My general inclination after less than 30 seconds looking at your pictures is that bacteria carrying bugs have started an infection. There are of course different bacteria, but you should soon seen a reduction in flower which will deform the fruit tips because those curcubit type plants segment their seed production in a fruiting body to ensure at least some progeny. You may also see that the plant itself is segmented in a similiar defense, and you might actually rescue the forwardmost growth and repot it elsewhere to enjoy further production. Be harsh in the truncation of the body of the stem as bringing the infection with the plant into a new soil is terminal.
Bacterial wilt is a catchall name for the direction that plant seems to be headed, but that is not to say it is not a virus or even fungal. Like ourselves, a lot of things eat squash.