August 1 is the Pennsylvania deadline for petitions for independent candidates and the nominees of unqualified parties. The Green Party did not obtain the needed 16,639 signatures, according to this story. The party only has 14,000 signatures on hand.
Pennsylvania, New Hampshire, Alabama, California, and New Mexico will be the five states this year with a complete Democratic-Republican ballot monopoly for all statewide offices. Although the New Hampshire deadline is not until August 6, the Libertarian petition for U.S. Senate in that state will not succeed.
This is the third midterm year in a row in which Pennsylvania voters will not have anyone to vote for, for statewide office, except the Democratic and Republican nominees. The only other states for which this is true are New Mexico and Alabama.