Matthew Debacco has created an excellent guide with pictures to help identify pumpkin plant problems. I have posted his guide here: Pumpkin diseases and plant problems
Information about pumpkin diseases can be found here:
Pumpkin Disease Information
Additional Pumpkin Disease Information
Insects that do damage:
The cucumber beetle is my number one enemy each year. You can find information about this insect and how to control it here:
http://vegetablemdonline.ppath.cornell.edu/factsheets/Cucurbit_Beetles.htm
http://www.attra.org/attra-pub/cucumberbeetle.html
http://www.bhg.com/gardening/pests/insects-diseases-weeds/stop-cucumber-beetles/
Information about the vine borer can be found here:
Hi i have planted pumpkins 3 times now from seeds in pumpkins that i bought and used and the first time the crop was good last year and this year the leaves look healthy etc but the actual pumpkins go yellow and soft then rot while they are still small, not sure why, i was told by someone that i needed to mix sulpher (I Think) in water and water the roots only is this correct can you please help, Thanks Angela
There could be numerous things taking place that is causing your pumpkins to abort. I have also heard too much Nitrogen will cause pumpkins to abort as well. Can you provide a little more information? Have you sent a soil sample off to a reputable lab?