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Submitted by Maria Cândida de Godoy Gasparoto (maria.candida@unesp.br) on 2021-08-20T13:44:00Z No. of bitstreams: 1 Gasparoto et al 2021 First Look - Repositório.pdf: 2550316 bytes, checksum: 24271d4e581fde04f2da07713c13d3e7 (MD5) Approved for entry into archive by Luana Priscila Costa (luana@reitoria.unesp.br) on 2021-09-15T19:12:52Z (GMT) No. of bitstreams: 1 gasparoto_mc_preprint_regi_prevalent.pdf: 2550316 bytes, checksum: 24271d4e581fde04f2da07713c13d3e7 (MD5) Made available in DSpace on 2021-09-15T19:12:52Z (GMT). No. of bitstreams: 1 gasparoto_mc_preprint_regi_prevalent.pdf: 2550316 bytes, checksum: 24271d4e581fde04f2da07713c13d3e7 (MD5) Previous issue date: 2021-08-19 Outra Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) In Brazil, citrus huanglongbing (HLB) is associated with ‘Candidatus Liberibacter americanus’ (CLam) and ‘Ca. Liberibacter asiaticus’ (CLas). However, there are few studies about HLB epidemiology when both Liberibacter spp. and its insect vector, the Asian citrus psyllid (ACP, Diaphorina citri), are present. The objective of this work was to compare the transmission of HLB by ACP when both CLam and CLas are present as primary inoculum. Two experiments were performed under screenhouse conditions from April 2008 to January 2012 (experiment 1) and from February 2011 to December 2015 (experiment 2). The experiments were carried out with sweet orange plants infected with CLam or CLas as inoculum source surrounded by sweet orange healthy plants. One hundred Liberibacter-free adult psyllids were monthly confined to the source of inoculum plants for 7 days with subsequent free movement inside the screenhouse. Fortnightly, nymphs and adults of psyllids were monitored. Psyllid and leaf samples were collected periodically for Liberibacter detection by PCR or qPCR. CLas was detected more frequently than CLam in both psyllid and leaf samples. No mixed infections were detected in the psyllids. A clear prevalence of CLas over CLam was observed in both experiments. The final HLB incidences were 16.7 and 14.5% of Liberibacter-positive test plants, and CLas was detected in 92.3 and 93.1% of these infected plants. Mixed infection was observed only in 3.8% of infected test plants in experiment 1. These results endorse the shift in the prevalence of CLam to CLas observed in citrus orchards of São Paulo, Brazil. Postprint Universidade Estadual Paulista "Júlio de Mesquita Filho" (Unesp) Fundo de Defesa da Citricultura (Fundecitrus) Universidade de São Paulo (Usp) FAPESP: 2007/55013-9 FAPESP: 2007/52040-5 FUNDECITRUS: 043012 Citrus Research Development Foundation: NAS7

