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Global warming is affecting plant phenology, with potential consequences on the dynamics of growth reactivation of sugar maple and the timings of maple syrup production. In this study, we assess the temperatures inducing the daily reactivation or cessation of sap production. We selected 19 sugarbushes across Quebec, Canada, using a tapping method associated with the tubing system, we recorded the daily timings of onset and ending of sap production during winter and spring 2018, and we associated the hourly temperatures at each site. Sap production occurred from mid-February to the end of April, starting on average between 10 and 11 AM, and ending from 6 to 8 PM. We observed a seasonal pattern in the onset and ending of sap production during spring, with the onset showing a greater change than the ending. Onset and ending of sap production occurred mostly under temperatures ranging between -2 and 2 °C. The production of sap in maple is closely related to circadian freeze-thaw cycles and occurs under nighttime and daytime temperatures fluctuating below and above 0 °C. The daily lengthening of the duration of sap production mirrors the changes in the timings of freeze and thaw events and can be explained by the physical properties of the water and the physiological processes occurring during growth reactivation. The ongoing warming will result in earlier and warmer springs, which may anticipate the cycles of freeze and thaw and advance sap production in sugar maple.

Made available in DSpace on 2021-07-14T10:42:06Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-05-17. Added 1 bitstream(s) on 2021-07-14T11:36:16Z : No. of bitstreams: 1 S0100-54052021000100038.pdf: 3776165 bytes, checksum: 82fef0f03ba43118a6dd0407531cc1fd (MD5) O gênero Khaya engloba importantes espécies florestais produtoras de madeira, cujo lenho é utilizado principalmente na indústria moveleira e na construção civil. Dentre os membros desse gênero, Khaya senegalensis é uma das espécies mais cultivadas no Brasil. A murcha-de-ceratocystis está entre as principais doenças dessa cultura, se tornando limitante caso não manejada adequadamente. Até o momento não foram conduzidos estudos epidemiológicos envolvendo essa patologia em K. senegalensis. O objetivo deste trabalho foi caracterizar a disseminação da murcha-de-ceratocystis em K. senegalensis, por meio da técnica de Análise da Dinâmica e Estrutura de Focos (ADEF) e do Índice de Dispersão (ID). Instalou-se três parcelas com 540 indivíduos cada no interior de um talhão puro dessa espécie florestal. A quantificação da doença foi realizada anualmente de 2016 a 2018, sendo elaborados mapas de dispersão das plantas doentes, os quais serviram de base para as análises. Pela ADEF, observou-se o padrão agregado em todas as parcelas e anos avaliados, com focos apresentando crescimento isodiamétrico. No entanto, pela técnica do ID, o padrão variou entre ao acaso e agregado, em função do tamanho do quadrat utilizado na análise. Pelo tamanho dos focos observados na área experimental, recomendou-se o uso de quadrats maiores no ID, que indicaram um padrão agregado na maior parte das parcelas. Pôde-se concluir que no patossistema estudado houve tendência a agregação das plantas doentes, com uma provável participação da ferramenta de poda no processo de disseminação e/ou infecção pelo agente causal. The genus Khaya includes important forest species, whose wood is used mainly in the furniture industry and civil construction. Khaya senegalensis is one of the most cultivated species in Brazil. Ceratocystis wilt is one of the main diseases of this culture, offering a serious risk if not properly managed. However, no epidemiological studies have been conducted involving this pathology in K. senegalensis. The objective of this work was to characterize the spread of Ceratocystis wilt in K. senegalensis, using the Dynamics and Foci Structure Analysis technique (DFSA) and the Dispersion Index (DI). Three plots with 540 individuals each were installed inside a plantation of this species. The quantification of the disease was done annually from 2016 to 2018, with the elaboration of dispersion maps of diseased plants, which served as the basis for all the analyzes performed. According to DFSA, the aggregate pattern was observed in all plots and years evaluated, with disease foci showing isodiametric growth. However, using the ID technique, the pattern varied between random and aggregate, depending on the size of the quadrat used. Due to the size of the foci observed in the experimental area, the use of larger quadrats in the ID was recommended, which indicated an aggregate pattern in most plots. Thus, it was possible to conclude here was a tendency for the aggregation of diseased plants, with a probable participation of the pruning tool in the process of spreading and/or infection by the causal agent. Universidade Estadual Paulista “Júlio de Mesquita Filho”, Faculdade de Ciências Agronômicas Futuro Florestal Universidade Estadual Paulista “Júlio de Mesquita Filho”, Faculdade de Engenharia Universidade Federal de São Carlos, Campus de Lagoa do Sino. Rodovia Lauri Simões de Barros Universidade Estadual Paulista “Júlio de Mesquita Filho”, Faculdade de Ciências Agronômicas Universidade Estadual Paulista “Júlio de Mesquita Filho”, Faculdade de Engenharia

