Vol. 51—1997 - NorthEastern Weed Science Society

184
TABLE 1. Mean raspberry cover (%) and height (em) in August 1990 and in August 1991
for spring and fall treatments.
Treatment
1990
mean
SE
Cover
1991
mean
SE
1990
mean
Height
std err
1991
mean
std err
CONTROL 92.3 a 4.6 91.7 a 4.7 83.9 a 9.7
SPRING:
10 % granular
1 kg ai/ha 71.4ab 15.7 77.6 a 12.7 56.9ab 14.0
2 kg ai/ha 63.9ab 9.8 65.9ab 8.7
52.3ab 6.9
4 kg ai/ha 39.1 b 14.0 32.5 b 10.9 37.2 b 12.8
5 % gram lar
2 kg ai/ha 48.0ab 11.5 65.6ab 14.1 45.8ab 12.1
liquid
2 kg ai/ha 52.4ab 7.5
43.4ab 5.1
10 % gra ular
2 kg ai/ha
liquid
2 kg ailha
54.6ab 7.6
FALL:
42.1 b 19.8
42.3 b 10.2
82.8 a 12.2
58.2 a 14.4
51.2 a 7.4
32.0 a 10.7
61.0 a 19.3
42.0 a 4.7
37.0 a 17.3
32.4 a 8.6
a-b Numbers within columns followed by the same letter are not significantly different at the
5% level, ccording to Tukey's Studentized Range (HSD) Test.
Su !Vivalof seedlings planted approximately 1 month after spring treatment was less
than controls (Table 2). Survival of seedlings planted approximately 1 yr after spring
treatment or 9 months after fall treatment was greater than that of control seedlings for most
treatments. Differences in black spruce seedling survival, attributable to formulation, were
noted duri ng earlier growing seasons. For seedlings planted 1 yr after spring treatment,
survival VI as lower for the liquid hexazinone treatment and higher for both granular (2 kg
ai/ha) trea tments during the 2nd through 4th growing seasons after planting (GSAP). No
difference in survival was observed for the two 2 kg granular treatments.
Injtial black spruce seedling stem volume did not differ significantly among treatments
(Figure 1 . Significant stem volume increases over control seedlings were first observed 2
GSAP (P = 0.022) for seedlings planted 1 yr after spring hexazinone treatments, and
continued through the 5th GSAP (P = 0.004). Significant stem volume increases over control
seedlings also were first observed 2 GSAP (P =0.002) for fall hexazinone treatments, and
also continued through the 5th GSAP (P = 0.001). Significant stem volume increases over
control Sf; edlings were first observed 3 GSAP (P =0.022) for seedlings planted 1 month after
spring he azinone treatments, and also continued through the 5th GSAP (P =0.001). Five
years afte planting, no differences in stem volume, attributable to formulation, were observed
among sI ring or fall hexazinone treatments.