Tolerance of Selected Tree Seed to Combinations of Preemergent Herbicides

Abstract

Abstract Black locust (Robinia pseudoacacia L.), honey locust (Gleditsia triacanthos L.), and Kentucky coffee tree (Gymnocladus dioica (L.) C. Koch) seed were planted in soil treated with various combinations of preemergent herbicides and grown in the greenhouse to determine herbicide effect on seedling survival and growth. Herbicides evaluated included Lasso (alachlor) alone at 2.2 a.i. kg/ha (2.0 a.i. lb/a), and in combination with Lorox (linuron) 1. 7 (1.5), Surflan (oryzalin) 2.2 (2.0), or Dacthal (DCPA) at 11.8 (10.5); Surflan (oryzalin) alone at 2.2 (2.0) and in combination with Dacthal (DCPA) 11.8 (10.5) or Lorox (linuron) 1.7 (1.5); Dacthal (DCPA) alone at 11.8 (10.5) and in combination with Lorox (linuron) 1.7 (1.5); and Lorox (linuron) at either 1.7 (1.5) or 3.3 (3.0). All treatment were acceptable on Kentucky coffee tree seed. Lasso (alachlor) or Dacthal (DCPA) alone or mixed together and applied to honey locust or black locust were acceptable in respect to height and/or dry weight growth. All other treatments were damaging to these two species.