Veggie Extras

The articles posted here represent subjects that may be more in-depth or descriptive than those articles posted regularly in the Vegetable Crops Hotline.

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Daikon radish is a member of Brassica family. It forms a large white tap root like a giant carrot. The tap root (12 to 20 inches long and 2 to 4 inches in diameter) penetrates into the soil leaving 2 to 6 inches protruding above ground.  Radishes are cool-season crops. They are best grown with air temperatures in the range of 50 to 65°F. They grow fast, forming a dense canopy in the fall.  They are winter killed when temperatures drop to low 20s °F for a few consecutive nights. Daikon radish is a common and popular vegetable consumed in the southeast and Eastern Asia (Figure 1). The large and white roots have a favorable mild flavor, very low calorie content and rich in vitamin C. Fresh or picked diced daikon roots are important ingredients in a variety of dishes and soups in Asia cooking. Leaves are also consumed as[Read More…]


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As Thanksgiving approaches, I have noticed that the gourds I set out before Halloween are starting to rot. But before I throw them away, what is causing the lesions? The circular lesions that can be seen in Figure 1 and 2 are symptoms of anthracnose of gourd.   That is, the pathogen that is causing the lesions in the accompanying figures is Colletotrichum orbiculare.   This is the same pathogen as the one that causes anthracnose on other cucurbits such as watermelon. (It is possible that the anthracnose is caused by a different species of Colletotrichum. Even if the pathogen is C. orbiculare, I am not sure of the race. More research would be required.)     A second question is how the pathogen contacted the gourd sitting in a basket in my house since early October.   This is a harder question to answer.   My guess is that the pathogen contacted[Read More…]


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I probably spend too much time posting photos of diseased vegetables on-line and presenting vegetable disease symptoms in presentations.   My excuse is that recognizing the symptoms of what might be a disease seems important to me.   However, it might be just as important to recognize symptoms that are not of an infectious disease. See below for some photos of leaves that do not have an infectious disease.   The leaf in Figure 1 is a relatively old leaf.   Older leaves tend to turn yellow with age.   One reason for this is that nitrogen is mobile in the plant.  When newer leaves are formed and need nitrogen, it can be pulled from the older leaf.   This means the older leaf looks yellow and perhaps brown around the edges. It is possible that non infectious problems can be important problems.   However, none of the leaves here have symptoms of a problem[Read More…]


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Driving across IN now, it is not uncommon to see many recently built high tunnels standing along the roadsides. These structures have become an important tool for farmers to extend production seasons of vegetable and fruit crops. Compared with traditional greenhouses, high tunnel demand much less energy as they are heated by solar energy and ventilated through natural air circulation. Similar to high tunnels, Chinese-style solar greenhouse is an important tool for season extension in specialty crop production in China. The structures are facing south, featured by supporting north walls (Figure 1 and 2). The north walls are essential in maintaining temperatures inside the structure. They are made up with materials having good insulation properties and with a thickness more than 30 inches. The south sides are arch-shaped, supported by steels and covered with polyethylene or polyvinyl chloride films. From north to south, the structures span 26-46 feet. A short[Read More…]


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Recently I observed lesions of leaf mold of tomato in our high tunnel at the Southwest Purdue Ag Center.  I thought I would share these photos since the lesions can be variable.   More information about this disease can be found at here.


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We recently published an article in the Hotline about gray mold of tomato.  That article and more details about this disease can be found here. In this short note, we want to share examples of the relationship of gray mold and tomato plant injury. In the figure 1 above, a pruning injury of tomato in a commercial greenhouse has become necrotic and a gray mold infection is starting. Figure 2 is from our research high tunnel.  In the photo, one can see where there was an abrasion, probably due to tying the plant in the greenhouse. This injury allowed the gray mold fungus to begin to grow.  Not only will this infection cause a die-back, but the spores produced may cause the disease to spread.  We clipped off this branch to stop the spread of the disease. The photo is taken outside of the greenhouse for better lighting. The lesson here is[Read More…]


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White mold of watermelon – Usually when I write about a vegetable disease it is because the disease may cause important economic loss. Once in a while, however, a disease I find is more a curiosity than a real problem. So, go ahead and read this article about white mold of watermelon. But please don’t worry about this disease. Simply, watch for these symptoms and let me know if you have questions. Readers may have heard me ‘talk’ about white mold of tomatoes. The fungus that causes white mold, Sclerotinia sclerotiorum, has a wide host range. Important hosts include bean, cabbage, potato, lettuce and sunflower in addition to tomato. More about the disease on tomato can be found here. If you have never heard me talk about white mold of watermelon, don’t feel left out. I don’t talk about white mold of watermelon since I have only observed the disease twice in 21[Read More…]


​ Last year at the Southwest Purdue Agricultural Center (SWPAC) we conducted a tomato high tunnel trial described here. In this article, I would like to talk about the trial we will conduct in 2015, a repeat of the 2014 trial. In particular, I would like to talk about what we have done for fertility. Before deciding on a fertility scheme, it is critical to conduct a soil test each year. Our soil test from November 2014 showed that our high tunnels were low in sulfur, boron and moderately low in zinc. In fact, plant tissue tests conducted during the 2014 season were low for both sulfur and boron. As a result of these tissue tests, we added a 10% liquid boron product and ammonium thiosulfate (7%) to the fertigation during the 2014 season. However, the next set of tissue tests carried out during the 2014 season also came back[Read More…]


In December 2014, I described the ‘Yearbook of Agriculture, 1928”. In that blog, I wrote about processing tomato production in 1925 and 2013 (the ‘Yearbook of Agriculture, 1928’ lists data back to 1925). Today, I would like to discuss cantaloupe and watermelon production. Unfortunately, yields posted in the “Yearbook” are in different units than in use today. However, I can compare acreage in 1925 and 2015. Cantaloupe production in Indiana in 2013 was at 2,100 acres. This compares to 4,820 acres in 1925. Part of the reason for the drop in acres might be that cantaloupe requires a lot of postharvest handling. Buyers want cantaloupe, also known as muskmelon, to be washed and cooled. Food safety concerns require growers to invest in specialized equipment and wade through reams of regulations. In 1925, Indiana was number 6 in the US in cantaloupe acreage, behind California and Arizona (of course) as well[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…]


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