This paper reports experimental work with colonization of Trichogramma minutum for control of the sugarcane borer (Diatraea saccharalis) in com and cane fields in Louisiana. It is shown that colonization increases very abruptly the parasitism percentage in colonized fields of cane and corn and that the parasites spread quite promptly into adjacent fields. The average percentage of borer eggs destroyed in colonized and adjacent fields was about 28% greater than in comparable check areas for the latter portion of the season. This higher destruction of borer eggs resulted in a decided decrease in the proportion of stalks bored, joints bored and moth population produced per acre in mi11ablecane. About 6000 millable stalks per acre were saved apparently by parasite colonization. By decreasing the borer attack on cane there was found to have been an average saving of from 21 to 25 pounds of sugar per ton of cane in an average of all protected areas. The cost of colonization work averaged less than $1.00 per acre.
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