RESUMEN
BACKGROUND: Sclerotinia sclerotiorum (Lib.) de Bary is a major pathogen of witloof chicory. For lack of authorised field treatment, post-harvest sprays with dicarboximide fungicides have been standard practice since the 1970s to prevent root rot and chicory heart decay during the forcing phase. However, the registration of procymidone and vinclozolin has been withdrawn in Europe. The development of organic agriculture and the necessity to reduce fungicide applications in conventional agriculture prompted an assessment of the efficacy of new fungicides and the use of the mycoparasite Coniothyrium minitans (Campbell). RESULTS: A mixture of the fungicides fludioxonil and cyprodinil (Switch(®) ) applied on chicory roots achieved a very good control of S. sclerotiorum (up to 95%). The use of C. minitans limited root infection, both when applied in the field (50-65% efficacy) and before the forcing period (post-harvest treatment up to 80%). CONCLUSION: In organic agriculture, two treatments with C. minitans (in field and later at the forcing period) could improve protection against S. sclerotiorum. In conventional agriculture, after the field biological treatment, a post-harvest chemical treatment could be applied. The addition of other prophylactic methods could lead to a high level of performance in practice against decay caused by S. sclerotiorum.
Asunto(s)
Antibiosis , Ascomicetos/efectos de los fármacos , Ascomicetos/fisiología , Cichorium intybus/microbiología , Fungicidas Industriales/farmacología , Enfermedades de las Plantas/microbiología , Cichorium intybus/crecimiento & desarrollo , Agricultura Orgánica , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/microbiologíaRESUMEN
The activity of eugenol oil was evaluated in vitro and in vivo against four apple pathogens namely Phlyctema vagabunda, Penicillium expansum, Botrytis cinerea and Monilinia fructigena. The minimum inhibitory concentration (MIC) of eugenol incorporated in malt extract agar medium was found to be 2 mg ml(-1). Mycelial growth of the four test pathogens was completely inhibited when treated with 150 microl l(-1) of volatile eugenol whether at 4 or 20 degrees C. Conidia of P. vagabunda, P. expansum, M. fructigena and B. cinerea suspended for 2 min in eugenol solution at 2 mg ml(-1) heated to 50 degrees C germinated at rates of 19, 37, 38 and 39%, respectively. Three different eugenol formulations (Tween 80, ethoxylate and lecithin) were tested for their in vivo efficacy against the tested pathogens on apples. Ethoxylate- and Tween 80-eugenol formulations applied at room temperature were ineffective in reducing disease incidence. When heated to 50 degrees C, both formulations induced phytotoxicity on apple surface and caused cuticle damages as revealed by scanning electronic microscopic observations. A mixture of eugenol at 2 mg ml(-1) and soy lecithin at 50 mg ml(-1) suppressed the phytotoxic symptoms produced by eugenol on apples and reduced the disease incidence of P. expansum, P. vagabunda, B. cinerea and M. fructigena to less than 7, 6, 4 and 2% respectively after 6 months of storage at 2 degrees C. The application of heated lecithin-formulated eugenol could become a successful alternative to the traditional fungicides used in postharvest disease management of apple fruit.