Made available in DSpace on 2021-07-14T10:42:05Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-09-21. Added 1 bitstream(s) on 2021-07-14T11:36:15Z : No. of bitstreams: 1 S0100-54052020000300273.pdf: 1477889 bytes, checksum: f73ff883db74d4b0d6ab1bdaa223e5a5 (MD5) Universidade Estadual Paulista “Júlio de Mesquita Filho”, Faculdade de Ciências Agronômicas Universidade Estadual Paulista “Júlio de Mesquita Filho”, Faculdade de Ciências Agronômicas

Valeriana officinalis L. (valerian, garden valerian) is a perennial herbaceous plant in the Valerianaceae family, commonly used as a medicinal herb in the treatment of insomnia and nervousness. In May 2019, at Botucatu city in Sao Paulo state (22°53′25″S, 48°27′19″W), 80% of production of valerian plants from a grower were observed to show symptoms typical of southern blight that included leaf wilt and the presence of sclerotia in rotted tissue. Symptoms on infected plants began with yellowing of older leaves from the base to the apex that was accompanied by a brown rot in which sclerotia were formed. The suspect fungal pathogen was tentatively identified as Sclerotium rolfsii (teleomorph Athelia rolfsii) based on its morphological characters and the signs and symptoms of the fungus. Efforts to isolate the fungus for use in pathogenicity tests were made by surface disinfecting infected tissue for 1 min in 70% alcohol and then 2 min in 2% NaOCl, followed by immersion in sterile distilled water. Tissue pieces were then placed in plates containing potato dextrose agar and maintained at 25°C. White mycelia and sclerotia formed in these plates after 7 to 14 days. Sclerotia were brown, ellipsoid in shape, and ranged from 0.82 to 1.8 cm in diameter (average 1.42 cm, n = 100). These dimensions were similar to those obtained by Erper et al. (2019) from S. rolfsii that infected candyleaf in Turkey. A culture of our valerian isolate was deposited in the collection of the Biological Institute of Sao Paulo under accession number MMBF 04/20. Pathogenicity tests were conducted on healthy 2-month-old valerian plants in a greenhouse maintained at 25°C and 95% relative humidity (RH) for 3 days and at 25°C and 70% RH the following 8 days. Sclerotia were incorporated into the soil near four plant stem repetitions as the method of inoculation, and four noninoculated valerian plants were the control. Disease symptoms began to appear 3 days postinoculation, sclerotia formed after 9 days, and plant death occurred within 11 days. Symptoms on inoculated plants were the same as those observed on the original diseased specimens, and control plants remained healthy. S. rolfsii was reisolated from sclerotia produced on inoculated plants, thus confirming Koch’s postulates. DNA for molecular identification was extracted from our isolate of S. rolfsii using the cetyltrimethylammonium bromide method according to Doyle and Doyle (1987). This was followed by a polymerase chain reaction using primers ITS1/ITS4, which amplify part of the internal transcribed spacer region (White et al. 1990). The amplicon obtained (GenBank accession no. MT023434) was bidirectionally sequenced and shared 97.05% sequence identity with A. rolfsii (593/611 nucleotide identity, MH854711). S. rolfsii is known to infect many economically important plants (Tu and Kimbrough 1978). It has been reported from Japan on Valeriana radix (Morita et al. 2015), in India on V. jatamansi (syn. V. wallichii) (Khosla 2014), and in Korea on V. fauriei (Kwon et al. 2010). In Brazil, other medicinal plants such as Taraxacum officinale (dente de leao) (Severino et al. 2014) and Plantago major (tanchagem) (Dias-Arieira et al. 2014) have been reported to be susceptible to infection by S. rolfsii. To our knowledge, this is the first report of the occurrence of S. rolfsii on valerian in Brazil.