Flame
treatments occurred when the stinging nettle, scouringrush and poison
hemlock were 1 to 4 inches tall. All weed species plant densities
averaged about 5 plants per square foot. Each plot was 16 square feet
and required 60 seconds of flaming to treat all weeds during the first
treatment and 45 seconds for all subsequent treatments. Successful
flaming requires only a blanching of weed tissue without reaching
the fire point (the temperature at which the flame becomes self-sustained).
Two days after the first flame application, 73.75% control of nettle
and 87.5% control of hemlock were achieved. Five days after the second
application of flame revealed an average of 80% control of nettle
and hemlock. Nine days after the third flame application, 87.5% control
of nettle, 99.5% control of hemlock and 87.5% control of scouringrush
were observed. Nine days after the fourth and final flame application,
97.25% control of nettle, 100% control of hemlock and 97.5% control
of scouringrush was achieved. Twenty-five days following the fourth
and final flame application, 93.75% control of nettle, 100% control
of hemlock and 85% control of scouringrush was observed.
