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Encapsulation of Trichoderma harzianum Rifai in sodium alginate pellets

Topolovec-Pintarić S.*, Miličević T., Džidić A., Cvjetković B.,

Faculty of Agriculture, Dept of Plant Pathology, Zagreb, Croatia

The introduction of antagonistic fungi into the soil as biocontrol agents (BCA) against phytopathogenic soil borne fungi is often difficult. The introduced antagonistic fungi must adjust to the environment and survive. Initially, it must compete with harmful microbes for the occupation  of the rhizosphere,  trying to colonize the available sites along the plant roots and prevent pathogens from making contact with the root tissue. Therefore, BCAs that use competition to suppress disease generally need to be applied in high densities before the pathogen is present. The development of effective, low-cost fungal inocula engineered to maintain inoculum potential during transport, storage and application, is one of the keys to the commercialisation of the fungal soil remediation. Most of the examples on different types of fungal inocula carriers for biological control include peat, granular vermiculite or clay mixtures, grains and alginate pellets. The objectives of this work were to determine the possibility of dispersal of an isolate of Trichoderma harzianum (TKP) in the soil in the form of sodium alginate pellets, and to determine the effects of the isolate TKP on the germination of the pelleted flax seed (seed coated with spore suspension of the isolate TKP and sodium alginate).

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EFFICACY OF FUNGICIDES in Yeast Based ENCAPSULATion formulations

Craig Duckham*, Marie Guingouain & Steve Rossall

*Micap plc. Lodge Lane, Newton-Le-Willows, WA12 0JQ UK.Plant Sciences Division, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD UK.

Micap plc has a patented technique for encapsulating active ingredients within micro-organisms. The technology has been developed primarily using yeast cells (Saccharomyces cerevisiae) as an adjuvant (excipient or carrier in drug and flavour delivery applications), although other fungi and bacteria are amenable. Initial successes were achieved in the flavour and fragrance industry protecting volatile components during processing but now trials are underway to demonstrate the principle of using the technology to deliver pesticides effectively in crop protection applications.Where disease control, provided by existing technology, is inadequate encapsulation can provide a means of delivering fungicides efficiently in crop protection applications and give opportunities for novel formulations. Microencapsulation may offer the prospect of reduced application rates where efficacy is improved and have an added attraction where environmental and food-residue advantages may be delivered. The target of this current study is the fusarium pathogens responsible for stem-based cereal diseases including Fusarium Ear (Head) Blight. The aim of the investigation was to evaluate Micaptm formulations of tebuconazole against Fusarium (F. culmorum) infection of wheat. Control of both the stem-base infection and ear blight stage of the disease were assessed. In both cases, products which remain localised to the site of infection should have an advantage over conventional products. Data are presented which demonstrate that Micaptm encapsulated tebuconazole is active in vitro and is more effective than a commercial formulation (Folicur) at treating stem and ear blight stages of Fusarium infection.  Ear blight control demonstrated both an increase in thousand grain weight and decreased accumulation of the mycotoxin deoxynivalenol (DON). DON concentrations were up to 5 fold lower in grain following treatment with Micaptm encapsulated tebuconazole compared with Folicur applied at the same rate.  On-going work will provide more data on the activity of Micaptm formulations of triazoles against Fusarium and Septoria diseases of wheat.

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ESSENTIAL OILS AS POTENTIAL BACTERICIDES IN PLANT PROTECTION

N. S. IACOBELLIS and P. LO CANTORE

Dipartimento di Biologia, Difesa e Biotecnologie Agro Forestali, Università degli Studi della Basilicata, Viale dell’Ateneo Lucano 10, 85100 Potenza, Italy

The control of bacterial diseases of plants, which may be destructive under certain environmental conditions, is a considerable problem in the agriculture practice because of the limited availability of bactericides. Only a few chemical products are available on the market and often their use is hampered by the limited efficacy in the field and mainly for their potential negative effect either on the environment or on the human and animal health. The actual limitation of the use of antibiotics in plant protection is based on the possibility to select the pathogen population resistant to the substances of interest and the consequent potential transfer of the above character to animal and human pathogenic bacteria. Although the matter is still object of debate as a matter of the fact  the use of antibiotics is forbidden in many European Countries. Only in USA and a few other Countries oxytetracycline and streptomycin are used to control highly dangerous bacterial diseases on important crops. Also the use of copper compounds, so far the only bactericide widely used for the control of plant bacterial diseases, will be limited for their impact on the environment in the European union Countries by the rule n° 473/2002. As a consequence the measures to control plant bacterial diseases are mostly limited to preventive ones including the use of healthy propagation material (i.e. seeds, etc.,). The availability of new and eco-compatible bactericides may be very useful for plant protection by diseases caused by bacteria. Many studies have pointed out on the possibility to use essential oils and/or their components in medical pathology as well as in the food industry for the control of bacteria and fungi pathogenic to consumers and/or responsible for food spoilage. Hence, essential oils appear as good candidates for the control of plant diseases and, in particular, those caused by bacteria. With the above aim essential oils extracted from fruits of caraway, coriander, cumin and fennel, were assayed in vitro for antibacterial activity toward two laboratory and 29 phytopathogenic bacterial species as well as responsible of cultivated mushrooms diseases. Significant antibacterial activity was shown by essential oils of caraway, coriander, cumin against gram positive and  Gram negative bacteria

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