Made available in DSpace on 2020-12-10T20:00:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-06-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Postbloom fruit drop (PFD) of citrus is caused by the Colletotrichum acutatum and C. gloeosporioides species complexes. The disease is important when frequent rainfall occurs during the flowering period of citrus trees. In Brazil, until 2012, PFD was mainly controlled by preventive applications of the methyl-benzimidazole carbamate (MBC) carbendazim and demethylation-inhibitor (DMI) fungicides such as difenoconazole. Since then, mixtures containing the DMI tebuconazole and the quinone-outside inhibitor (QoI) trifloxystrobin have been commonly used. Fungicides are often applied preventively, sometimes even when conditions are not conducive for PFD development. Excessive fungicide applications may favor the selection of resistant populations of Colletotrichum spp. In this study, we assessed the fungicide sensitivity of C. acutatum isolates collected during the two distinct periods of PFD management in Brazil: before and after the trifloxystrobin and tebuconazole mixture became widely employed. The sensitivity of 254 C. acutatum isolates to carbendazim and difenoconazole and of 164 isolates to tebuconazole and trifloxystrobin was assessed. Mycelial growth inhibition of these isolates was evaluated for all the fungicides using either serial dilution of fungicide rates or the spiral gradient dilution method. In addition, inhibition of conidial germination was also assessed for trifloxystrobin. Analysis of partial beta-tub, cytb, and cyp51b gene sequences did not reveal any mutations related to resistance to MBCs, QoIs, and DMIs, respectively. In mycelia] growth assays, mean EC50 values were 0.14, 0.11, and 0.21 mu g/ml for difenoconazole, tebuconazole, and trifloxystrobin, respectively. The conidial germination inhibition by trifloxystrobin was similar among the tested isolates, and the mean EC50 value was 0.002 mu g/ml. All isolates had similar mean mycelial growth inhibition for carbendazim, regardless of the fungicide concentrations. Therefore, based on similar EC50 values and molecular analyses, no shift in the sensitivity of isolates has been observed to the fungicides commonly used in different citrus-producing areas in Brazil. Univ Sao Paulo, Escola Super Agr Luiz Queiroz, BR-13418900 Piracicaba, SP, Brazil Univ Florida, Gulf Coast Res & Educ Ctr, Wimauma, FL 33598 USA Sao Paulo State Univ, Campus Expt Registro, Registro, SP, Brazil Fundo Defesa Citricultura Res & Dev, BR-14807040 Araraquara, SP, Brazil Sao Paulo State Univ, Campus Expt Registro, Registro, SP, Brazil CNPq: 2015/06007-2

Made available in DSpace on 2020-12-12T02:40:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-05-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Some benefits of silicon (Si) fertilization have been reported in sugarcane plants, but information about the effects of Si on brown rust (Puccinia melanocephala) remain scarce, even though this plant disease is widespread in several areas around the world. The objective of this study was to evaluate whether Si potentiates the production of antimicrobial metabolites in sugarcane plants in response to infection by P. melanocephala. Experiments with a sugarcane cultivar (SP70–1143) susceptible to brown rust were conducted in pots (3 L) under greenhouse conditions using a randomized complete block design with four treatments: with and without Si (equivalent to 0 and 800 kg ha−1 of Si, denominated -Si and + Si, respectively), sprayed with water or inoculated with a suspension of P. melanocephala urediniospores. Liquid potassium silicate was applied in soil as a source of Si. Si fertilization increased soil Si and Si concentration in plants, which correspondingly decreased brown rust severity and sporulation of P. melanocephala in leaves. Silicon fertilization increased the concentration of sucrose and cis-aconitic acid and reduced the concentration of chlorogenic acid (trans-3-caffeoylquinic acid) in sugarcane leaves inoculated with the pathogen. In vitro germination of P. melanocephala was reduced in contact with all metabolites isolated by UHPLC-DAD (chlorogenic acid and C-glycosylated flavones) from the sugarcane leaves. This work helps to elucidate the potential prophylactic role of Si in the interaction between P. melanocephala and sugarcane. Agência Paulista de Tecnologia dos Agronegócios (APTA), P.O. Box 28 Instituto de Química Universidade Estadual Paulista “Júlio de Mesquita Filho” (UNESP), Rua Prof. Francisco Degni, 55 Departamento de Fitopatologia e Nematologia ESALQ/Universidade de São Paulo (USP), P.O. Box 9 Departamento de Ciências Biológicas ESALQ/Universidade de São Paulo (USP), P.O. Box 9 Embrapa Instrumentação, Rua XV de Novembro, 1452 Instituto de Química Universidade Estadual Paulista “Júlio de Mesquita Filho” (UNESP), Rua Prof. Francisco Degni, 55 FAPESP: 2008/10795-2 FAPESP: 2018/05843-0

