Edson Luiz Furtado

The genus Sirex (Hymenoptera: Siricidae) consists of 29 species including the Sirex Woodwasp, Sirex noctilio, which is the main insect pest of pine plantations in the Southern Hemisphere including Brazil. In 2023, a species of Sirex similar to S. noctilio was discovered in Southeastern Brazil infesting pine plantations and causing tree mortality of up to 40%. We definitively identified this species as Sirex obesus based on both morphological characters and DNA barcodes. It is a species indigenous to the Southwestern United States and Northern and Central Mexico with little information available regarding its biology and control. This is the first record of S. obesus in Brazil and the first record of the species outside of North America. We document details about S. obesus occurrence in Brazil, describe preliminary damage caused in pine plantations and provide a partial list of natural enemies.

O presente trabalho teve o objetivo de identificar espécies de Botryosphaeriaceae associadas à podridão pós-colheita em abacates ‘Hass’ provenientes dos Estados de São Paulo e Minas Gerais. Quarenta isolados foram submetidos à caracterizações: cultural, morfológica, patogênica e filogenética. A caracterização cultural e morfológica foi avaliada em meio de cultura, sob temperatura de 25ºC; a patogenicidade foi avaliada através do diâmetro de lesões em abacates inoculados com discos de micélio; e a caracterização filogenética se deu a partir das regiões ITS e Alfa elongase. Todos os isolados apresentaram colônias com micélio aéreo, cotonoso e de coloração preta a partir do nono dia de crescimento. Os conídios apresentaram formato fusiforme, colocação hialina, parede fina, geralmente asseptados ou pendendo a apresentar septos quando maduros. Diferenças entre os isolados foram observadas para os parâmetros crescimento micelial, tamanho dos conídios e diâmetro de lesões em frutos inoculados. Na caracterização filogenética foram identificadas três espécies pertencentes ao gênero Neofusicoccum: trinta e oito isolados pertencentes a espécie N. parvum, um de N. ribis e um de N. umdonicola, sendo este último a primeira vez sendo relatado em abacate no Brasil. Estas informações podem colaborar no processo de quarentena e nas estratégias de manejo destes patógenos.

The objective of this work was to evaluate the development of Davidiella sp. and its asexual form, Cladosporium sp., under different environmental conditions in the rubber tree (Hevea brasiliensis). Rubber tree leaves were inoculated with a spore suspension and kept in a humid chamber under different temperatures and wetness periods. The behavior of the fungi was evaluated using a scanning electron microscope (SEM) and an ultraviolet light microscope (UV). In the images obtained in SEM, four hours after inoculation of the fungus, it was possible to verify the germination and penetration of conidia at temperatures of 10 to 20 °C. The formation of conidiophores was verified from six hours after inoculation, indicating that it is in the reproductive period. In the sexual phase, in SEM, from four hours after inoculation, it was possible to verify the formation of small protuberances at temperatures between 10 and 20 °C. These black dots evolve into circular, protruding black spots, like the symptoms of black crust, with apparent spore formation on them. The data obtained from the UV analyses corroborate those from SEM, showing that the fungus has good development in its two phases between temperatures of 20 and 25 °C and that the period of wetness on the leaf can contribute to the initial development of the pathogen.

The plantation and natural forests of South America have been highly impacted by native and exotic pests in recent decades. The interaction of emerging invasive pests, climate change, and timber markets will define the region’s forests, with significant but uncertain ecological changes and economic losses expected. The Southern Cone Forest Health Group (SCFHG), a joint ad hoc initiative run by forest health professionals from Argentina, Brazil, Chile, and Uruguay, aims to strengthen relationships between the forestry industry, stakeholders, academia, and government agencies across the region. Here, we highlight regional strengths, weaknesses, threats, and opportunities to address forest health issues in the region. A regional approach with a strong communication network is relevant for future actions. In the current global scenario of invasive species and climate change, the implementation of practices that incorporate the resilience of forest ecosystems and sustainable management needs to be prioritized in forest policy across the region. Understanding that pests and pathogens do not recognize borders, we call on governments and organizations to support joint actions with agreements and adequate resources to enhance our regional capabilities.

Este trabalho teve como objetivo avaliar a degradação biológica e a durabilidade natural de espécies florestais da Amazônia em campo de apodrecimento em Rio Branco no Estado do Acre. O trabalho foi desenvolvido no campo experimental da Embrapa Acre entre 2015 e 2022. As estacas medindo 0,05 x 0,05 x0,50 metros, foram distribuídas e enterradas aleatoriamente no campo de apodrecimento a 0,25 m de profundidade. As avaliações de campo foram realizadas trimestralmente registrando-se a incidência de fungos xilófagos e cupins e os danos provocados em estacas de 36 espécies florestais. As espécies de fungos e cupins foram coletados e mantidos nos Laboratórios de Fitopatologia e Entomologia da Embrapa Acre e identificados em diversos laboratórios especializados no Brasil. A degradação das estacas foi realizada com a metodologia proposta por Lepage (1970), atribuindo notas de zero a quatro conforme a percentagem de degradação variando. Os fungos manchadores de madeiras identificados nesta pesquisa foram: Aspergillus, Fusarium, Penicillium, Trichoderma, Nigospora, Lasodiploidia, Cladosporium e Curvullaria. Os fungos apodrecedores de madeiras que ocorreram nas estacas foram: Gloeophyllum striatum, Hexagonia hidinoide, Datronia scutellata, Tramets e Picnoporus. Foram identificadas 11 espécies de termitas; A principal espécie de cupim T. teneus foi responsável por 91,6% das ocorrências. A espécie mais atacada H. tenuis foi o cedro rosa e aquela menos atacada foi o angelim-da-mata. As espécies canelão, freijó e a imbiridiba-amarela não foram infestadas por cupins. As espécies madeireiras que obtiveram o maior índice de degradação foram o mulungu duro, louro Itaúba, mulateiro, marupá preto.

