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Botrytis cinerea, Rhizoctonia solani and Hemileia vastatrix are three species of phytopathogenic fungi behind major crop losses worldwide. These have been selected as target models for testing the fungicide potential of a series of bis(ylidene) cyclohexanones. Although some compounds of this chemical class are known to have inhibitory activity against human pathogens, they have never been explored for the control of phytopathogens until now. In the present work, bis(ylidene) cyclohexanones were synthesized through simple, fast and low-cost base- or acid-catalyzed aldol condensation reaction and tested in vitro against B. cinerea, R. solani and H. vastatrix. bis(pyridylmethylene) cyclohexanones showed the highest activity against the target fungi. When tested at 200 nmol per mycelial plug against R. solani., these compounds completely inhibited the mycelial growth, and the most active bis(pyridylmethylene) cyclohexanone compound had an IC

The initial objective of our work was to synthesize a series of 2-amino-4H-pyran-3-carbonitriles to be tested for their antifungal activities against economically relevant phytopathogenic fungi. Fourteen compounds were prepared in up to 94% yield and shown percentages of Botrytis cinerea inhibition above 70%. Despite the promising biological results, we observed that stock solutions prepared for biological tests showed color changing when kept for a few days on the laboratory bench, under room conditions, illuminated by common LED daylight tubes (4500–6000 k). This prompted us to investigate the possible photo-induced degradation of our compounds. FT-IR ATR experiments evidenced variations in the expected bands for functional of -amino-4H-pyran-3-carbonitriles stored under LED daylight. Following, HPLC–UV analysis showed reductions in the intensity of chromatographic peaks of 2-amino-4H-pyran-3-carbonitriles, and but not for solutions kept in the dark. A solution of (E)-2-amino-8-(4-nitrobenzylidene)-4-(4-nitrophenyl)-5,6,7,8-tetrahydro-4H-chromene-3-carbonitrile underwent 84.4% of conversion after 72 h of exposure to continuous LED daylight in a BOD chamber, and the reaction product was isolated in 36% yield and characterized as (E)-7-cyano-5-(4-nitrobenzylidene)-8-(4-nitrophenyl)bicyclo[4.2.0]oct-1(6)-ene-7-carboxamide (7*). Despite freshly prepared solutions of 2-amino-4H-pyran-3-carbonitriles produced antifungal activities, these solutions lost biological activity when left on the bench for a week. Besides, compound 7* formed from photo-induced degradation of 7 also showed no antifungal activity. With this, we hope to bring two contributions: (1) production of cyclobutenes through photochemical reactions of 2-amino-4H-pyran-3-carbonitriles can be carried out through exposure to simple white LED daylight; (2) biological applications of such 2-amino-4H-pyran-3-carbonitriles may be impaired by their poor photostability.

Hop - Humulus lupulus (Cannabaceae) - is an important and ancient, herbaceous, temperate, perennial crop. It is a vine which, although having other uses, is cultivated predominantly for the brewing industry (Laws 2013). Cultivation of hops in Brazil is relatively new and has increased in the last twenty years. There is only one published record of a fungal disease affecting hop in Brazil - powdery mildew (Fagherazzi et al 2021). In January 2021, leaf spots appeared on all eight hops plants ithe collection maintained in the Infectarium, a disease demonstration garden on the campus of the Universidade Federal de Viçosa (UFV), Viçosa, Minas Gerais, Brazil (https://www.infectario.ufv.br/). Symptoms were small, sub-circular to irregular spots, up to 5 mm, with a whitish to grayish center, surrounded by a dark brown necrotic margin, followed by a narrow yellowish outer margin. Older lesions became larger, grayish-brown, coalesced leading to extensive necrosis and stem dieback. A sample was collected, dried in a plant press, and deposited in the Herbarium of UFV (Acc. No VIC 47534). A dematiaceous fungus was found sporulating in the center of the lesions, when examined with a dissecting microscope. Fungal structures were scraped with a scalpel, mounted in lactoglycerol and observed with a light microscope (Olympus BX51). A pure culture was obtained after conidia were transferred onto PDA plates with a sterile fine-pointed needle. A representative isolate was deposited in the culture collection of the UFV (COAD 3368). The fungus had the following morphology: conidiophores cylindrical, geniculate, proliferating sympodially, 53 to 380 µm × 3 to 6.5 µm, 3 to 15-septate, smooth, with thickened and dark conidial scars, brown; conidia acicular to filiform, 47 to 210 µm × 2.5 to 5 µm, 3 to 17-septate, thin‑walled, smooth, with thickened and dark hila, hyaline. This combination is typical of Cercospora apii sensu lato, as described by Crous and Braun (2003). Genomic DNA was extracted from a 7-day-old culture of COAD 3368 and three loci were PCR amplified, namely: actin (ACT), with 512-F and 783-R primers; calmodulin (CAL), using the primers 228F and 2Rd; and histone H3 gene (HIS3), with the primers CYLH3F and CYLH3R. PCR products were sequenced by Macrogen (Seoul, South Korea) and the resulting sequences were deposited in GenBank (OM677624, OM677625 and OM677626, respectively). A multilocus Bayesian phylogenetic grouped COAD 3368 with Cercospora 'sp. Q' (Groenewald et al. 2013). This is a yet unresolved species complex within C. apii. Six 6‑month‑old healthy hop plants (cv. Cascade) were sprayed with a COAD 3368 conidial suspension (105 conidia/ mL) whereas another group of six plants was sprayed with sterile distilled water, serving as controls. Plants were placed in a dew chamber for 5 days and then transferred to a greenhouse bench, where they were observed daily. Thirty days after inoculation, symptoms similar to those observed in the field had developed on all inoculated plants, whereas control plants remained healthy. The fungus growing on inoculated hops produced typical Cercospora conidiophores and conidia. Upon reisolation, pure cultures with the same morphology of COAD 3368 were obtained. There are no previous records of Cercospora 'sp. Q' on hops worldwide. Fungi in Cercospora 'sp. Q' are known to have a broad host-range. A previous record of Cercospora 'sp. Q' leaf spots was published from its observation on Dioscorea cayennensis in the Infectarium (Torres et al. 2016). Damage to the hop plants was severe and it is possible that Cercospora leaf spot will become an emerging threat to commercial hop plantations in Brazil.