Postbloom fruit drop (PDF) is an important citrus disease that causes up to 100% yield losses during years in which conditions are favourable for the occurrence of epidemics. The conidia of Colletotrichum acutatum and C. gloeosporioides, causal agents of PFD, are predominantly dispersed by rain splash. At the beginning of epidemics, the distribution of diseased plants is random and the disease progress rate is very high, which is unusual for pathogens spread by rain splash. As the pathogen produces abundant conidia on diseased petals, pollinating insects may contribute to disease dispersal. This study investigated honeybees (Apis mellifera) as dispersal agents of C. acutatum and C. gloeosporioides among citrus plants. Two experiments were carried out in a screenhouse in which citrus plants were protected (or not) in insect-proof cages. The source of inoculum was placed on one side of the screenhouse, and a honeybee hive was placed on the opposite side. All uncaged plants showed symptoms of the disease, and none of the caged plants exhibited PFD symptoms. The monomolecular model showed a good fit to disease progress in both experiments. Conidium-like structures of Colletotrichum spp. were identified attached to the bodies of the honeybees by scanning electron microscopy. These results have revealed that honeybees disperse Colletotrichum among citrus plants. This article is protected by copyright. All rights reserved.

Rhizopus rot, caused by Rhizopus stolonifer, is a major postharvest disease of stone fruits. The disease is related to the occurrence of mechanical and physical damage; however, observations at a Brazilian wholesale market suggest that direct penetration can occur. Therefore, the penetration mechanisms of R. stolonifer in stone fruits were evaluated. To identify the production of enzymes that help with direct penetration by the pathogen, esterase activity, both in mycelial discs and in spore suspensions of the fungus in water and in modified Van Etten nutrient solution, was measured. Assays were also conducted to evaluate the growth of R. stolonifer on glucose or cutin as a sole carbon source. The pathogen grew on both media, and higher esterase activity was observed in the cutin medium. Wounded and unwounded peaches and nectarines were inoculated with R. stolonifer spore suspensions in water or in modified Van Etten nutrient solution. Wounded fruit inoculated with either of the R. stolonifer spore suspensions developed rhizopus rot, whereas unwounded fruit developed the rot only in the presence of spores in the modified Van Etten nutrient solution. Scanning electron and light microscopic examination showed the fungus can directly penetrate the nectarine cuticle. Diisopropyl fluorophosphate, a serine hydrolase inhibitor, prevented rot development in peaches. The results provide valuable evidence for the ability of R. stolonifer to directly penetrate unwounded stone fruits, probably due to the production of esterase enzymes.

The objectives of this work were (i) to determine the influence of temperature on infection of citrus by ‘Candidatus Liberibacter asiaticus’ and ‘Candidatus Liberibacter americanus’, the two bacterial species associated with citrus huanglongbing (HLB) in Brazil, and (ii) to determine the influence of temperature on citrus colonization by ‘Ca. L. asiaticus’, which has taken over from ‘Ca. L. americanus’ as the predominant species in Brazil since 2008. Two experiments were carried out with graft-inoculated Valencia oranges on Rangpur lime rootstocks. Immediately after inoculation the plants were maintained for 423 days in growth chambers under the following night ⁄day temperature conditions: 17 ⁄22, 22 ⁄27 or 27 ⁄32� C, with a dark ⁄light photoperiod of 8 ⁄16 h. Infection and colonization of plants were determined using quantitative PCR (qPCR). ‘Candidatus Liberibacter americanus’ did not infect the plants maintained at 27 ⁄32� C; however, infection by ‘Ca. L. asiaticus’ occurred at all studied temperatures. Two months after inoculation, ‘Ca. L. asiaticus’ was distributed throughout the inoculated plants, with mean Ct values in the range of 30‐31 for leaves and 25‐28 for roots. Over time, ‘Ca. L. asiaticus’ reached the highest titres in mature leaves (mean Ct value = 26AE7) of citrus plants maintained at 22 ⁄27� C. ‘Candidatus Liberibacter asiaticus’ colonization of citrus plants was negatively affected by the daily temperature regime of 27 ⁄32� C( meanCt value in mature leaves = 33AE6).

