Our Papaya tree leaves are covered with a heavy milky substance.
This substance causing leaves to turn dark and fall off. Milky substance also getting on the fruit. What is this substance? Please Substance is in the veins of the leaves and on the fruit. The weather here has been real high heat and high humidity.
Certified GKH Gardening Expert
Without photos, I will have to take a guess. I would have to say that if it is spreading, and killing off vegetation, then you may be faced with Downy Mildew.
This article will help you to get rid of this: https://www.gardeningknowhow.com/plant-problems/disease/downy-mildew.htm
This article will help you to grow papaya: https://www.gardeningknowhow.com/edible/fruits/papaya/growing-papaya-fruit.htm