Fungus gnats

the squash fruit not forming is probably lack of pollination u can hand pollinate the female flowers from the male flowers, the females will be the flowers with lil fruits behind them, u can just get a cotton swab or paint brush collect some of the pollen from the male and rub in into the center of a female flower as for the fungus gnats theres a few things u can do, most of the time they show up from overly wet soil and its the larva in the soil that needs to be controlled, u can allow the top couple inches to dry out for a few days with the lack of water the larva will die back and reduce the numbers can also add a think layer of mulch to the top of the soil this helps to prevent the newly hatched flys not be able to fly away and they die off also most larva breath through there skin so a dose of JWA in the soil will coat the larva in soap and help kill back the numbers IF u must use a store product to get rid of them mosquito bits is what iv seen lots of people on youtube using just search for the vids, i would do the mulch it has 2 main benefits for u with the squash it will help with the gnats but it will also help with soil born funguses like downy mildew and powdery mildew by preventing the soil from being splashed up onto the plants, to help with the current downy mildew remove the infected leaves then treat the plants with protectors (LAB) once a week to help prevent the spread