ABSTRACT
Tylenchulus semipenetrans is the main nematode affecting citrus; it is widespread among Brazilian citrus orchards, causing losses that range from 10 to 30%. The aim of this study was to investigate the behavior of T. semipenetrans in a 14-year-old orchard of ‘Pera Rio’ orange grafted onto ‘Rangpur’ lime, determining its population dynamics and correlating production with the population levels of this nematode. Samples were taken at the end of each weather station, in two periods: from September 2011 to June 2012 and from March to December 2013, at a depth of 0-30 cm, from 10 plants without symptoms, 10 with symptoms and their adjacent plants, totaling 60 plants. The nematodes present in the soil were extracted based on flotation method in a centrifuge, while those in the roots, based on blender technique and centrifugation. In the 2012/2013 harvest, the fruits of each plant were collected and weighed. The number of nematodes in the soil and in the roots were plotted on graphs and correlated with temperature and precipitation data according to Pearson’s analysis, while data of fruit weight per plant and number of nematodes in the soil and roots, in each period, were transformed and subjected to Spearman’s correlation analysis (P-0.05). The largest population level of T. semipenetrans occurred in late winter and the lowest one in late spring, and it was most commonly found in roots. Temperatures in the range of 20°C are favorable for better development of T. semipenetrans.
Keywords
citrus nematodes; Citrus sinensis; population dynamics; production
