita (Kofoid and White) Chit Wood)

“…A reduction in root-knot development could be attributed to poor penetration of the second stage juveniles and later retardation in their activities, for example feeding and/or reproduction as suggested by Abdi [72]. Nematotoxic compounds especially the Azadirachtin released through gradual decomposition of the neem seeds [29] and suppress nematode populations throughout the whole period of the nursery stage. Nematode population in nematode + fungus treatment was 532 but L. camara has decreased population to 303.…”

“…Trichoderma viride which were reduced egg-hatching [25] and trade formulations have also proven to be efficacious in tropical greenhouse conditions [26]. Some species of Trichoderma have been used widely as bio-control agents against soil-borne plant diseases [27] and also they have activity towards root-knot nematode [28,29]. Al Kader [30] reported a high nematicidal effect of the fungus Paecilomyces lilacinus culture filtrate on J2 of M. incognita, with 99% of J2 immobilized after 2 days of treatment.…”