Can industrial cleaning procedures make Urochloa ruziziensis seeds nematode free?

Abstract

Seeds for agriculture should be pathogens free e.g. from plant-parasitic nematodes that if present in seed lots may be transferred to other clean areas as inoculum to infest other host plants. The aim of this work was to identify and quantify active forms of nematodes during the cleaning procedures of Urochloa ruziziensis seeds and also to evaluate its efficiency in turning the seeds nematodes free. Three seed lots with distinct origins were used. They were sampled four times in different parts of the process such as the reception and during the cleaning procedures consisting of the following treatments: unclean seeds, after using air screen cleaner, after using gravity separator (clean seeds) and the dust particles (seed covers and empty seeds). Identification and quantification of nematodes were done in each of the samples. The results showed that there is reduction in active number of Aphelenchoides and Ditylenchus nemaodes after cleaning procedures of seeds. However, this reduction does not meet the standards to be disseminated as pathogen free seeds for commercialization. The active Meloidogyne form was found only in one seed lot, but the cleaning procedures was effective to eliminate the parasites from the clean commercial seed. Others control forms need to be introduced into the system to turn pasture seed free of nematodes.