Many entomologists say that campaigns to eradicate the fire ant in the United States have failed because the chemicals that were used were effective only in wiping out the ant’s natural enemies, thus making it easier for the ant to spread.
campaigns to eradicate the the fire ant in the LACE>United StatesLACE> have failed because the chemicals that were used were effective only in wiping out the ant’s natural enemies, thus making it easier for the ant to spread.
抛开主句(say that...)不谈,把以上结构提出来,主谓宾很清楚了,because是上面这个句子的原因状语句子,thus V.ing结构是这个原因从句的状语部分,表示这个原因造成的后果。I don't think there is any redundancy. Thanks.