Isolation and pathogenicity of fungi associated to ambrosia borer ( Euplatypus segnis) found injuring pecan ( Carya illinoensis) wood

Abstract

Euplatypus segnis is an insect pest of economic importance in pecan (Carya illinoensis) trees grown at Parras, General Cepeda and Torreón Coahuila, Mexico. The objectives in this study-were to identify the fungal strains associated to ambrosia borer body and diseased pecan wood and determine their pathogenicity. The results showed that the associated fungi to Euplatypus segnis and damaging the pecan wood were identified as: Helminthosporium sp., Aspergillus sp., Penicillium sp., Phoma sp., Ascochyta sp., Phaecylomices sp., Umbeliopsis sp., Torula sp., Fusarium solani, Alternaria alternata, Fusarum oxysporum, and Lasiodiplodia theobromae. The pathogenicity tests on healthy 3 year old pecan trees cv. western using Fusarium oxysporum, Fusarium solani, Alternaria alternata and Lasio-diplodia theobromae suspension conidia shown die back tree branches after 84 days inoculation. The insect in combination with the fungal invasion eventually cause the death of trees. Additionally , the insect contributes to the spread of fungi in pecan nut orchards.