Wheat burning?

I was wondering, why would a farmer burn his wheat fields when something as common (common in India anyway) as locusts attacked the wheat? Was there no pesticide at that time? True, the scene was more powerful with the use of fire, but not too realistic. I keep watching that scene all the time regardless.

[I cannot believe all the low ratings ppl give this movie. True, love for natural beauty is not for everyone, and hell, I am no nature lover either, but even if we discount the cinematography, the story itself stands high on its own. Some people said there was no story, others said it took them multiple viewings to understand the film, and yet others call this film 'boring'. I really don't get these arguments. I wish more ppl wud understand it. For me Badlands held no appeal other than Sheen's performance, but this film ranks among my favs]