Answer #1 ·
Gardenality.com's Answer · Hi Linda,
Not exactly sure what the problem is. Squash bugs will cause wilting of the leaves, but not only yellowing of the tips. And so will the Squash Vine Borer. Check the under side of the leaves to see if there are larva present. Small brown egg looking capsules. If none are present the plants may be experiencing too much water or too little water. It is usually too much water that causes problems with the outer part of the leaves. If too little water you would notice wilting of the leaves.
Have you fertilized the plants? Could be lack of fertilizer. Dynamite Organic is my favorite fertilizer for Vegetable plants, or Espoma Garden Tone. Both selections are organic and very safe to use.
Could be a fungus. You might want to spray Neem Oil on the plants just to make sure that neither fungus or insects damage the plants. Neem Oil is by far the best control method for insects and fungus on vegetables. It is organic and very safe to use. Smells like fruit.
Hope this helps.
Brooks Wilson))