Biological Alternatives
Among the biological alternatives one may find the use of agents, such as Trichoderma and Paecylomices among others.
Trichoderma are fungi present in nearly all soils. They frequently are the most prevalent fungi. Trichoderma is able to parasitize plant pathogens as Pythium and Rhizoctonia the surface of pea seed. Some Trichoderma strains are able to colonize and grow on roots as they develop. Once they come into contact with roots, they colonize the root surface. If this agent is used for seed treatment, it will probably colonize roots deeply in soil. The other characteristic is that the strains persist for long time in soil.
The other advantage of using Trichoderma is that it increases plant growth and development, and promote the emission of stronger roots.
Trichoderma can be drenched in soil, and in that way it provides good protection to crop against various fungi.
In Naivasha, Kenya, Trichoderma applied twice at 40 g / 10 litres of water in carnation, the first application at planting and the second four weeks later, combined with biofumigation, gave excellent results even better than the plots fumigated with methyl bromide. This alternative is very much accepted in that area of Kenya.
Paecilomyces is a filamentous fungus which is found in soil, and in decaying plants. Some species of Paecilomyces may also be isolated from insects. The most common species of this genus are Paecilomyces lilacinus and Paecilomyces variotii.
Several Paecilomyces can cause various infections in humans, such as the so-called paecilomycosis, corneal ulcer, keratitis, and endophthalmitis. For this reason any product or formulation based on any of these fungi should be handled with care.
The strain 251 of Paecilomyces lilacinus is a naturally occurring fungus, which is quite effective against nematodes that attack plant roots. The fungus showed no toxicity or pathogenicity when tested in rodents and various invertebrates, and this strain does not survive at human body temperature. It is effective against root nematodes, such as root knot nematodes (Meloidogyne spp.) and cyst nematodes (Heterodera spp. and Globodera spp.).
Paecilomyces exerts a mechanical and enzimatic action inside nematode eggs, where it produces several enzymes able to penetrate the eggs. The mycelia of the fungus develop well inside the egg releasing spores able to parasitize new eggs. The spores, at the same time, can also fix to the cuticle of nematodes, germinating there while the mycelium again penetrates the cuticle of the nematode. The fungus takes whatever it requires from its life from the nematode body causing finally its death.
Paecilomyces is normally applied diluted with water to the soil either pre-planting or during the crop cycle at intervals of 4- 6 weeks.
All these agents are appropriate for their use in organic farming production.
