Displacement and parasitism of entomonematodes in berries infested by the coffee berry borer Hypothenemus hampei (Coleoptera: Scolytidae)

Abstract

The use of entomopathogenic nematodes or entomonematodes (EN). is a possible alternative for the control of the coffee berry borer Hypothenemus hampei, in berries that have fallen to the soil. The texture of the soil is a limiting factor of EN persistence, displacement and host finding. In this experiment, the displacement of two EN species: Heterorhabditis bacteriophora (Rhabditida: Heterorhabditidae) and Steinernema feltiae (Rhabditida: Steinernematidae) towards coffee berries (mature and dry) was evaluated. The variables evaluated were an index of displacement (IA), and penetration into berry (IPF), variables evaluated initially in the sand. Once the berry type was selected, the effect of two soil textures, Loam clay Sandy (F.Ar.A) and loam (F) was evaluated. A rectangle of acrylic was used as an experimental unit, and 100 infective Juveniles (IJ) were placed to 5cm from the berry (mature or dry) in agreement with the treatments. The time of evaluation was 168 hours after the beginning of the experiment. In the selection of the berry, the greatest value for IA was exhibited by the dry berry and had a value of 21,13 ± 3,3% and IPF of 10,91 ± 2,2% (average ± standard error), results which show that the values differ statistically (LSD 0,05) from those obtained for the mature berry (IA: 5,63 ± 1,48%; IPF: 3,56 ± 1,06 %) independent of EN. With regards to the evaluated textures, they did not present any effect in the displacement of EN towards the dry berry, the greatest values for IA (15,73 ± 4,87%) and IPF (7,47 ± 3,51%) being obtained for H. bacteriophora in loam texture and for S. feltiae in Loam clay Sandy texture with 7,33 ± 3,51 (IA) and 4,33 ± 1, 12% (IPF) respectively. The displacement tendencies of EN, and their effect on the mortality of individuals of H. hampei in different stages of development are discussed in this paper.