Nel biennio 2003-2004 e stata condotta un'indagine eziologica, volta a quantificare e a qualificare la presenza di miceti appartenenti al genere Fusarium in campioni di seme di riso da riproduzione prelevati presso aziende sementiere. Sono state valutate la percentuale di campioni infettati, la percentuale di seme infetto e determinate e quantificate le specie di Fusarium presenti sul seme. I dati raccolti hanno messo in evidenza che il numero di campioni infetti da Fusarium spp. e piuttosto elevato (50,5-100%), ma la percentuale di semi infetti e molto contenuta (1-5,4%). La specie isolata con maggiore frequenza e stata F. semitectum. La concia del riso da seme deve, pertanto, essere effettuata con fungicidi efficaci verso Pyricularia oryzae e Bipolaris oryzae, ma anche verso Fusarium e, in particolare, F. semitectum, data la sua crescente diffusione nel riso
Abstract Clonostachys rosea 47 (CR47), Trichoderma atroviride 59 (TA59), T. atroviride 312 (TA312), Trichoderma harzianum 24 (TH24), Trichoderma longibrachiatum 9 (TL9), T. longibrachiatum 144 (TL144) and Trichoderma viride 15 (TV15) were tested to evaluate their in vitro sensitivity towards five fungicides (carboxin, guazatine, prochloraz, thiram and triticonazole) and four herbicides (chlorsulfuron, chlorotoluron, flufenacet and pendimethalin). All antagonists showed low sensitivity to carboxin and thiram and high sensitivity to prochloraz. For mycelial radial growth, TV15 was highly sensitive to guazatine, prochloraz and triticonazole and TH24 moderately insensitive to carboxin, guazatine and thiram. For conidial germination TL144 was the most sensitive to the fungicides, for mycelial radial growth and conidial germination CR47 was the least sensitive. None of the antagonists showed any mycelial radial growth inhibition in presence of the herbicides at field dose, except for TL144. Most antagonists did not show any conidial germination inhibition by the herbicides. The in vitro toxicity of prochloraz, guazatine and triticonazole towards the antagonists was confirmed by light and scanning electron microscope showing hyphal disruptions and extrusion of cytoplasmic content. A mixture of CR47 and/or TA312 with carboxin, thiram and triticonazole, applied to wheat seeds, was able to control Fusarium culmorum artificially inoculated to wheat seedlings in growth chambers. In the field, the antagonists applied along with triticonazole or thiram, at 1/10 of the field dose to seeds naturally infected by F. culmorum , gave a disease control comparable to that induced by triticonazole at full field dose. Our results demonstrate how an integration of microorganisms with pesticides makes the control of wheat foot rot possible.
Background and Aims The present study investigated the effectiveness of bovine blood (BB)-based products, compared with that of the widely used iron ethylenediaminedi-(2-hydroxyphenylacetic) acid (Fe-EDDHA) synthetic chelate, in iron nutrition of grapevine graft combinations and rootstocks grown under different controlled conditions. Methods and Results In experiments under nutrient solution utilising rhizoboxes and pots, the effect of iron application treatments was evaluated through biometric and chlorophyll index measurements, leaf nutrient concentration and root scanning electron microscopy. Conclusions The bovine blood compounds improved iron nutrition of the grapevine similar to or better than Fe-EDDHA and enhanced root growth. Significance of the Study The experimental evidence indicates that BB-based products represent a sustainable alternative to synthetic chelates as Fe fertilisers.