Citrus Variegated Chlorosis (CVC) caused by Xylella fastidiosa is one of the most important diseases for Brazilian citriculture. The CVC is a vascular disease with a long incubation period and symptoms similar to other disorders, and this factors difficult the CVC quantification in the field. Two methods of CVC assessment were compared in this study. The first method was based on a descriptive rating scale with four ratings, commonly used for the disease quantification. The second one was based on the incidence of symptomatic branches. The quantification of CVC through these two methods was carried out in a 10-year-old 'Natal' sweet orange orchard. The descriptive scale considered the symptoms of the entire plant. The disease incidence was evaluated in 36 branches in each plant. The assessments were conducted by three raters in 144 plants in July 2006 and July 2007 as well as in March and November 2008. The descriptive scale did not allow an accurate assessment and resulted in a moderate strength of agreement among the raters. On the other hand, the incidence quantification of CVC through the symptomatic branches showed high repeatability among the raters. We suggest the use of incidence of symptomatic branches as variable for CVC quantification. National Council for Scientific and Technological Development (CNPq)

The aim of this work was the characterisation of the environmental and superficial mycoflora of equipment and facilities of two citrus packing houses in Sao Paulo State, Brazil, in 2004 and 2005. One of the packing houses packed fruit for the export market (municipality of Matao), the other for the domestic market (municipality of Engenheiro Coelho). The study also identified the presence of isolates of Penicillium spp. resistant to thiabendazole and imazalil fungicides in packing houses. The environmental mycoflora was sampled according to the gravimetric method, using Petri dishes containing potato dextrose agar medium opened for 2 min. The superficial mycoflora on equipment and facilities was sampled with Rodac plates. The mycoflora in the environment and on surfaces of the packing houses in Matao were 12.3 and 52.3 cfu/plate, respectively, while these populations for the Engenheiro Coelho packing house were 46.3 and 68.2 cfu/plate, respectively. Cladosporium and Penicillium were the most prevalent genera of fungi. The contamination levels of clean zones in the packing houses (washing of fruits, packing table, boxes and containers) was not substantially lower than the contamination in dirty zones (reception of fruits and first selection). The percentage of P. digitatum isolates in Matao that was resistant to thiabendazole and imazalil was 25.9 and 1.5 in the environment and 30.1 and 16.0 on packing house surfaces, respectively. In Engenheiro Coelho, percentage of resistance to these fungicides was 51.9 and 0.1 in the environment and 39.2 and 0.9 on packing house surfaces, respectively.

O mofo-branco, causado por Sclerotinia sclerotiorum, e uma doenca importante na cultura do tomateiro. O objetivo do trabalho foi avaliar o efeito de extratos de plantas, residuos animais e subprodutos industriais no desenvolvimento micelial e na producao de esclerodios do fungo "in vitro". Os tratamentos testados foram diferentes concentracoes de licor pirolenhoso, oleo de nim, glutamato monossodico, biossolido e composto orgânico [(borra de cafe (50%) cinza de carvao (10%), residuo de milho (25%), esterco de aves (12,5%) e farinha de aves (2,5%)], alem de duas testemunhas, sem adicao de produtos ao meio e com adicao do fungicida procimidone. O fungo submetido aos diferentes tratamentos foi incubado a temperatura de 22oC e luminosidade constante de 260 lux. Foram avaliadas o crescimento micelial, a producao de esclerodios e a viabilidade dos mesmos aos 7 e 17 dias apos a repicagem do fungo para meio de neon. O composto orgânico a 30 % mostrou-se eficiente na inibicao do crescimento micelial e na producao de esclerodios. Este tratamento, assim como o oleo de nim a 0,5%, foi analisado com relacao a sua influencia na microbiota no solo por meio de uma analise de respirometria, que indicou que ambos os tratamentos foram degradados rapidamente, nao causando assim maleficios a mesma.

