The Botryosphaeriaceae: genera and species known from culture

The Colletotrichum acutatum species complex

In vitro antagonism of Trichoderma species against six fungal plant pathogens [Biological disease control]

Since the initial use of Bordeaux mixture in 1885 for plant disease control, a large number of copper-based antimicrobial compounds (CBACs) have been developed and applied for crop protection. While these compounds have revolutionized crop protection in the twentieth century, their continuous and frequent use has also raised concerns about the long-term sustainability of copper (Cu)-based crop protection system. Here, we review CBACs used in crop protection and highlight their benefits and risks, and potential for their improvement and opportunities for further research to develop alternatives to CBACs. The major findings are (i) the relatively high toxicity to plant pathogens, low cost, low mammalian toxicity of the fixed Cu compounds, and their chemical stability and prolonged residual effects are major benefits of these compounds; (ii) phytotoxicity, development of copper-resistant strains, soil accumulation, and negative effects on soil biota as well as on food quality parameters are key disadvantages of CBACs; (iii) regulatory pressure in agriculture worldwide to limit the use of CBACs has led to several restrictions, including that imposed by the regulation 473/2002 in the European Union; and (iv) mitigation strategies to limit the negative effects of CBACs include their optimized use, soil remediation, and development and application of alternatives to CBACs for a sustainable crop protection. We conclude that recent research and policy efforts have led to the development of a number of alternatives to CBACs, which should be further intensified to ensure that growers have sufficient tools for the implementation of sustainable crop protection strategies.

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Thirteen decades of antimicrobial copper compounds applied in agriculture. A review

Whether modern agriculture without conventional pesticides will be possible or not is a matter of debate. The debate is meaningful within the context of rising health and environmental awareness on one hand, and the global challenge of feeding a steadily growing human population on the other. Conventional pesticide use has come under pressure in many countries, and some European Union (EU) Member States have adopted policies for risk reduction following Directive 2009/128/EC, the sustainable use of pesticides. Highly diverse crop production systems across Europe, having varied geographic and climatic conditions, increase the complexity of European crop protection. The economic competitiveness of European agriculture is challenged by the current legislation, which banned the use of many previously authorized pesticides that are still available and applied in other parts of the world. This challenge could place EU agricultural production at a disadvantage, so EU farmers are seeking help from the research community to foster and support integrated pest management (IPM). Ensuring stable crop yields and quality while reducing the reliance on pesticides is a challenge facing the farming community is today. Considering this, we focus on several diverse situations in European agriculture in general and in European crop protection in particular. We emphasize that the marked biophysical and socio-economic differences across Europe have led to a situation where a meaningful reduction in pesticide use can hardly be achieved. Nevertheless, improvements and/or adoption of the knowledge and technologies of IPM can still achieve large gains in pesticide reduction. In this overview, the current pest problems and their integrated management are discussed in the context of specific geographic regions of Europe, with a particular emphasis on reduced pesticide use. We conclude that there are opportunities for reduction in many parts of Europe without significant losses in crop yields.

https://apsjournals.apsnet.org/doi/pdf/10.1094/PDIS-05-15-0574-FE

Toward a Reduced Reliance on Conventional Pesticides in European Agriculture

Branch cankers and stem-end rot are two of the most important threats to avocado production. During the autumn of 2013, sampling was conducted in the main avocado growing area in eastern Sicily to study the occurrence and establish the causal agents of branch canker and stem-end rot. A total of 94 fungal isolates, recovered from four avocado orchards, were identified by morphological characterisation, DNA sequencing and phylogenetic analyses as belonging to the genera Colletotrichum, Neofusicoccum or Diaporthe. The majority of the isolates were identified as Neofusicoccum parvum (70.2 %), with the remaining isolates being Colletotrichum gloeosporioides or C. fructicola (16 %), and Diaporthe foeniculacea or D. sterilis (13.8 %), respectively. Pathogenicity tests showed N. parvum was the most virulent species (P = 0.05), whereas Diaporthe isolates were the least so. An intermediate virulence was observed for C. gloeosporioides and C. fructicola, which were associated only with stem-end rot of fruit. Regarding cultivar susceptibility of fruit to these pathogens, ‘Hass’ was more susceptible to infection by C. fructicola and D. foeniculacea compared with ‘Bacon’ whereas no significant differences were detected for the remaining pathogens. To our knowledge, this is the first account of the pathogens causing branch canker and stem-end rot of avocado in Italy, and the first studies comparing the relative virulence of each species involved.

