"they say" that you should. But I never do. "They say" that allowing suckers draws strength from the main stalk, affecting ear size/set. I leave them, thinking that the extra foliage produces more nutrition, not less. It would be interesting to do a side by side study, with one group suckered, and the other group not, and compare harvest. Same with tomatoes. I am more likely to sucker my tomatoes. We have a short growing season, and keeping the plant more open hastens ripening IMO.Question: do you cut/pull the sucker plants/sprouts on corn or leave them?