Entomofauna in Leucaena leucocephala (Lam.) de Wit associated with pasture grasses: Characterization of the insect community in leucaena-Panicum maximum Jacq.

 


Osmel Alonso Amaro
Estación Experimental de Pastos y Forrajes Indio Hatuey Central España Republicana 44280, Matanzas, Cuba

 

ABSTRACT
In order to determine the taxonomic composition of the entomofauna present in associations of Leucaena leucocephala (Lam.) de Wit and Panicum maximum Jacq., and other pasture grasses, as well as the trophic structure and the diversity of the insect community in leucaena-Guinea grass, different livestock production systems located in the Pastures and Forages Research Station “Indio Hatuey” and in four livestock production enterprises of Matanzas and Havana were sampled. The results indicated the existence of a varied entomofauna, constituted by 148 species which are associated to leucaena; from them 121 constitute new records for the country in this forage plant, the report of Ithome lassula Hodges as new species for Cuba standing out, in addition to 147 new records for the legume in the neotropical region. A similar percentage of phytophagous (56 and 57 %) and beneficial insects (44 and 43 %) was found in the tree as well as the herbaceous stratum in the sampled areas with leucaena and Guinea grass during the three years of evaluation; Heteropsylla cubana Crawford was ratified as the most frequent and abundant phytophagous insect of leucaena, and the following insects were found as frequent: Doru taeniatum (Dohrn), Zelus longipes (Linnaeus) and Conocephalus fasciatus (De Geer), whose detection was important because of their condition as bioregulator. I. lassula and Loxa viridis (Palisot de Beauvois) showed potentials as noxious insects of leucaena, because it was estimated that the losses in seed production could be 71 % for I. lassula and 26 % for Erwinia carotovora subsp. odorifera Gallois, Samson, Ageron and Grimont, bacterial species identified for the first time in leucaena, whose relation with L. viridis is determinant given by the transmitter condition of this insect. The ecological indexes showed that there is high diversity of insects, with a wide representation of bioregulators, which partly explains no high populations of noxious organisms appeared in this legume. Finally, the results obtained in the diversity studies allow a better understanding of the composition, structure and functioning of the insect community present in the evaluated association of leucaena and Guinea grass, from which different strategies to be followed can be planned to adequately guarantee the phytosanitary management of this association.