Characterisation and pathogenicity of fungal species associated with branch cankers and stem-end rot of avocado in Italy

Postharvest biocontrol ability of Pseudomonas synxantha against Monilinia fructicola and Monilinia fructigena on stone fruit

During the 2009 and the 2010 growing seasons, a root rot disease has been detected on young potted Persea americana plants in two nurseries located in the Catania and Messina provinces (eastern Sicily, Italy). A Cylindrocarpon sp. was consistently recovered from pieces of symptomatic tissues on Petri dishes containing potato dextrose agar. On the basis of morphological characteristics and molecular identification by DNA sequencing and phylogenetic analysis of internal transcribed spacer and b-tubulin gene regions, the causal agent was identified as Ilyonectria (=Neonectria) macrodidyma. Kochs postulates were fulfilled by pathogenicity tests carried out on potted P. americana seedlings. To our knowledge, this is the first to report worldwide of the occurrence of a disease caused by I. macrodidyma on P. americana.

First Report of Root Rot Caused by Ilyonectria (=Neonectria) macrodidyma on Avocado (Persea americana) in Italy

During the period from 2010 to 2013 preharvest symptoms were detected on different cultivars of sweet orange in six orchards in Catania, Siracusa and Enna provinces, Southern Italy A total of 56 monosporic fungal isolates were obtained, and among these, 44 were identified as Colletotrichum gloeosporioides and 12 as C karstii through morphological and molecular analysis PCR with primers ITS1 and ITS4, primers TubGF1 and TubGR specific for β-tubulin gene, primers GDF-GDR, specific for Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene, were used to confirm the identification of Colletotrichum isolates from citrus The ITS1-58S-ITS2 region, a portion of approximately 500 bp of β-tubulin gene and a fragment of 220 bp of GAPDH gene of the isolates were sequenced and analysed with the BLASTn program Koch's postulates were fulfilled by pathogenicity tests carried out on fruit of ‘Tarocco Scire’ and ‘Tarocco Nucellare’ with representative isolates of C gloeosporioides and C karstii Field surveys and pathogenicity tests revealed significant differences in fruit susceptibility between ‘Tarocco Scire’ and ‘Tarocco Nucellare’ and in virulence between the fungal species To our knowledge, this is the first report on the emergence of Colletotrichum spp causing anthracnose in preharvest conditions

Characterization and Pathogenicity of Colletotrichum gloeosporioides and C. karstii Causing Preharvest Disease on Citrus sinensis in Italy

The objective of this research was to evaluate Trichoderma harzianum strain T22 as a biocontrol agent of collar and root rot caused by different Calonectria pauciramosa isolates. Thus, the microsclerotia-forming ability and virulence of twenty C. pauciramosa isolates were assessed. Microsclerotia production varied partially among the isolates and dual culture with T22 on carnation leaf agar revealed isolates with both high and low microsclerotia-forming ability. Inoculation tests on red clover (Triflolium pratense) demonstrated its susceptibility to the pathogen. On red clover, the degree of virulence and T22 effects in controlling infections were highly variable among the isolates tested. A nursery trial performed on Feijoa sellowiana seedlings confirmed previous results, clearly indicating virulence variability among C. pauciramosa isolates. For three isolates tested in nursery trial, T22 effectiveness in controlling infection was inversely related to their degree of virulence. Overall, T. harzianum strain T22 showed good antagonist activity in reducing microsclerotia production on carnation leaf and the incidence and severity of collar and root rot on both selected hosts. This data could be crucial in developing integrated pest management strategies in ornamental plant nurseries.

Dalia Aiello

Papers

Characterisation and pathogenicity of fungal species associated with branch cankers and stem-end rot of avocado in Italy

Postharvest biocontrol ability of Pseudomonas synxantha against Monilinia fructicola and Monilinia fructigena on stone fruit

First Report of Root Rot Caused by Ilyonectria (=Neonectria) macrodidyma on Avocado (Persea americana) in Italy

Characterization and Pathogenicity of Colletotrichum gloeosporioides and C. karstii Causing Preharvest Disease on Citrus sinensis in Italy

Evaluation of Trichoderma harzianum strain T22 as biological control agent of Calonectria pauciramosa