Ceratobasidium lantanae-camarae was a name proposed for a fungus associated with white thread blight disease of Lantana camara (common lantana): a Brazilian native plant listed amongst the world’s ten worst weeds. This fungus was found during surveys in Brazil to assess the potential of coevolved fungal pathogens as classical biocontrol agents in the Paleotropics and Australasia. Later, in a monograph on Rhizoctonia forming-fungi, C. lantanae-camarae was synonymized with C. cornigerum: a polyphagous species recorded worldwide, but never previously from Latin America. The lack of pure cultures of C. lantanae-camarae did not allow a verification of the true status of the white thread blight fungus on lantana. Recently, the lantana disease was observed in localities in the Brazilian states of Rio de Janeiro and Amazonas. Pure cultures were obtained, DNA was extracted and phylogenetic analyses of the ITS-5.8S rDNA region were performed. Results showed that C. lantanae-camarae and C. cornigerum are phylogenetically distinct and that their synonymization was a taxonomic error. It was also found that, although C. lantanae-camarae is phylogenetically close to C. papillatum, morphological differences between these two species are evident. Thus, the name C. lantanae-camarae is re-established herein: an epitype and a reference ex-epitype sequence are indicated, resolving this taxonomic issue. Additionally, Koch’s postulates were fulfilled for the first time. The significance of this taxonomic elucidation for weed biocontrol is discussed.

The synthesis and phytotoxic activity of a series of tyrosol 1,2,3-triazole derivatives are reported herein. Target compounds were synthesized through the copper(I)-catalyzed azide-alkyne cycloaddition reaction (CuAAC), known as click reaction, and these were tested for phytotoxic activity on leaves of wild poinsettia (

The initial objective of our work was to synthesize a series of 2-amino-4H-pyran-3-carbonitriles to be tested for their antifungal activities against economically relevant phytopathogenic fungi. Fourteen compounds were prepared in up to 94% yield and shown percentages of Botrytis cinerea inhibition above 70%. Despite the promising biological results, we observed that stock solutions prepared for biological tests showed color changing when kept for a few days on the laboratory bench, under room conditions, illuminated by common LED daylight tubes (4500-6000 k). This prompted us to investigate the possible photo-induced degradation of our compounds. FT-IR ATR experiments evidenced variations in the expected bands for functional of -amino-4H-pyran-3-carbonitriles stored under LED daylight. Following, HPLC-UV analysis showed reductions in the intensity of chromatographic peaks of 2-amino-4H-pyran-3-carbonitriles, and but not for solutions kept in the dark. A solution of (E)-2-amino-8-(4-nitrobenzylidene)-4-(4-nitrophenyl)-5,6,7,8-tetrahydro-4H-chromene-3-carbonitrile underwent 84.4% of conversion after 72 h of exposure to continuous LED daylight in a BOD chamber, and the reaction product was isolated in 36% yield and characterized as (E)-7-cyano-5-(4-nitrobenzylidene)-8-(4-nitrophenyl)bicyclo[4.2.0]oct-1(6)-ene-7-carboxamide (7*). Despite freshly prepared solutions of 2-amino-4H-pyran-3-carbonitriles produced antifungal activities, these solutions lost biological activity when left on the bench for a week. Besides, compound 7* formed from photo-induced degradation of 7 also showed no antifungal activity. With this, we hope to bring two contributions: (1) production of cyclobutenes through photochemical reactions of 2-amino-4H-pyran-3-carbonitriles can be carried out through exposure to simple white LED daylight; (2) biological applications of such 2-amino-4H-pyran-3-carbonitriles may be impaired by their poor photostability.

