■ Abstract This review examines the discovery of naturally occurring phytochemicals antagonistic toward plant-parasitic and other nematodes. Higher plants have yielded a broad spectrum of active compounds, including polythienyls, isothiocyanates, glucosinolates, cyanogenic glycosides, polyacetylenes, alkaloids, lipids, terpenoids, sesquiterpenoids, diterpenoids, quassinoids, steroids, triterpenoids, simple and complex phenolics, and several other classes. Many other antinematodal compounds have been isolated from biocontrol and other fungi. Natural products active against mammalian parasites can serve as useful sources of compounds for examination of activity against plant parasites. The agricultural utilization of phytochemicals, although currently uneconomic in many situations, offers tremendous potential.

Phytochemical based strategies for nematode control.

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...

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

Increasing the productivity and product quality of vegetable crops using arbuscular mycorrhizal fungi: A review

Microalgae as multi-functional options in modern agriculture: current trends, prospects and challenges.

The filamentous fungi Trichoderma spp. is currently developed as biocontrol agents against many plant pathogens. Recent studies have shown that these fungi are able to infect nematode eggs and juveniles. In this research, biological control of root-knot nematode (Meloidogyne javanica) by Trichoderma harzianum BI was investigated in greenhouse and laboratory experiments. Results showed that different concentrations (102–108 spores/ml) of T. harzianum BI decreased nematode infection and other parameters significantly, compared to control. T. harzianum BI was able to penetrate nematode egg mass matrix and significantly decreased nematode egg hatching level. Specific activities of resistance-related enzymes, namely peroxidase (POX), polyphenol oxidase (PPO) and phenylalanine ammonia lyase (PAL) increased significantly in T. harzianum BI inoculated plants. Maximum activities of POX, PPO and PAL were observed at the 5, 5 and 6 days after inoculation, respectively. Chitinase activity was also increased in culture filtrates of T. harzianum BI grown on wheat bran moistened with salt solution supplemented with colloidal chitin or nematode eggs. Maximum activity of chitinase was recorded at the 4 days after inoculation, in media supplemented with colloidal chitin (1.15 U/min per ml) and nematode eggs (0.85 U/min per ml). Results suggested that direct parasitism of eggs through the increase in extracellular chitinase activity, which would be indicator of eggs infection capability, and inducing plant defense mechanisms leading to systemic resistance are two main suppression mechanisms used by T. harzianum BI against nematode.

Biological control of the root-knot nematode Meloidogyne javanica by Trichoderma harzianum

Aqueous extracts of neem (Azadirachta indica), castor (Ricinus communis) and pongamia (Pongamia pinnata) cakes were evaluated as substrates for mass production of the biological control agent, Trichoderma harzianum which was used in the management of Meloidogyne incognita in egg plant under fields conditions Castor cake extract at 10% gave maximum growth of mycelial mat and spore production of T harzianum compared with moderate growth in 10% pongamia cake and 5% castor cake extracts Application of plant based formulations of T harzianum to nursery beds of egg plant was effective in producing vigorous seedlings (increase in plant height and seedling weight) with the least root galling The above treatments also increased root colonization and parasitization of M incognita females by T harzianum

Evaluation of plant based formulations of trichoderma harzianum for the management of meloidogyne incognita on egg plant

Selected microbial consortia developed for chilly reduces application of chemical fertilizers by 50% under field conditions

Bacillus subtilis IIHR BS-2 enriched vermicompost controls root knot nematode and soft rot disease complex in carrot

Trichoderma harzianum in combination with neem, karanj and castor oil cakes was effective in increasing the growth of acid lime seedlings and reducing the population of Tylenchulus semipenetrans both in soil roots. The parasitization of citrus nematode females with T. harzianum increased in the presence of the oil cakes.

M. S. Rao

Papers

Evaluation of plant based formulations of trichoderma harzianum for the management of meloidogyne incognita on egg plant

Selected microbial consortia developed for chilly reduces application of chemical fertilizers by 50% under field conditions

Bacillus subtilis IIHR BS-2 enriched vermicompost controls root knot nematode and soft rot disease complex in carrot

Management of the citrus nematode, tylenchulus semipenetrans, by integration of trichoderma harzianum with oil cakes

Management of Meloidogyne incognita in tomato nurseries by integration of Glomus deserticola with Verticillium chlamydosporium