Persistência de nematoides associados à rizosfera de coqueiros recém-erradicados

Abstract

In Brazil, the largest plantations and productions of coconut are concentrated along the coast of the northeastern region, which is favored by climatic conditions of tropicality. However, the coconut tree is attacked by various diseases that contribute to the low levels of production. Among the major diseases, is the red ring, a lethal disease caused by the nematode Bursaphelenchus cocophilus (Cobb, 1919) Baujard, 1989, which can be spread out by contaminated tools or through its main vector, the American palm weevil, Rhynchophorus palmarum Linnaeus , 1764. In this context, the aim of this research was to determine the persistence of nematodes associated with the rhizosphere of coconut trees newly eradicated. The coconut plantations were grown in the municipalities of Coruripe and São Miguel dos Milagres, located in the coastal region of Alagoas State, Brazil. As soon as the coconut trees, with advanced symptoms of red ring disease, were eradicated, samples of soil and roots were collected. The processing of the samples and microscopic evaluations were carried out at the laboratory of insect ecology and behavior at the Federal University of Alagoas (Lecom / UFAL). Field collections were discontinuous from the point that no longer nematodes of B. cocophilus were found in the samples. The results showed that B. cocophilus is able to survive in the roots of coconut trees, at least 118 and 133 days after cutting (DAC) in Coruripe and São Miguel dos Milagres, respectively. In both sites, occurred migration of B. cocophilus from the roots to the soil, where they are able to survive for at least 76 and 88 DAC, in environmental conditions of Coruripe and São Miguel dos Milagres, respectively. Therefore, it is necessary to maintain the area for a minimum period of 138 and 167 days after cutting, at the municipalities of Coruripe and São Miguel dos Milagres, respectively, prior to planting new seedlings, when B. cocophilus no longer are found in the roots.