Biblioteca do Café
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Item Effect of temperature and photoperiod on Pseudomonas syringae pv. garcae inoculum production(Editora UFLA, 2024-11-12) Oliveira, Júlia Marques; Pozza, Edson Ampélio; Belan, Leônidas Leoni; Freitas, Marcelo Loran de Oliveira; Tedardi, Vitória MorenoBacterial halo blight (BHB), whose etiological agent is the bacterium Pseudomonas syringae pv. garcae, is one of the main diseases occurring in coffee (Coffea arabica L.) leading to losses in nurseries and fields. This study aimed to assess the effect of five temperatures (20, 25, 30, 35, and 40 °C) and three photoperiods (continuous light, 12-hour light/dark, continuous dark) on the P. syringae pv. garcae inoculum concentration and the BHB progression re sulted from this inoculum, in coffee seedlings. Using a factorial design (5 x 3) with four replicates, Petri dishes inoculated with P. syringae pv. garcae were incubated for 48 hours, and the concentrations and bacterial cell dimensions were measured. The resulting inoculum was then used to inoculate coffee seedlings at 23 ± 2 °C in one leaf pair by wounding inoculation using a multi-needle apparatus. The disease severity was assessed, and the area under the disease progress curve (AUDPC) was calculated. Significant interaction (p < 0.05) between temperature and photoperiod was observed for inoculum concentration and cell dimensions. The highest inoculum concentration (2.2 x 10⁹ CFU/ml) was recorded at 25 °C under continuous light. The largest bacterial cells (4.4 µm in length and 0.7 µm in width) resulted from temperatures of 30 °C with 12-hour light/dark. For the AUDPC of BHB, a difference (p < 0.05) was observed only between inoculum production temperatures. The highest AUDPC was recorded at 25 °C, with a gradual decline observed as the temperature increased.Item MANAGEMENT OF BACTERIAL HALO BLIGHT AND OTHER COFFEE CROP DISEASES(Sociedade Brasileira de Fitopatologia (SBF), 2021) Patricio, Flávia Rodrigues Alves; Beriam, Luis Otávio Saggion; Santos, José Maria Fernandes dos; Moraes, Arivaldo de; Rossi, Agnaldo; Reis, Joao Carlos Seixas; Almeida, Irene Maria Gatti deBacterial halo blight (BHB), caused by Pseudomonas syringae pv. garcae, has reemerged as an important disease in Brazil, especially in coffee cultivated at high altitude in the states of Minas Gerais and São Paulo. In this study we evaluated copper-based antimicrobial compounds (CBACs), the antibiotic kasugamycin and the resistant inducers acibenzolar-S-methyl (ASM) and phosphite for BHB management in four experiments carried out in coffee crops in the municipalities of Caconde and Altinópolis, São Paulo State, Brazil. Fungicides to control brown leaf spot (BLS), a disease caused by Boeremia exigua pv. coffea, were also included in two experiments, because both diseases frequently occur simultaneously. Copper oxychloride, copper hydroxide, antibiotic, and ASM mixture with copper hydroxide, and phosphite reduced BHB incidence and had no phytotoxic effects on flowers or pin-head berries. Mixtures of boscalid or pyraclostrobin with copper hydroxide were compatible and effective for the simultaneous control of BHB and BLS. In this study, we showed that August-September is the most important period to control BHB in Brazil and lasts until December, when disease incidence increases, and flowers and pin-head berries are being formed. The chemical management of BHB in this period can improve the coffee crop yield.