Pineus strobi Hartig (HEMIPTERA: ADELGIDAE)INFESTATION IN A RESTORATION WITH TWO PINE SPECIES

Abstract

Invertebrate herbivory is known to be a limiting factor for plant survival under restoration conditions but there are few studies that have dealt with the topic. In a 4-year-old restoration experiment in Michoacan, México, pine trees were growing healthy until 2006 when they were heavily attacked by Pineus strobi  (Hemiptera: Adelgidae) therefore it was decided that the effect of the adelgid on the performance of the pines: P. pseudostrobus  and P. montezumae  must be assessed. P. strobi  was eliminated in half of the trees using the insecticide Decis and assessed insect infestation and tree performance monthly throughout the 2007 growing season. The insecticide decreased P. strobi  infestation in P. montezumae  but not in P. psedostrobus . Insecticide application was not beneficial for tree growth in any species, on the contrary tree performance diminished in P. montezumae. Pinus pseudostrobus  was not harmed by insect feeding and individuals of P. montezumae  infested by P. strobi  showed greater growth than controls. P. strobi  infestation for both species seems to be of little relevance since trees did not reduce their growth.