Woody plant herbicide screening techniques were evaluated to expedite the screening process and decrease amounts of herbicide active ingredient required. Rapid greenhouse screening of woody plant seedlings was performed in less than 6 months, and rapid seed screening was performed in less than 20 days. A traditional field screen, requiring 10 months from application to final evaluation, was performed for comparison and regression modeling purposes. Imazapyr and triclopyr were used as test chemicals and linear regressions were generated to predict traditional field screen results from rapid screens. Significant regressions were produced that predicted field responses of loblolly pine, sweetgum, and yellow-poplar with the use of both herbicides and either rapid screening technique. This indicated that rapid screening techniques could determine herbicide efficacy and/or species spectrum in much less time with significantly less herbicide. Rapid greenhouse screens of triclopyr produced more statistically significant regressions than those using imazapyr. Rapid seed screens could estimate species spectrum within 5 days after treatment. These results indicate that rapid greenhouse screen and rapid seed screen techniques can provide woody plant herbicide developers initial efficacy and spectrum of control data in a cost- and-time effective manner.
Nomenclature: imazapyr, triclopyr, green ash, Fraxinus pennsylvanica Marsh, loblolly pine, Pinus taeda L, sweetgum, Liquidambar styraciflua L. #3 LIQST, yellow-poplar, Liriodendron tulipfera L. # LIRTU.
Additional index words: Rapid greenhouse screen, rapid seed screen.
Abbreviations: ALS, acetolactate synthase (EC 22.214.171.124); DAT, days after treatment; WAT, weeks after treatment; YAT, year after treatment; % C Ht, percent control of height; % Nec, percent leaf necrosis; % Mort, percent mortality; P, P value for test of significance; R2, coefficient of determination; CV, coefficient of variation; µE/m2/s, microEinstein per square meter per second.