Abstract

GIL P, ZULMA NANCY; BUSTILLO P, ALEX E; GOMEZ, DINA ESTELA  and  M, PATRICIA MARIN. Corthylus n. sp. (Coleoptera: Scolytidae ), pest of alder in rio Blanco basin of Colombia . Rev. Colomb. Entomol. [online]. 2004, vol.30, n.2, pp.171-178. ISSN 0120-0488.

In alder, Alnus acuminata HBK, plantations of the no Blanco basin, near Manizales, Caldas, the attack of an insect that bores into the trunk and branches of these trees was recently detected. The insect makes holes and galleries especially in the trunk. This damage is associated with ambrosia fungi that cause wood rot and death of the tree. This work describes the biological stages, the damage, and the fungi associated with the borer especially after examination of trees with dry branches and poor follage. Isolation of the fungus was made with samples obtained from the interior of the galleries and from lesions on the tree, including pathogenicity tests in the greenhouse. The insect was identify by Dr. Stephen L. Wood identify as a new species of Corthylus (Coleoptera: Scolytidae ). The fungi associated with the interior of the galleries were identifico as Fusarium solani, Fusarium sp., Verticillium sp. and a yeast similar to Pichia sp. Fusarium solani and Ceratocystis sp. were found in the lesion caused by the insect. Results showed that Corthylus n. sp., has a symbiotic association with several ambrosia fungi and one yeast. These fungi and yeast make the wood available to the insect, and this allows invasion of these organisms, finally causing the death of the tree. Additionally, the insect contributes to the dispersal of the fungi in the alder plantations. The pathogenicity tests with Ceratocystis sp., F. solani, and Fusarium sp., using trees of five months and four years old, were positive, showing establishment and progression of the lesion in the inoculated stem, reproducing the same symptoms observed in the field.

Keywords : Alnus acuminata; Ambrosia fungi; Ceratocystis; Fusarium .

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