Mortality of seedling windbreak trees caused by a common sunflower insect Isophrictis similiella (Chambers) (Lepidoptera : Gelechiidae)

A common pest of native sunflowers (Helianthus spp.) was found to cause mor tality in seedling trees of newly planted windbreaks. Isophrictis similiell a (Chambers) (Lepidoptera: Gelechiidae) tunnels into the main stem of recen tly planted trees, causing top dieback and often mortality. Rocky Mountain juniper (Juniperus scopulorum Sarg.) and east ern redcedar (J. virginiana L .) are commonly attacked. The insect has also been found in cotoneaster (Co toneaster sp.) and potentially may attack a number of species of seedling t rees and shrubs. I. similiella larvae normally inhabit the stems and heads of sunflower, but if disturbed, as from tree planting operations, the larva e may seek out alternative shelter. Newly planted seedlings are often the o nly vegetation available.