Morphophysiological and molecular characterization of entomopatogenic fungi associated with Hypothenemus hampei in coffee areas of the Ngäbe-Buglè region

Abstract

The coffee berry borer, Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae: Scolytinae) is a monophagous specie of coffee berries (Coffea spp.) and is one of the main pests of this crop in the Ngäbe-Buglè Region. The use of native natural enemies is one of the alternatives for managing this pest, because of that the objective of this study was to characterize morphologically, physiologically, and molecularly, isolated entomopathogenic fungi collected in coffee plantations of the Ngäbe-Buglè Region, to select those with potential, for inclusion in agroecological pest management programs. The molecular characterization of the isolates was performed by sequencing the ITS (Internal Transcribed Spacer) region (ITS 1 and 2 including 5.8 S) and comparison with the database GenBank. Twelve isolates were determined as belonging to Beauveria bassiana (Vullevein), and one isolate as Purpureocillium lilacinum (Thom) Luangsa-ard, Hou- braken, Hywel-Jones & Samson. Additionally, an Isaria javanica isolate (=Cordyceps javanica (Frieder. & Bally) Samson & Hywel-Jones)) from the entomopathogenic fungi collection of the Entomology Laboratory of IDIAP, David, was included for determination of morphological characteristics. Mortality and median lethal time were evaluated. The highest mortality rates, at day 15 after inoculation, were observed with RS-Ij006 and D-Bb1400 isolates with 100 %; followed by D-Bb1398 with 98.90 % and D-Bb1350) with 93.3 %. The least mean lethal times (TL₅₀) were obtained with the isolates of D-1388 (Purpureocillium lilacinum) with 3.52 days and RS-Ij006 with 3.98 days followed by D-Bb1350 with 6.58 days. The isolates in which the insect presented lower susceptibility were D-1391; D-1399; D-Bb1397; D-Bb1412; D-Bb1395, D-Bb1392 these needed more time to reach 100 % adult mortality of H. hampei and the TL₅₀ was greater than 11 days.