We have a problem with our pumpkins, the leaves are turning yellow and then dark brown around the edges. Not all varieties are showing symptoms. The spooktacular are the worst, followed by Gold Rush. Appalacian are just starting to show yellowing,and a few of the prizewinners. So far the Cushaw, Field, Lumina, and gourds are not showing any symptoms. We have about 5 acres and have irrigated to keep moisture levels adequate. We have sprayed to control insects and have used Nova and copper as fungicides. Our next spray is scheduled for August 12 and we plan to use Cabrio then. 3 weeks prior to planting we spread 200 lbs 34-0-0, 100 lbs 0-0-60 and 100 lbs 18-46-0. Our last irrigation included 8 gal of 32% injected into the water. We injected the nitrogen because we felt we had lost some of the nitrogen due to the heavy rains we had during the first two weeks of June and this soil is very sandy. The plants have set fruit for about 3 weeks and are continuing to bloom but some that are affected worse have stopped growing and are not making new blooms. I don't know if this is a disease problem or a fertility problem. If you could help us with this we would appreciate it.

Pumpkin leaves may turn yellow due to nitrogen deficiency but plants can recover after fertigation. In this case, some plants are not recovering so it is not a mineral defieciency or water stress problem so there is a higher possibility that it is an insect pest or disease problem. If it is an insect pest problem, I suspect that you had squash vine borer problem. The larvae of squash vine borer bore into the stem close to the ground leaving brown waste at the point of entry and it destroy the stem to a point whereby water and mineral nutrients cannot be transported to the leaves leading yellowing of leaves and death of the plant. Refer to this website for more information on squash vine borer control in cucurbits page 16 (http://www.entm.purdue.edu/entomology/ext/targets/ID/IDpdf2004/Curcurbits.htm ). It may also be possible that you have soil borne disease problem such as fusarium wilt, phytophthora, rhizoctonia which can only be controlled by crop rotation. It is important to know what is causing the plants to turn yellow so my advise to you is to send plant samples to U of I Plant Disease clinic for diagnosis. The information on how to submit the samples is available in your local extension office. Let me know if you need more assistance.

Thank you,

Maurice Ogutu