The effects of inter-crop cultivation between rows of citrus crop on spreading of Guignardia citricarpa ascospores and in the citrus black spot occurrence/Efeito de cultivos intercalares nas entrelinhas dos citros na liberacao de ascosporos de Guignardia citricarpa e na ocorrencia da mancha preta dos citros

• Published in: Revista Brasileira de fruticultura 2013-03, Vol.35 (1), p.102-111
• Main Authors: Bellotte, Jose Antonio Miranda, Kupper, Katia Cristina, Rinaldo, Davi, De Souza, Andressa, De Goes, Antonio
• Format: Article
• Language: eng ; spa
• Subjects: Arachys pintoi; Citrus sinensis; Controle Cultural; Cultural control; Cynodon dactylon; Phyllosticta citricarpa
• ISSN: 0100-2945; 1806-9967

This study highlighted the effect of planting coast-cross grass and forage peanut cv. Amarilis between rows of Natal oranges on spreading of Guignardia citricarpa ascospores and consequent citrus black spot control. Treatments evaluated were: 1--conventional cultivation, free of fungicides; 2--conventional cultivation, using protective fungicides; 3--inter-crop cultivation of coast-cross grass between rows of citrus crops and; 4--inter-cropping cultivation of forage peanut between the rows of citrus crops. Quest Volumetric Spore System™ traps were set in order to determine the number of ascospores released. A total of 33 inspections were conducted weekly, from the end of August until early September the following year. A diagrammatic scale was used to determine the severity of the disease as well as the percentage of fruits having a commercial standard. The coast-cross grass was more effective in reducing the number of ascospores produced, whose average statistics were lower than in the conventional treatments, free-fungicides. The intercrop and conventional cultivation method coupled with fungicide treatment was more effective in reducing the severity of citrus black spot symptoms, and differs statistically from the fungicide-free control method. These methods also resulted in a higher percentage of fruits of a commercial standard, ranging from the 89% through the 91% percentile, and the cultivation, free of fungicides, fell within the 73%. Index terms: Citrus sinensis; Cultural control; Phyllosticta citricarpa; Arachyspintoi; Cynodon dactylon No presente, foi avaliada a influencia do amendoim-forrageiro cv. Amarillis e da graminea coastcross nas entrelinhas de plantas de laranjeira 'Natal' quanto a producao e liberacao de ascosporos de G. citricarpa, e consequente controle da mancha-preta dos frutos citricos. Os tratamentos avaliados foram: 1-cultivo convencional, sem utilizacao de fungicidas; 2--cultivo convencional, com utilizacao de fungicidas; 3--graminea coastcross, e 4--amendoim forrageiro entre as linhas das plantas. O monitoramento de ascosporos deu-se mediante armadilhas caca-esporos do tipo Quest Volumetric Spore System™. Um total de 33 inspecoes foi realizado semanalmente, a partir do final de agosto ate inicio de setembro do ano seguinte. A quantificacao da doenca deu-se mediante utilizacao de escala diagramatica de notas, sendo tambem determinada a porcentagem de frutos com padrao comercial. A graminea coastcross foi o melhor tratamento em r