Update of pistachio leaf spot caused by Septoria pistaciarum in light of new taxonomic advances in Italy.

Abstract Septoria leaf spot is one the most widespread disease affecting pistachio (Pistacia vera) in countries of the Mediterranean region. Traditionally, three species have been associated with pistachio, including Septoria pistaciae, Septoria pistaciarum and S. pistacina. However, recent taxonomic studies have reordered and clarified the status of Septoria and septoria-like pathogens affecting pistachio. In our study, field surveys conducted in the traditional Sicilian pistachio production area of Bronte revealed the presence of trees showing characteristic septoria-like leaf spot. Collected isolates were morphologically and molecularly characterized. Morphological characterization was based on conidia measurements and evaluation of mycelial growth on different artificial media. Tested media included CMA, MEA, OA, PDA, and SNA. Phylogenetic analysis was conducted on a multi-locus approach (ITS + tef1 + tub2) based on Maximum Parsimony and Maximum Likelihood. Results showed that our isolates clustered with S. pistaciarum. Pathogenicity test was conducted in the field using conidia suspensions in order to fulfill Koch's postulates. Presence of characteristic rounded spots and pycnidia was evaluated on the inoculated leaves 9 and 23 days after inoculation. This study represents the first update on S. pistaciarum in Italy since its first identification in 1934

Further Investigation on Limb Dieback of Fig (Ficus carica) Caused by Neoscytalidium dimidiatum in California.

Fig limb dieback is a cosmopolitan disease caused by Neoscytalidium dimidiatum (Botryosphaeriaceae), characterized by branch and shoot cankers, discoloration of woody tissues, and dieback. The present study investigated the etiology of the disease in California that seems to have become prevalent among fig orchards in the last several years. During orchard surveys in Fresno, Kern, and Madera Counties over 3 years, we isolated consistently and evaluated the pathogenicity of N. dimidiatum under laboratory and field conditions. The effect of summer and winter pruning on the disease severity and the effects of different environmental and mechanical stresses, such as sunburn and wounding by mallets, were assayed. In addition, the susceptibility of six different cultivars and the effects of eradicating cankered shoots from the fig trees as a method to combat the spread of the disease were studied. Pathogenicity tests demonstrated that N. dimidiatum induces cankers on fig, mainly on wounded shoots. Results from the remaining experiments revealed that summer infection leads to more severe canker lesions than those induced by winter infection and that stressed shoots are more susceptible to infection than nonstressed shoots. 'Brown Turkey', 'Conadria', and 'Calimyrna' cultivars (all nonpersistent figs, i.e., needing pollination for fruit development) were less susceptible than the more susceptible 'Kadota', 'Sierra', and 'Black Mission' (all persistent figs, i.e., not needing pollination for fruit development). Canker removal from the orchard seems to be a good agronomic practice to avoid the spread of disease

Present status and perspective on the future use of aflatoxin biocontrol products

Aflatoxin contamination of important food and feed crops occurs frequently in warm tropical and subtropical regions. The contamination is caused mainly by Aspergillus flavus and A. parasiticus. Aflatoxin contamination negatively affects health and trade sectors and causes economic losses to agricultural industries. Many pre- and post-harvest technologies can limit aflatoxin contamination but may not always reduce aflatoxin concentrations below tolerance thresholds. However, the use of atoxigenic (non-toxin producing) isolates of A. flavus to competitively displace aflatoxin producers is a practical strategy that effectively limits aflatoxin contamination in crops from field to plate. Biocontrol products formulated with atoxigenic isolates as active ingredients have been registered for use in the US, several African nations, and one such product is in final stages of registration in Italy. Many other nations are seeking to develop biocontrol products to protect their crops. In this review article we present an overview of the biocontrol technology, explain the basis to select atoxigenic isolates as active ingredients, describe how formulations are developed and tested, and describe how a biocontrol product is used commercially. Future perspectives on formulations of aflatoxin biocontrol products, along with other important topics related to the aflatoxin biocontrol technology are also discussed.Fil: Moral, Juan. Universidad de Córdoba; EspañaFil: Garcia-Lopez, Maria Teresa. Universidad de Córdoba; EspañaFil: Camiletti, Boris Xavier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias. Departamento de Recursos Naturales. Cátedra de Microbiología Agrícola; ArgentinaFil: Jaime, Ramon. University of California at Davis; Estados UnidosFil: Michailides, Themis J.. University of California at Davis; Estados UnidosFil: Bandyopadhyay, Ranajit. International Institute of Tropical Agriculture; NigeriaFil: Ortega-Beltran, Alejandro. International Institute of Tropical Agriculture; Nigeri

Effect of Cultivar Resistance and Soil Management on Spatial–Temporal Development of Verticillium Wilt of Olive: A Long-Term Study