Brown rot, caused by Monilinia spp. , is one of the most important peach (Prunuspersica (L.) Batsch) diseases and the main cause of postharvest losses. Currently, alternative methods for postharvest disease control, such as the use of volatiles, are under investigation. The objective of this study was to determine the effects of hexanal on the in vitro development of Monilinia fructicola and M. laxa and on monocyclic components of brown rot on peaches. To evaluate the effect on pathogen development in vitro, a single dose of 215 µL of liquid hexanal was placed on glass jars in closed plastic containers (4.3 L) at the moment of fungi transfer, 24 or 48 h after transferring to Petri dishes. After hexanal application, the Petri dishes were kept inside the containers that were closed for 24 h at 20 ºC. Mycelial growth was measured seven days after hexanal removal. For in vivo assays, inoculated fruits were kept in closed plastic containers, and hexanal was applied at the moment of fruit inoculation or 24 hours thereafter. The monocyclic components infection frequency, expressed as brown rot incidence, lesion diameter and lesion sporulation, were assessed daily for seven days. Overall, hexanal was more effective in inhibiting mycelial growth when applied at the moment of pathogen transfer. Hexanal did not prevent pathogen infection, but reduced lesion diameter and completely inhibited spore production on the fruit for both treatments. Hexanal provides a promising alternative for chemical control and can be used in postharvest handling systems.

Este trabalho objetivou caracterizar os danos pós-colheita e as características físico-químicas de frutos de laranjas ‘Pêra’ e ‘Lima’ e de tangor ‘Murcott’ comercializados na Ceagesp SP, bem como caracterizar a micoflora ambiental nos pontos de revenda de citros da Ceagesp, em 2006. Frutos cítricos foram coletados de atacadistas e armazenados durante 14 dias a 25ºC e 85-90% de UR. A incidência de injúrias foi avaliada visualmente a cada três dias. As variáveis físico-químicas analisadas foram acidez titulável e teor de sólidos solúveis. A micoflora ambiental foi amostrada mediante o método gravimétrico, com placas de Petri, contendo meio batata-dextrose-ágar+pentabiótico, abertas por dois minutos. A incidência de podridões em laranjas ‘Pêra’ e ‘Lima’ e tangor ‘Murcott’ atingiu valores médios de 12,8; 14,9 e 25,8%, respectivamente, ao final do armazenamento, sendo o bolor verde a principal doença pós-colheita. Associações entre os parâmetros físico-químicos de maturação e a incidência de podridões foram, em geral, não significativas. A população fúngica ambiental variou significativamente entre os meses amostrados, com média de 25,3 ufc/placa e os gêneros Penicillium e Cladosporium foram os mais abundantes. Observou-se correlação positiva (r=0,96) entre a freqüência de P. digitatum encontrada no ambiente dos atacadistas e o bolor verde em laranja ‘Pêra’ comercializada. Entretanto, para laranja ‘Lima’ e tangor ‘Murcott’ tal correlação não foi verificada. The purposes of this work were to characterize postharvest injuries and to evaluate the physicochemical characteristics of ‘Pêra’ and ‘Lima’ oranges and ‘Murcott’ tangor at Ceagesp market, as well as to characterize the environmental mycoflora in retail points at Ceagesp in 2006. Fruits collected at retail points were stored for 14 days at 25ºC and 85-90% RH. The incidence of injuries was visually evaluated every three days. The physicochemical characteristics analyzed were titratable acidity and soluble solids amount. The environmental mycoflora was sampled according to the gravimetric method, using Petri dishes containing potato-dextrose-agar medium+pentabiotic opened for two minutes. The average rot incidences in ‘Pêra’ and ‘Lima’ oranges and ‘Murcott’ tangor were 12.8, 14.9 and 25.8%, respectively, at the end of the storage period, and green mold was the main postharvest disease. Associations between physicochemical parameters and rot incidence was, in general, not significant. The environmental fungal population varied significantly between the sampling months in retail points with an average of 25.3 cfu/plate. Penicillium and Cladosporium were the most recorded genera of fungi. Positive correlation (r=0.96) was observed between frequency of P. digitatum found in the environment of retail points and the green mold in on-sale fruits of ‘Pêra’ orange. However, for ‘Lima’ orange and ‘Murcott’ tangor such a correlation was not verified.