Weeds, Drought: Gourds need 1" to 1 1/2" of water per week. They need to be free of weeds, grass, etc. Mildew, Anthracnose, bacterial wilt & cucumber beetles thrive in damp weeds & grass.
Be sure to check chemical labels for cucurbits/gourds before using any chemical.
Powdery Mildew looks like talcum powder on tops and bottoms of leaves. It is carried by the wind.
Downy Mildew shows up as yellow spots on the upper surface of the leaf. When the leaf is wet you can see fungal structures underneath the spots.
Anthracnose is another fungal disease and is carried by cucumber beetles. Symptoms will include 1/4" to 1/2" spots that are usually described as "water soaked". The spots expand to rough circular brown areas that eventually crumble away. The spores can live for 2 years without a host.
If these are left untreated you can expect fewer gourds, poor quality and can even completly kill the plants. For more information on chemicals or natural ways to control these pests and other enemies contact your local Agricultural Extension Agent, local farm supply store or one of your local Master Gardeners.