The information and recommendations in this newsletter are applicable to North Carolina and may not apply in other areas.
The information and recommendations in this newsletter are applicable to North Carolina and may not apply in other areas.
From: Gerald J. Holmes, Extension Plant Pathologist and Jonathan R. Schultheis, Extension Horticulturist
We are receiving a lot of calls and samples of rotten pumpkin fruit in recent weeks. When pumpkin fruit are exposed to long periods of standing water or water-saturated soils, many will rot. Standing water will make the fruit surface less resistant to invasion by insects, fungi and bacteria or simply provide optimum conditions for these organisms to gain entrance.
Can we do anything to keep pumpkins from rotting? There are no quick fixes here. Depending on the type of rot, once it begins, it will usually progress quickly and rot the entire fruit. Once a pumpkin fruit rot starts, it cannot be cured, only prevented. Some ways to help reduce the incidence of rots are:
1. Harvest mature fruit as soon as possible to remove them from the environment that is leading to rot (i.e., the field). Pumpkins are sensitive to chilling injury at temperatures below 50 degrees F.
2. Carefully inspect fruit and leave fruit with any signs of rot in the field. A small decayed spot can quickly involve the entire fruit.
3. Avoid wounding fruit during harvest and transport. Handles are notorious for wounding fruit which can result in points of entry for decay causing fungi and bacteria. This is why stacking fruit is a bad idea. Only mature fruit should be harvested, since the surface is hardened and thus more resistant to wounding.
4. Place fruit in a cool, shaded, dry place that is protected as much as possible from the elements. The conditions at the point of fruit contact are especially important. Anything that enhances air circulation will help prevent rot. Curing pumpkins (80-85 degrees F and 75-80% relative humidity for 10 days) will also prevent postharvest decay. Optimum temperature for short-term storage and transport is 55-60 degrees F.
5. Do not wash fruit unless necessary. If washing is necessary, use a Clorox solution (10 parts water to 1 part Clorox). This will not cure existing rots, but will prevent spreading pathogens in the water.
In future years, growers should consider the following preventative measures:
1. Select fields that are well-drained, both vertically through the soil profile and horizontally through surface runoff. The key is to keep the fruit dry.
2. Select a variety that is well suited for North Carolina. No variety is bred to withstand hurricane conditions, but some do better than others under adverse conditions. We have tested approximately 40 varieties in each of the last 2 years. These data are available upon request.
3. Minimize insect and disease activity during the season by following a good pest management program (no room to elaborate on that here). Foliar diseases such as anthracnose and gummy stem blight are also important fruit rot pathogens. It is very important to have a good leafspot and blight management spray program during the growing season.
Go to http://www.agcom.purdue.edu/AgCom/Pubs/botany.htm#5 for a PDF version of "Identification & Management of Pumpkin Disease by R. Latin and K. Rane of Purdue University. This publication contains color photographs of several pumpkin fruit rots.
Employment and program opportunities are offered to all people regardless of race, color, national origin, sex, age or disability. North Carolina State University, North Carolina A&T State University, U.S. Department of Agriculture, and local governments cooperating.
Last modified on December 1, 2000 by Stephen J. Toth, Jr.