ultra high diluted arsenic reduces spore germination of alternaria brassicicola and dark leaf spot in cauliflower

ABSTRACT A major problem in cauliflower crop is the fungus Alternaria brassicicola, which causes dark leaf spot on Brassicaceae family. The current use of copper salts in agriculture is questioned. In fact, these products present some disadvantages, connected mainly with their deposits in the soil and toxicity on plants. This work investigated the effects of arsenic treatments, in ultra high diluted form (UHD), prepared by a process of repeated dilution and succussion (shaking), through: 1) in vitro germination experiments, where spores of A. brassicicola were suspended in the treatments; 2) in planta experiments and 3) a field trial, where cauliflower plants infected by the fungus were sprayed with treatments. The results showed that ultra high dilutions of arsenic (where no more molecules of this substance are present) were effective in all the experiments, inhibiting spore germination by 60.0%, controlling fungal disease in in planta experiments (relative efficacy of 42.1%), and, in field trial, decreasing the mean infection level in cauliflower heads by 45.7% and 41.6% in artificially inoculated and naturally infected plants, respectively. This is the first study to demonstrate that ultra high dilutions effectively reduce in vitro spore germination and infection of A. brassicicola in cauliflower plants, both under controlled conditions and in the field. Our research is still very experimental, however, in light of the significant results obtained with ultra-diluted arsenic, and given that its extreme high dilution level precludes any toxicity or accumulation in the environment, the use of UHDs could be considered a potential and reliable approach for sustainable agriculture

Survey of the main causal agents of fusarium head blight of durum wheat around Bologna, northern Italy

Several Fusarium species and Microdochium nivale are involved in fusarium head blight (FHB), which in Italy has been constantly present on wheat since 1995. This study was carried out from 1995 to 2007 on FHB-infected durum wheat heads collected in the Bologna countryside, Emilia-Romagna, northern Italy. The most frequent Fusarium species found were: Fusarium graminearum (32.1%), F. culmorum (25.2%) and F. poae (17.8%), while F. avenaceum and M. nivale occurred discontinuously. Other Fusarium species were also found, but only sporadically. It is important to identify and characterize the main species involved in the FHB syndrome for this will help us to establish control strategies that will contain the disease and the content of mycotoxins in food and animal feed

Ultra high diluted arsenic reduces spore germination of Alternaria brassicicola and dark leaf spot in cauliflower

ABSTRACT A major problem in cauliflower crop is the fungus Alternaria brassicicola, which causes dark leaf spot on Brassicaceae family. The current use of copper salts in agriculture is questioned. In fact, these products present some disadvantages, connected mainly with their deposits in the soil and toxicity on plants. This work investigated the effects of arsenic treatments, in ultra high diluted form (UHD), prepared by a process of repeated dilution and succussion (shaking), through: 1) in vitro germination experiments, where spores of A. brassicicola were suspended in the treatments; 2) in planta experiments and 3) a field trial, where cauliflower plants infected by the fungus were sprayed with treatments. The results showed that ultra high dilutions of arsenic (where no more molecules of this substance are present) were effective in all the experiments, inhibiting spore germination by 60.0%, controlling fungal disease in in planta experiments (relative efficacy of 42.1%), and, in field trial, decreasing the mean infection level in cauliflower heads by 45.7% and 41.6% in artificially inoculated and naturally infected plants, respectively. This is the first study to demonstrate that ultra high dilutions effectively reduce in vitro spore germination and infection of A. brassicicola in cauliflower plants, both under controlled conditions and in the field. Our research is still very experimental, however, in light of the significant results obtained with ultra-diluted arsenic, and given that its extreme high dilution level precludes any toxicity or accumulation in the environment, the use of UHDs could be considered a potential and reliable approach for sustainable agriculture

First report of Neofusicoccum parvum causing stem and branch canker on Cannabis sativa in Italy

In 2016, symptoms of stem canker with branches dieback were detected in several Cannabis sativa L. crops, located in the northeast part of Italy (Rovigo district). Morphological and molecular identifications of the fungal colonies isolated revealed the presence of Neofusicoccum parvum. The pathogenicity was verified with Koch\u2019s postulates setup. To our knowledge, this is the first report of N. parvum as a pathogen of C. sativa worldwide

Phytormones in kiwifruit plants affected by elephantisis.

