Pine Tolerance to Several New Herbicides
Four new chemicals and Velpar L (R) were applied at several rates to loblolly pine (Pinus taeda L.) seedlings ranging in age from approximately 1 month to 3 years. Of the chemicals applied (Oust(R) to 3 years DPX-6376, and Velpar L from DuPont. Lontrel(R) from Dow; and EL-187 from Eianco), EL-187 and velpar L caused significant pine mortality. In greenhouse studies, EL-187 killed 1 year old loblolly pine at all rates tested (l-4# ai/a). In field tests on 3 year old loblolly, 2 and 4# ai/a resulted in 100% mortality.
Velpar L applied to 1 month old and 1 year old (since planting) loblolly tubelings at 2# ai/a resulted in 46% and 1% mortality respectively.
Lontrel, Oust and DPX-6376 appear safe on pine at rates up to 2, l/4, and 1/4# ai/a respectively regardless of pine age. Oust and DPX-6376 appear safe on 1 year and older pines at rates up to 2# ai/acre. All three of the above appear safer on pine than Velpar L at effective herbicidal rates.