Abstract As native tree species are often used for densification, enrichment and degraded areas recovery, a better understanding of the behavior of their seedlings in response to light exposure is needed. This study evaluates the growth and morphological behavior of five native forest species of the Brazilian Mixed Ombrophilous Forest under shading levels of 90%, 50%, and 0%. The species were measured for height to root collar diameter (RCD) ratio (H:D), leaf area (LA), Dickson’s quality index (DQI), and stem, leaf, and root biomass. The LA did not differ among the treatments for three species and did not differ among species in full sun. The results for H:D ratio, DQI, and biomass indicate better growth in treatments with greater light availability. The species are recommended to be used as follows: Cedro-vermelha in full sun; Tarumã-azeitona, Ingá-doce, and Ocotea-guaicá in varying environmental conditions; and Branquilho-bravo in 50% shade and full sun conditions.

RESUMO Apoharknessia eucalyptorum foi inicialmente descrita em 2017 e identificada em folhas de Eucalyptus dunnii no Sul do Brasil. No entanto, faltam informações sobre o cultivo in-vitro para estudos complementares. No presente estudo folhas de E. dunnii foram inoculadas para demonstrar a patogenicidade de A. eucalyptorum, e o crescimento e esporulação foram avaliados em temperaturas de 15, 20 e 25°C em quatro meios de cultura: extrato de malte-ágar (MEA), batata dextrose-ágar (PDA), suco V8-ágar (V8) e feijão dextrose-ágar (BEAN), sob luz constante. Apoharknessia eucalyptorum causou manchas foliares nas folhas inoculadas. As melhores condições para o crescimento micelial foram em 25°C em PDA, BEAN e MEA. Para a esporulação as melhores condições foram a 25°C em todos os meios testados, e também a 20°C em PDA e BEAN. As características das colônias mudaram com as temperaturas, em 15°C as colônias formaram micélio cotonoso, enquanto que em 25°C o micélio cresceu espalhado pelo meio de cultura formando margens escuras limitadas por micélio branco manchado e conídios. As condições indicadas para o crescimento e esporulação in-vitro de A. eucalyptorum são os meios MEA, PDA e BEAN em 25°C.

ABSTRACT Apoharknessia eucalyptorum was first described in 2017 and identified on leaves of Eucalyptus dunnii in Southern Brazil. However, information about in vitro cultivation for complementary studies is lacking. In the present study, leaves of E. dunnii were inoculated to demonstrate the pathogenicity of A. eucalyptorum, and growth and sporulation were evaluated at temperatures of 15, 20, and 25°C on four culture media: malt extract agar (MEA); potato dextrose agar (PDA); V8 juice agar (V8); and bean dextrose agar (BEAN), under constant lighting. Apoharknessia eucalyptorum caused leaf blight on the inoculated leaves. The best conditions for mycelial growth were at 25°C on PDA, BEAN and MEA. Considering sporulation, optimal conditions were 25°C for all tested media and 20°C for PDA and BEAN. Colony characteristics changed with temperature; at 15°C colonies formed a fluffy mycelium, whereas at 25°C mycelium spread across the medium forming dark margins lined by dirty-white mycelium and conidia. The conditions indicated for in vitro growth and sporulation of A. eucalyptorum are the culture media MEA, PDA and BEAN at 25°C

ABSTRACT Mycosphaerella leaf disease (MLD) is a dangerous disease for eucalypt plantations; however little information is available regarding its control using fungicides in South America. In this study, we evaluated MLD control, and growth in young stands of Eucalyptus dunnii clones (C18 and C25). After two applications of azoxystrobin + cyproconazole (0.3 L/ha-1 and 0.45 L/ha-1), with a spraying volume of 200 L/ha -1, and trifloxystrobin + tebuconazole (0.5 L/ha-1 and 0.75 L/ha -1), with a spraying volume of 100 L/ha-1, mean severity reduction for apical branches of C18 was 74%. For middle branches, application of trifloxystrobin + tebuconazole at 0.5 L/ha-1 reduced severity by 27% in C18. While fungicide applications did not affect growth in height or root collar diameter, our results suggest that the application of fungicide can deter disease progression throughout the plant. Therefore, the monitoring of disease outbreaks is crucial to enable effective, early application.