Looks like typical vine fungus. High humidity, lack of ground cover, too much fertilizer or low plant resistance can cause it. Best thing to do is to spray it with a mix of cinnamon oil, lemongrass oil, thyme oil and vegetable soap (in water). Depending on how resistant your strain is it will probably recover, but probably won't give you anything competition-worthy. That's nothing certain though, I've seen vines that looked dead continue to grow and produce fruit anyway.