The effect of selected pesticides on short-root development of greenhouse-grown Pinustaeda seedlings

Abstract

Tests with 4-month-old loblolly pine (Pinustaeda L.) seedlings grown in the greenhouse show decreased short-root formation when grown in soil treated with the root-inhibiting herbicides trifluralin and napropamide. However, short-root development of treated seedlings did not differ from controls after 7 months. Percentage of bifurcate roots of 7-month-old seedlings was increased by napropamide but they were not significantly affected by trifluralin. The herbicide bifenox did not affect short-root development of 4- or 7-month-old seedlings. Percentage of bifurcate roots was increased initially with bifenox but was not affected after 7 months. The systemic fungicide triadimefon decreased both short-root development and the percentage of bifurcate roots of 7-month-old seedlings.