Armstrong Research and Demonstration Farm
There are at least three major species differences among the pumpkins and winter squashes. And, their response to herbicides differ, so it is important to know which types are sensitive to a particular herbicide to avoid crop injury. The major jack o’lantern pumpkin belongs to Cucurbita pepo (as does summer squash, acorn squash, and gourds), butternut wintersquash is a member of C. moschata, and the buttercups and hubbards belong to C. maxima. The primary preemergence herbicides used are Curbit, Command, Sandea, and Strategy. Curbit and Command control a number of broadleaves and grasses, and Sandea has both pre and postemergence activity on many broadleaves. Strategy, a premix of Curbit and Command, is labeled for all the vine crops, including jack-o-lanterns. All of the vine crops are somewhat sensitive to Sandea, so careful use is recommended. Squash in the C. maxima species tend to be more sensitive to Sandea than other types.
Iowa State University
Taber, Henry G. and Havlovic, Bernard J., "Pumpkin and Winter Squash Weed Control" (2010). Iowa State Research Farm Progress Reports. 310.