Verticillium wilt, caused by Verticillium dahliae, challenges olive cultivation and an Integrated Disease Management (IDM) approach is the best-suited tool to combat it. Since 1998, an IDM strategy in an orchard (called Granon, Spain) of the susceptible cv. Picual was conducted by increasing planting density with moderately resistant cv. Frantoio, chemical weed control, and replanting of dead olives with cv. Frantoio following soil solarization. The Verticillium wilt epidemic in Granon orchard was compared to the epidemic in a non-IDM orchard (called Ancla, Spain) with plowed soil and dead Picual olives replanted with the same cultivar. Field evaluations (2012–2013) showed an incidence and severity of the disease as Picual–Ancla > Picual–Granon > Frantoio–Granon. The spatiotemporal dynamics of the Verticillium epidemics from 1998 to 2010 were monitored with digital images using SIG. The annual tree mortalities were 5.6% for Picual olives in Ancla orchard, and 3.1 and 0.7% for Picual and Frantoio olives in Granon orchard, respectively. There was a negative relationship between the mortality of olive trees (%) by the pathogen and the height (m) above sea level. The annual mortality of cv. Picual olives was positively correlated with spring rainfalls. The Index of Dispersion and beta-binomial distribution showed aggregation of Verticillium-dead olives. In conclusion, this IDM strategy considerably reduced the disease in comparison with traditional agronomic practices

Characterization of Argentinian Endemic Aspergillus flavus Isolates and Their Potential Use as Biocontrol Agents for Mycotoxins in Maize

Maize (Zea mays L.) is a highly valuable crop in Argentina, frequently contaminated with the mycotoxins produced by Aspergillus flavus. Biocontrol products formulated with atoxigenic (nontoxic) strains of this fungal species are well known as an effective method to reduce this contamination. In the present study, 83 A. flavus isolates from two maize regions of Argentina were characterized and evaluated for their ability to produce or lack of producing mycotoxins in order to select atoxigenic strains to be used as potential biocontrol agents (BCA). All of the isolates were tested for aflatoxin and cyclopiazonic acid (CPA) production in maize kernels and a liquid culture medium. Genetic diversity of the nonaflatoxigenic isolates was evaluated by analysis of vegetative compatibility groups (VCG) and confirmation of deletions in the aflatoxin biosynthesis cluster. Eight atoxigenic isolates were compared for their ability to reduce aflatoxin and CPA contamination in maize kernels in coinoculation tests. The A. flavus population was composed of 32% aflatoxin and CPA producers and 52% CPA producers, and 16% was determined as atoxigenic. All of the aflatoxin producer isolates also produced CPA. Aflatoxin and CPA production was significantly higher in maize kernels than in liquid medium. The 57 nonaflatoxigenic strains formed six VCG, with AM1 and AM5 being the dominant groups, with a frequency of 58 and 35%, respectively. In coinoculation experiments, all of the atoxigenic strains reduced aflatoxin from 54 to 83% and CPA from 60 to 97%. Members of group AM1 showed a greater aflatoxin reduction than members of AM5 (72 versus 66%) but no differences were detected in CPA production. Here, we described for the first time atoxigenic isolates of A. flavus that show promise to be used as BCA in maize crops in Argentina. This innovating biological control approach should be considered, developed further, and used by the maize industry to preserve the quality properties and food safety of maize kernels in Argentina.Instituto de Patología VegetalFil: Camiletti, B.X. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Camiletti, B.X. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; ArgentinaFil: Moral, Juan. University of Córdoba. Campus de Rabanales. Departamento de Agronomía; EspañaFil: Moral, Juan. University of California. Kearney Agricultural Research and Extension Center; Estados UnidosFil: Asensio, Claudia M. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias. Química Biológica; ArgentinaFil: Asensio, Claudia M. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Torrico Ramallo, Ada Karina. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Lucini, Enrique I. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias. Microbiología Agrícola; ArgentinaFil: Gimenez, Maria De La Paz. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Michailides, Themis J. University of California. Kearney Agricultural Research and Extension Center; Estados Unido

Harvesting and handling effects on postharvest decay

Purpose of review: The aims of this review are: (1) to highlight the most significant results over the last few years in harvesting methods and pre- and postharvest handling of horticultural products; and (2) to provide insights in terms of technological aspects, with special reference to the control of postharvest decay. New system approaches that should be considered as components of an integrated decay control strategy and overall good agricultural practices are also described. Main findings: Harvest and handling practices have major effects on postharvest decay. Mechanical harvesting systems and time of harvest have a prominent effect on postharvest decay and mycotoxin contamination. Fruit maturity at harvest, which directly affects bruising, is a major factor affecting infection by postharvest pathogens. Harvest of fruits from the ground and contact of harvest containers with soil contaminate fruits with postharvest propagules and result in increased decay. Climatic conditions affect sources of contamination and infection of fruits: under dry, hot subtropical climates latent and quiescent infections preharvest play a significant role while under warm, humid tropical climates contamination of fruit wounds during harvest can be of great importance, affecting levels of postharvest decay. Packing directly in the field reduces production costs but increases chances for postharvest decay. Electronic noses have been constructed that can "smell" and separate decayed fruits in packinghouses and predict mycotoxin contamination. Regression models have been developed to detect the impact of mechanical damage on postharvest decay. In addition, new packaging systems have been created to minimise mechanical injuries and decrease susceptibility to decay and bruising. Postharvest treatments, such as application of reduced-risk fungicide, biological agents and natural products, heat treatment and edible coating formulations, alone or in combination, can be successfully applied in a range of commodities in order to prevent decay. Directions for future research: The mode of action of antagonistic yeast in postharvest fruit disease control may be an important tool in postharvest biocontrol strategies, thus providing important guidance for their future application. In addition, mixtures of low-risk fungicides with biological agents should be carried out to identify the best postharvest treatments with the lowest environmental impact and the greatest consumer safety. Comparative studies for a range of fleshy products harvested from organic, integrated and conventional production systems should be also carried ou