Field-cage evaluation of the parasitoid Phymastichus coffea as a natural enemy of the coffee berry borer, Hypothenemus hampei

Phymastichus coffea LaSalle (Hymenoptera: Eulophidae) is an African parasitoid that has been imported to Mexico and other Latin American countries for the biological control of the coffee berry borer, Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae: Scolytinae). As a part of the evaluation of this natural enemy in Mexico, we conducted a series of parasitoid inclusion cage experiments to evaluate parasitism rates under different parasitoid:borer ratios (1:5, 1:10, 1:15, 1:20 and 1:30) using entomological sleeves. The presence of P. coffea inside the sleeves did not affect avoid the perforation of coffee berries by the borers, but damages to berries were significantly diminished. Borers that did not enter coffee berries were more susceptible to be parasitized by P. coffea than borers that entered inside berries (i.e., borers that perforated the endosperm). The treatment resulting in the highest level of parasitism was the 1:5 parasitoid:borer ratio, which had 79% parasitism when borers where outside berries. In general, the highest percentage of parasitism occurred when the highest proportion of parasitoids was used. The 1:5 and 1:10 parasitoid:borer ratio resulted in the highest parasitism. The use of P. coffea resulted in a 2.2-3.1 fold lower coffee berry borer damage to the seeds weight, showing the beneficial effect of this natural enemy. The weight of coffee seeds significantly decreased in treatments where no parasitoids were used (control) and in treatments with the highest number of borers. All treatments that received parasitoids to control the coffee berry borer had a higher seed weight than the control. Our studies indicate that P. coffea has a strong potential to become an effective biological control agent against the coffee berry borer.