Influência do parasitismo pelo nematoide de galhas nos níveis de nutrientes em folhas e na fenologia de goiabeira 'Paluma'

Abstract

The reduction in vigor of guava infected by Meloidogyne enterolobii is a consequence of changes in root system, with this infection triggering a syndrome characterized by symptoms related to nutritional imbalance. To characterize it, chemical analyses were performed in three types of leaves (leaves without symptoms, with symptoms considered mild and severe) and also in soil in two periods: February and August. The plants were grown for two years with and without inoculation of the guava nematode. The concentrations of N, P and K decreased in leaves without symptoms compared with leaves with mild and severe symptom in the analysis carried out in both seasons. Ca concentration was increased with the worsening of symptoms in both seasons. Mg concentration did not change in February, but in August it also had its highest concentration in leaves with severe symptoms different from the leaves with mild or without symptoms. Leaf S concentration was higher in leaves without symptoms in the analysis conducted in February, whereas in August, the leaves with severe symptoms had higher S concentrations. The concentration of B did not differ regarding the presence or absence of symptoms and time of analysis. In February, Cu and Fe concentrations were increased in leaves with severe symptoms. The concentration of Zn decreased with increasing the severity of leaf visual symptoms in both times of assessment. The phenology of guava cultivar Paluma was not affected by infection of M. enterolobii at the first flowering.