Pumpkin and squash mildew kills plants.

Powdery mildew, a common problem of roses, turfgrass and many other plants, also is a problem for squash and pumpkin especially when we experience the cool, humid conditions of fall.

This fungal disease destroys the photosynthetic ability of the leaves reducing the quality, size and yield of the fruit. 

The first syptoms you will see are white spots on the leaves.  These spots increase and eventually cover the leaf. This disease reduces the sugars and starches necessary for the development and sizing of the fruit.

Controlling this disease is quite easy if you use the correct product or combination of materials.  Some people use SunLite oil in combination with baking soda as a spray.  A better product to use is potassium bicarbonate.  Baking soda can damage plant cells; potassium bicarbonate is much softer in its activity.  Neem oil is also reported to be an effective control of powdery mildew.  Your local nursery or garden center should have one of these products on their shelves.

These products are best applied in the evening as they remain in the liquid state for a longer period of time.  If a rain occurs shortly after you make the application you will most likely need to reapply the product.  You will still see spots on the leaves even after you treat for this disease, but as long as the spots don't enlarge or more spots don't develop, the infection has been stopped.  Follow the label to ensure you apply these at the proper dilution and frequency.

When should you harvest pumpkins and winter squash?

I  recently harvested two pumpkins. Neither was completely orange but I could not puncture the skin with a finger nail, the stage at which they are ready to harvest. Instead of leaving these pumpkins I cut them off the vine and put them on my back stoop. They continued to ripen and are now uniformly orange.

If you leave pumpkins and winter squash on the vine even though they are ready to harvest, you run the risk of them being damaged by insects or vandals.

Harvest your pumpkins and winter squash as soon as they are ready. If you can cut their rind with a finger nail they are not ready to harvest; when the rind can no longer be cut with a finger nail they need to be harvested.

Always leave a portion of the stem attached to the fruit.  Otherwise you run the risk of a disease organism invading the fruit causing rot.