For 100 years bacterial spot has been causing huge losses for tomato growers worldwide. For 100 years products containing copper have held the key to controlling this devastating tomato disease. As tomato growers enter their second century of dealing with bacterial spot, the question has become whether copper applications lessen the severity of bacterial spot-or perhaps even make the disease worse. This article will discuss bacterial spot of tomato, why copper products have become less useful in the control of this important disease and finish with options for managing bacterial spot of tomato with and without copper. The first symptoms of bacterial spot one is likely to observe are small, less than 1/8 inch dark lesions on tomato leaves. The lesions may appear watersoaked, especially in the morning and are often surrounded by yellow (chlorotic) tissue. These lesions, whether found on leaves or stems, may coalesce to cause the loss[Read More…]
Dan Egel
The title of this article is pretty scary. But it isn’t entirely accurate. Pumpkins won’t really rot from the inside out. In this article, I will describe one way in which pumpkins can seem to rot from the inside out. Recently, I was asked to visit a field of pumpkins where the pumpkins were soft and rotting. Some of the pumpkins had already burst. Some were soft and when prodded, the insides flowed out. I set out to try to understand how this could happen. Although it seemed that the rotted pumpkins were healthy on the outside, upon closer examination, I found lesions of bacterial spot on the outside of affected pumpkins. More information about bacterial spot can be found in Vegetable Crops Hotline No. 586. Most lesions of bacterial spot on pumpkin are scab-like on the surface of the pumpkin (see Figure 1). Occasionally, however, such lesions will become[Read More…]
The Southwest Indiana Melon and Vegetable Growers Association will hold their technical meeting and variety trial showcase on Thursday, November 20, 2014, in the basement of the Southwest Purdue Ag Center, 4369 N. Purdue Road, Vincennes, IN.The meeting will start at 5 p.m. with a general business meeting. At 6 p.m., dinner will be served. Then at approximately 7 p.m.,the variety trial discussion will begin followed by a brief presentation by the Indiana State Department of Agriculture on Food Hubs. Any grower interested in becoming a member is invited to attend. Membership dues are $15 per year and can be paid at the meeting. If you have questions or want to RSVP, please contact Sara Hoke or Dan Egel at (812) 886-0198 or email shoke@purdue.edu. RSVP are due by November 14th.
The photos that accompany this article are of lesions caused by various diseases that occur on tomato fruit. The list includes diseases I commonly see in Indiana, so the list is not all inclusive. More information can be found on the Purdue Tomato Doctor app. I welcome any comments or questions. Bacterial spot of tomato. (Click on image for larger view) Bacterial speck of tomato. (Click on image for larger view) Bacterial canker of tomato. (Click on image for larger view) White mold of tomato. (Click on image for larger view) Late blight of tomato, which has just been reported in LaGrange County Indiana. (Click image for larger view) Blossom-end rot of tomato. This disorder is the only abiotic (non-disease) problem included in this article. (Click image for larger view)
Over the past few weeks, I have observed several watermelon fields with relatively large areas of wilted plants.There can be several reasons for such symptoms.In the article below, I will discuss late season Fusarium wilt of watermelon.In a separate article, I will discuss mature watermelon vine decline.In a separate article/blog I discussed root knot nematode.All of these diseases can cause wilt and decline of relatively large areas of cucurbits. Fusarium wilt of watermelon is often observed when the vines are just starting to touch each other within a row. Sometimes, however, Fusarium wilt of watermelon does not show up until later in the season when the plants are near maturity. Fusarium wilt at this point in the season may cause a few vines to wilt (Figure 1). The distribution of affected plants is due to the distribution of the Fusarium fungus in the soil. Often well drained areas of the[Read More…]
The low tonight is forecasted to be 28 F. In preparation, we placed clear plastic over each row. This type of plastic is not vented. Therefore, one must be very careful to watch the temperature inside the tunnel when there is direct sunlight. Although we made it through last night, tomorrow morning will be the real test! UPDATE: After the cold night of Tueday morning–the tomatoes made it through fine. However, it didn’t get as cold as predicted. We found it difficult to manage the low tunnels when the sun was out during the day. Growers should be very careful about clear plastic tunnels without vents. The tunnels can get very hot. Clear plastic low tunnels over the tomatoes in the high tunnel. Note that there are no vents. Care must be taken to vent low tunnels if necessary. This can be done by opening the ends. The ends would[Read More…]
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