Since 2001 an unusual disease, named elephantiasis, was observed in the kiwifruit cultivar ‘Hayward’ in orchards of Northern Italy. The symptom typical of elephantiasis in kiwifruit is trunk hypertrophy, at which a marked brown discoloration of the annual rings is associated. Fungi isolated from necrotic sections of plants are belonging to different fungal genera such as Fusarium spp. - mainly F. solani, Cylindrocarpon spp. and Phialophora-like, that include Phaeoacremonium, Cadophora, Lecythophora. The kiwifruit plant tissue colonization capacity of P. aleophilum, Cadophora melinii and F. solani was verified, while pathogenicity trials using these fungi are in progress in an experimental field. To explain the trunk hypertrophy, trunks of diseased and asymptomatic plants coming from the same orchard were analyzed for the presence of hormones by HPLC-ESi-MS/MS. The hormones analyzed were abscisic acid (ABA), iasmonic acid (JA), salicylic acids (SA), indolacetic acid (IAA) and Gibberellins (GA1, GA3, GA4, GA34). The presence of these hormones showed a similar trend in the majority of the samples either from diseased and asymptomatic plants, except GA34 that it was present exclusively in diseased plants. Gibberellins (GAs) are a large family of hormones that can regulate germination, elongation growth and sex determination. GAs products by fungi are known to induce abnormal tissue growth. These results induce us to further investigate the possible direct production of Gibberellins by the fungi associated to this unusual disease and their involvement in the trunk hypertrophy

Aggressiveness of different Fusarium graminearum chemotypes within a population from Northern-Central Italy

The aggressiveness of 32 Fusarium graminearum strains isolated from durum wheat cultivated in Northern-Central Italy was assessed. The chemotype (15-acetyldeoxynivalenol-, 3-acetyldeoxynivalenol- or nivalenol-producer) of each strain was characterized with multiplex PCR. Two aggressiveness assays (single floret inoculation and the Petri-dish test), which yielded three aggressiveness indices, were used. One strain from southern Italy (moderately aggressive) was added as the positive control to evaluate the accuracy of the aggressiveness quantification in both assays. The results showed that all 32 F. graminearum strains are pathogenic and a wide range of aggressiveness levels was observed. The positive control strain is pathogenic and showed moderately aggressive in both assays, thus indicated that our aggressiveness quantifications are valid. Six highly aggressive strains, representing all three chemotypes, were stable in the different aggressiveness assays. There was no significant difference in aggressiveness among the three different chemotypes (P = 0.909-0.972) determined by three aggressiveness indices. Highly significant correlations of AUDPCstandard to mean and terminal disease severity (r = 0.91, P < 0.001 in both cases) reveal the potential of using the Petri-dish test for selection of F. graminearum inocula with the proper and/or varying aggressiveness levels for breeding purposes. \ua9 2013 The Mycological Society of Japan

Detection of Fumonisins in Fresh and Dehydrated Commercial Garlic

An epidemic fungal disease caused by Fusarium proliferatum, responsible for fumonisin production (FB1, FB2, and FB3), has been reported in the main garlic-producing countries in recent years. Fumonisins are a group of structurally related toxic metabolites produced by this pathogen. The aim of this work was to establish an enzyme-linked immunosorbent assay (ELISA) procedure, mostly applied to cereals, that is suitable for fumonisin detection in garlic and compare these results to those obtained by high-performance liquid chromatography (HPLC) and screening of fresh and dehydrated garlic for toxicological risk. The results show good correlation between the two analytical methods. In fresh symptomatic garlic, fumonisin levels were higher in the basal plates than those in the portions with necrotic spots. Among the 56 commercially dehydrated garlic samples screened, three were positive by ELISA test and only one was above the limit of quantitation. The same samples analyzed by HPLC showed the presence of FB1 in trace amounts that was below the limit of quantitation; FB2 and FB3 were absent. The results are reassuring, because no substantial contamination by fumonisins was found in commercial garlic