Lygus Bugs as Agents of Growth Disorders in Permethrin-Treated Pine Seedling in Regeneration Areas

1992

S. 191-200

15 Lit. Ang.

Unselbständiges Werk

200040892

The ability of Lygus bugs to cause growth disorders in permethrin-treated pine seedlings after planting was studied experimentally in two regeneration areas. There were three treatments: exposure of the seedlings to Lygus, mechanical protection of the seedlings from insects, and control seedlings. There were no significant differences in the rate of growth disorders between the treatments. The permethrin application protected the seedlings against Lygus bugs in the early summer, as well as when the bug abundance was low. The development of these seedlings, as well as the multiple- leadered and bushy seedlings on a third regeneration area, was followed for two years. Multiple leadering reduced height growth and bud number, but caused marked losses in growth only when the seedlings were still multiple leadered the following year, or when they formed several, equally developed stems.