K.V McCully1, J. Walsh2, M.J. Melanson1 and J. Dennis1
Abstract: A trial to evaluate and compare metribuzin (Lexone 75DF) applied post emergent on shepody potatoes was conducted at McCains Research Farm in Florenceville, NB. Visual evaluations on crop injury, and lamb's quarters control was collected, in addition to total yields, marketable yield, % number 1 potatoes, average number of potatoes weighing more than 10 oz., and the average weight of tubers (oz.). Visually, crop tolerance appeared excellent regardless of timing or rate. Treatments contributing to marketable and total yields were not significantly different from each other but an obvious trend was evident. Any treatment which had a late post emergent metribuzin treatment applied (July 31), resulted in slightly reduced yields. No significant differences existed when examining the % #1 potatoes. Evaluation of potato size - percent of potatoes greater than 10 oz and average tuber weight (oz.) indicated that all treatments which involved the late post emergent treatment resulted in lower sizes and weights than the untreated hand weeded control and the standard metribuzin applied pre (0.56 kg/ha). The late post treatments therefore tended to reduce the probability of large, heavy potatoes, but not the % #1 potatoes or marketable and total yield. All treatments provided excellent lamb's quarters control.
1Potato & Horticulture Branch, NBDARD, Fredericton, NB E3B 5H1
2 McCain Foods Limited, Florenceville, NB