Alfalfa
was flamed using the Red Dragon TD-12 LPS Alfalfa Flamer supplied by
David Rippe (Figure 3a, 3b, 3c, & 3d).
This burner used 20 gals of propane per acre traveling at four (4) miles
per hour and 26 gals of propane per acre traveling at three (3) miles
per hour. Both herbicide and insecticide treatments were applied using
an R and D CO2 assisted backpack sprayer with coverage of 20 gals/A
at 30 psi. The alfalfa field for these experiments was scouted in early
March and contained a large population of blue mustard.
Experiment
I plot sizes were 12 feet by 200 feet. Each plot was sampled three times
per assessment date using a 32-inch diameter hula-hoop (Figure
4). Weed population counts were collected 13, 22, 31, 40, 53, and
75 days after the flaming and herbicide treatments. Alfalfa height was
measured 31, 40, 53, and 75 days after the flaming and herbicide treatments
were applied (Figure 5). The weevil larvae
evaluations were performed 7, 23 and 29 days after the insecticide treatment
(54, 70, and 76 days after spring flaming). Weevil larvae from 20 stems
were randomly collected from each plot. A 10% ammonia solution was used
to extract the weevil larvae from the alfalfa stems (Figure
6).
Harvest
took place on 5/31/01 (Figure 7). Defoliation
assessment took place on 6/5/01 (Figure 8).
Experiment
II plot sizes were 12 feet by 100 feet. Weed population counts were
collected 0, 9, 19, and 42 days after the herbicide treatments (19,
37, 47, and 70 days after the spring flaming treatment). Alfalfa height
was measured 19 and 42 days after the herbicide treatments (47 and 70
days after the spring flaming treatment). The weevil larvae evaluations
took place 7, 23, and 29 days after the insecticide treatment (54, 70,
and 76 days after spring flaming). Harvest occurred on 5/31/01. Defoliation
assessment took place on 6/5/01 (Figure 8).
On May
21, 2001, Colorado State University Extension of Adams County
hosted the "Alfalfa Pest Management: On-Farm Comparison Organic
versus Conventional field day. Fifteen participants learned how to scout
alfalfa fields for weed and insect pests (Figure
9).
