Abstract

VALENCIAGA, Nurys et al. Diversity of arthropods associated to Brachiaria spp. and damage indexes of insect-pests. Cuban J. Agric. Sci. [online]. 2015, vol.49, n.4, pp.561-565. ISSN 0864-0408.

A research was carried out in areas of Brachiaria spp., using a random block design, with five replications, in order to identify insect-pest associated to four varieties of Brachiaria: Brachiaria brizantha, Brachiaria brizantha cv. toledo, hybrid Brachiaria (Brachiaria ruziziensis x Brachiaria brizantha) cv. mulato 1 and Brachiaria decumbens cv. Basilisk, and evaluate damage indexes. Periodical random samplings were performed once a month for three years. A sample of 20 sweep/plot was taken and, according to the visual sampling, the damage caused by biting, chewing, sweep and sucking insects was determined. Results demonstrated superiority of Insecta class, with six orders, eight families and 21 identified morpho-species, in contrast to Arachnida class. The levels of provoked damage did not surpass degree two of damage scale, so it is considered as light. Basilisk variety showed less resistance to insect-pest attacks, although there was no economic damage. Species richness had a slight increase during rainy season (22), in contrast to dry season (20). Basilisk variety showed the highest number of individuals during dry season (130) and during rainy period (193). Shannon index ranged between 2.38 and 2.65. There was no associated dominant species, according to the values (0.09 to 0.12). It can be concluded the arthropods associated to Brachiaria genus, Insecta class shows higher expression, with an increase during rainy season. However, without dominance among present species, phytophagous and bioregulators, during the seasons, these species manage to live in harmony, without provoking economic damages among varieties and cultivars under study. It is recommended to continue studies on arthropod population in other varieties of Brachiaria, with other crop management

Keywords : Brachiaria spp; insect-pest; damages; diversity.

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