Flaming
dormant alfalfa when blue mustard was a quarter to half-dollar size
reduced weed density significantly when compared to the untreated check.
Increasing the burn time (3 miles per hour tractor speed versus 4 miles
per hour) increased weed control levels. Pursuit control of blue mustard
was best when applied in March to quarter to half-dollar diameter sized
mustard plants rather than in April when mustard plants were 3 to 4
inches in diameter.
Flamed
alfalfa treatments shortened alfalfa stem length when compared to any
treatments that contained Baythroid early in the season. The stem length
in the flamed alfalfa treatment was not significantly different when
compared to the untreated check in Experiment I and Experiment II, 75
days after flaming.
Early
weevil larvae assessments (7 days after insecticide treatment and 54
days after flaming) showed significant activity of flaming on weevil
larvae populations in both Experiment I and II. This reduction in weevil
larvae populations was comparable to any treatment containing Baythroid.
However, flamed alfalfa treatments revealed a significant decline in
alfalfa weevil control at 23 and 29 days after insecticide treatment
(70 and 76 days after flaming).
Alfalfa
yield evaluations of both experiments revealed that no significant differences
between any treatments and the untreated check. No significant differences
were observed when relative feed values were compared among treatments.
There were significant differences in the defoliation assessment between
treatments. Any treatment containing Baythroid had significantly less
defoliation than the spring flamed treatment and the untreated check.
The spring flaming treatment had significantly less defoliation than
the untreated check.
The addition
of 10 gallons per acre of phosphate fertilizer (10-34-0) with the herbicide
Pursuit treatment increased soil phosphorous levels by 25% compared
to the untreated check. Phyto-toxicity assessments at 6 days and 9 days
after the herbicide treatment found that the tank-mix of phosphate fertilizer
(10-34-0) and Pursuit showed significant leaf injury of 4.6% and 6.7%
respectively compared to the untreated check.
Based
on environmental and pest population conditions experienced at this
location, the weevil larvae had greater impact on alfalfa quality than
the weed populations encountered in these two studies. The spring flaming
did have significant impact on both alfalfa weevil larvae and blue mustard
populations early in the season.
The Propane
Education Research Council made funding for this project possible.
Special
thanks to George Cronk, Dan Bowen, David Rippe, and Mary Edna and Alfalfa
Yield Evaluation Lonnie Chase for their assistance and support in making
this project successful.
