Straw is stupidly OP on day one. Any patches of wild corn were vacuumed on sight by whoever found them first, leaving their groups with 1-2 weeks advantage over everyone else (given how wwws either didn't spawn outright initially, or had their detection requirements raised substantially) .
String grass is close second. Although I guess since its benefit wasn't as obvious, it did last for much longer --- certainly not going to be the case next world, if the mechanic remains unchanged.
Did this game really need another mechanic to give massive advantage to veteran groups (favoring larger groups) from the very start? Also seems like a lot of wasted effort for something that effectively didn't outlive the first week since start.