The fungus Austropuccinia psidii infects young tissues of Eucalyptus plants until they are two years old in the nursery and field, causing Myrtaceae rust. The characteristics making older eucalypt leaves resistant to A. psidii and the reason for the low levels of this pathogen in older plants need evaluations. The aim of this study was to evaluate the morphological differences between Eucalyptus grandis leaves of different growth stages and two plant ages to propose a visual phenological scale to classify E. grandis leaves according to their maturation stages and to evaluate the time of leaf maturation for young and adult plants. A scale, based on a morphological differentiation for E. grandis leaves, was made. The color, shape and size distinguished the leaves of the first five leaf pairs. Anatomical analysis showed a higher percentage of reinforced tissue, such as sclerenchyma-like tissue and collenchyma, greater leaf blade thickness, absence of lower palisade parenchyma in the mature leaves and a higher number of cavities with essential oils than in younger ones. Changes in anatomical characteristics that could reduce the susceptibility of older E. grandis leaves to A. psidii coincide with the time of developing leaf resistance. Reduced infection of this pathogen in older plants appears to be associated with a more rapid maturation of their leaf tissues.

In recent years, a disease called black crust has caused damage to rubber trees in Brazil, since it leads to rapid leaf fall and consequently low latex production. Until the 1990s, black crust was associated with the fungi Phyllachora huberi and Rosenscheldiella heveae, but in 2022, after analysis of samples collected in the states of Minas Gerais and São Paulo, different species of the fungus Cladosporium ssp. were isolated from rubber tree leaves showing black crust in their leaflets. After morphological and phylogenetic analysis, using partial sequences of ITS-5.8S rDNA, α-elongase and actin regions, the isolates were identified as Cladosporium pseudocladosporioides, C. tenuissimum, C. cladosporioides, C. perangustum and C. xanthochromaticum. Pathogenicity tests with these isolates, in a greenhouse, demonstrated rapid appearance of symptoms such as apical death, damage to stems, intense defoliation and presence of black crust on stems and leaves. All isolates were pathogenic but had variable aggressiveness. This is the first report of Cladosporium causing black crust on rubber trees in Brazil.

Anthracnose, caused by fungi of the genus Colletotrichum, is present in the main areas where rubber trees (Hevea brasiliensis) are planted. Thus, considering that biological agents can be an alternative for disease control, the present study aimed to carry out initial studies to investigate the response of rubber tree seedlings inoculated with Colletotrichum and treated with saprobes fungi from the semiarid region of Northeast Brazil (Curvularia eragrostidis, Memnoniella levispora, Myrothecium roridum and Phialomyces macrosporus). Seedlings of the rubber tree clone RRIM600 were sprayed with biocontrol agents as preventive and curative treatments seven days before and after C. tamarilloi inoculation, respectively. Assessments included plant response to disease expression based on the percentage of symptomatic area on treated leaves, percentage of graft death, and percentage of apical death in seedlings 30 days after inoculation with C. tamarilloi. In addition, the enzymes peroxidase and phenylalanine ammonia lyase (PAL) had their activity quantified by their association with plant resistance to pathogens. The fungus C. eragrostidis had the best result in controlling anthracnose when applied as a preventive treatment, showing 10% less disease than the untreated plant. The same was observed for the fungus P. macrosporus when used in the curative form. These fungi also reduced the graft death. In these cases, PAL activity was higher and may be linked to the induction of resistance against the pathogen. The peroxidase activity was not expressive for treatments with saprobic fungi in the periods studied. Therefore, among the tested fungi, C. eragrostidis and P. macrosporus are promising for the control of anthracnose, deserving further studies.

Anthracnose, caused by fungi of the genus Colletotrichum, is present in the major rubber tree crop areas in Brazil, especially in São Paulo, Mato Grosso do Sul, Paraná, Minas Gerais, Espírito Santo, and northern states. This disease can affect different tissues of the rubber tree, leading to production losses. Thus, a better understanding of the pathosystem Colletotrichum x rubber tree can provide evidence to subsequent epidemiological research and phytosanitary management studies of this disease in the field. The present study aimed to investigate C.tamarilloi colonization and reproduction steps in resistant clones (IAC 502, IAC 507, RRIM 937) and in one susceptible clone (RRIM 600) of the rubber tree, verifying the influence of temperature up to 48 h after inoculation of the fungus, under 24 h wetness. Samples were analyzed under a light, a UV and a scanning electron microscope. Data indicated that the fungus had a delay in its development in resistant clones and, although colonization was expressive 48 h after inoculation, the new spore formation rate in the analyzed samples was lower in resistant clones. For RRIM 600, rapid colonization and intensive sporulation could be observed.