Neomarica is a genus of the Iridaceae with several ornamental species, including Neomarica caerulea (walking iris) and N. longifolia (yellow iris). Little is known about fungal diseases of members of the genus Neomarica. In June 2017, N. longifolia plants growing in a garden at Antonio Carlos were observed bearing leaf spots symptoms. A cercosporoid hyphomycete was associated with the necrotic tissues. It was conjectured that the fungus involved might be the same described causing leaf spots on N. caerulea in Brazil. Examination of the type of the species concerned (Cercospora neomaricae) revealed that this specimen was in very poor condition and inadequate for comparison. This prompted us to re-collect the fungus from the type locality for epitypification. Besides designating an epitype, a pure culture of C. neomaricae was obtained (ex-epitype culture) and a molecular study of this isolate together with the molecular and morphological analysis of the fungus on N. longifolia was performed. The fungus on N. longifolia was found to be morphologically and genetically clearly distinct from C. neomaricae. Analyses of the ITS, CAL and ACT regions indicated that the fungus on N. longifolia belongs to the Cercospora sp. H, which is an unresolved species complex, including several isolates obtained from various hosts.

Digitodesmium is a genus of saprobic fungi, generally associated with decaying wood in freshwater habitats or in the soil. As morphologic markers they produce cheiroid, euseptate conidia on sporodochia. During an exam of a necrotic robusta coffee stem sent from Nova Venécia, state of Espírito Santo, to the Plant Clinic at the Universidade Federal de Viçosa (Brazil), for disease diagnosis a fungus, recognized as having the typical features of Digitodesmium was observed. The fungus was isolated in pure culture and DNA was extracted. Sequences of the partial 18S ribosomal RNA gene, large subunit of the nrDNA, internal transcribed spacer and translation elongation factor 1-α were generated. The combination of results of the phylogenetic analysis with the exam of the morphology led to the conclusion that the fungus from coffee stem morphological data showed that this fungus represents a monophyletic distinct lineage within Digitodesmium and an undescribed species for the genus. The concatenate tree also revealed that Digitodesmium is divided in two distinct clades. The novel species can be differentiated morphologically from other species of Digitodesmium by the size of the conidia, the number of arms and the presence of appendages. The new species Digitodesmium polybrachiatum is hence proposed herein. A comparative table of conidial morphology for the species in the genus is also included.

Commelina benghalensis (tropical spiderwort - TS) is an invasive herbaceous plant, native to South and Southeast Asia and one of the worst agricultural weeds in the tropics. Its management is notoriously difficult because of its ability to regenerate from small fragments and its tolerance to glyphosate applications. There are no published records of biocontrol attempts against TS involving either microbial or arthropod natural enemies. Prior to investigating classical biocontrol agents, surveys have been conducted in Brazil and, more recently, concentrated in Vicosa (state of Minas Gerais) to determine whether fungal pathogens of TS are already present. Five different fungal pathogens were collected. These fungi were identified as causing the following diseases: Athelia rolfsii – crown rot, Cercospora cf. sigesbeckiae – leaf spots, Corynespora cassiicola – leaf spots, Neopyricularia obtusa sp. nov. – leaf spots and Rhizoctonia solani – blight. One of the fungi found on TS represents a new taxon, and the others represent either a new host association, a new geographic record or both, except for Corynespora cassiicola, which has already been recorded as able to attack TS (ex-tomato isolates, under controlled conditions) in Brazil. The mycobiota identified in Brazil is limited and lacks many of the TS-specific fungal pathogens recorded in Africa and Asia, namely: Kordyana celebensis, Kordyana indica, Phakopsora tecta, Puccinia commelinae, Uredo ochracea, Bauerago combensis and Bauerago commelinae. It is conjectured here, that such exotic fungi, may offer a valuable resource for management of one of the worst agricultural weeds in Brazil and in the tropical world, and require investigation as biological control agents for introduction in Brazil.

Gray mould of Neomarica longifolia (yellow iris) is reported here for the first time in Brazil and worldwide. The identity of the fungus was investigated and both morphology and molecular information demonstrated it to belong to Botrytis cinerea. Koch’s postulates were performed demonstrating that B. cinerea was the etiological agent of the disease.

Lonicera japonica (Japanese honeysuckle), a plant of Asian origin introduced as an ornamental into many countries, has become an invasive weed in some exotic situations, such as in southern Brazil. Classical biological control (CBC) with natural enemies collected in the centre of origin is considered to be the best alternative for sustainable management of L. japonica. In the context of this strategy, previous knowledge of the natural enemies already present in the target area is of great importance in order to avoid un-necessary introductions of CBC agents from the weed’s native range. Recently, examination of populations of L. japonica in localities in the Brazilian states of Rio de Janeiro and Paraná revealed the presence of leaf spots consistently associated with a cercosporoid hyphomycete. A molecular and morphological study of this fungus led to its recognition as Pseudocercospora lonicerigena. There were few differences when the Brazilian isolate was compared with a strain found in North America. This is the first report of this fungus in Brazil. The fungus was isolated in pure culture and inoculation of healthy leaves of L. japonica eventually led to leaf yellowing and necrosis, indicating that P. lonicerigena is not highly pathogenic, as evidenced by the continuing advance of this weed in southern Brazil. Therefore, the introduction of additional co-evolved natural enemies collected in Asia, perhaps piggy-backing on an ongoing project already underway in New Zealand, will be necessary to control this invasive alien weed in Brazil.