Wood Boring Insect Infestations in Relation to Mesquite Control Practices

Abstract

Wood boring insect activity in mesquite wood is of interest to fire ecologists because infested trees are much easier to burn down than uninfested trees. Wood borer tunnelling in mesquite killed by six different methods was compared over a 2-year period. Basal spraying with diesel oil + 2,4,5-T and girdling resulted in significantly more tunnelling by wood borers. Borer activity was intermediate in trees killed by basal spraying with diesel, and by burning; slight in felled trees (simulated chaining or root-plowing); and insignificant in trees top-killed by 2,4,5-T spray and in the control. Ranchers planning to use prescribed burning as a method of removing dead mesquite stems from rangeland previously treated with conventional mesquite control practices could expect a high degree of wood borer activity, and hence a greater burndown in pastures where trees have been killed in previous years by basal spraying with diesel oil + 2,4,5-T. Wood borer activity will be substantial for good burndown in trees top-killed by basal treatment with diesel oil and by burning.