67 articles tagged "Tomato".

One way insects communicate with individuals of the same species is with pheromones. Pheromones are volatile chemicals released by an insect that usually can be detected only by individuals of the same species. There are a number of different types of pheromones, but the most common type is the sex pheromone. Usually the females will emit a tiny amount of a chemical that attracts the male to her and increases the likelihood of mating. Because the chemical is volatile, air currents carry it. The male detects the pheromone in the air with receptors on his antennae. He then flies upwind to find the source of the pheromone, a prospective mate. The chemical compositions of pheromones for a number of pest species have been identified and synthetic copies can be produced in the laboratory. Synthetic pheromones can be used in conjunction with traps to catch male insects. Listed below are some, but[Read More…]


Bacterial spot of tomato is one of the most serious diseases facing tomato growers in Indiana. As described at Vegetable Diseases in Greenhouses (PDF), bacterial spot is more of a problem for field tomatoes than for greenhouse tomatoes. Symptoms and management of bacterial spot are described briefly at Bacterial Spot of Tomato and Pepper (PDF). A more detailed version of this article is found at An Update on the Use of Copper Products for Managing Bacterial Spot of Tomato (Blog Post). This article will discuss why copper products have become less useful in the control of this important disease and options for managing bacterial spot of tomato. Copper products have been used for many years to help control bacterial spot of tomato. However, some strains of the bacteria that cause this important disease are resistant to copper—that is, the bacteria have mutated to a form that is no longer sensitive to copper. Some of[Read More…]


Over the last several years, the number of questions I have had about tomato production in high tunnels has increased dramatically. Since I am a plant pathologist, most of the questions I have been asked are about diseases of tomatoes in high tunnels. However, I also have been asked production questions. One particular question about tomato product that may impact disease severity is this: how many staked tomatoes can be grown in a high tunnel effectively? To be honest, the above question is one that I often ask myself when I observe high tunnels in Indiana. It isn’t necessarily one that is asked by growers. But maybe it should be. It has been my observation that growers often try to place too many staked tomatoes in a high tunnel. The result may include diseased tomato plants due to insufficient air circulation, poor quality fruit and even reduced yields. I was[Read More…]


While visiting my son in Lincoln, Nebraska this past summer, I had the chance to browse in a second hand store.I felt myself drawn to the book section where I found a green hard cover book titled, “Yearbook of Agriculture, 1928”. From 1894 until 1992, the Department of Agriculture published a Yearbook of Agriculture annually. These books provided updates, features and statistics for the year. The reports actually go all the way back to 1862, when the head of the agriculture department, Isaac Newton, submitted a report to the Commissioner of Patents. (It turns out most of these books have been scanned and are on-line-I could have saved myself $1.50 had I known!) It is my plan to report on parts of the 1928 book that I think might interest vegetable growers in Indiana. The first subject which caught my eye were the statistics for processing tomato production. Below I[Read More…]


​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…]


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​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)


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​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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