This experiment was conducted to evaluate the effects of flaming vs. chemical spraying on the population of alfalfa weevil, parasitism, weed control, yield, soil organic matter and microorganisms in an alfalfa field. The study was a randomized block design one with four treatments and three replicates, including flaming, spraying, flaming plus spraying and c1ieck, conducted during 1996-1997. Each block was 3360 M2 with 2-3 year old alfalfa in The College of Agriculture experimental field. The results revealed that flaming and flaming plus spraying caused reduced populations of alfalfa weevil larvae, while no significant difference was observed between spraying blocks and check. Larval alfalfa weevil populations were increased in all treatments at various time intervals until the first alfalfa cutting. Flaming on the other hand significantly reduced weed density and improved the quality of harvested crop. In 1997, yield in the flaming treatments was significantly higher than those in the other treatments, whereas in 1996 flaming caused reduction in yield. Flaming had no effect on alfalfa larvae parasitism by Bathyplectes spp. and did not reduce population of these beneficial insects. No differences were found in soil organic matter and the number of microorganisms in flamed and unflamed blocks.
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