Dan Egel

Clinical Engagement Associate Professor
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SWPAC

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​Cabbage is the crop most often affected by black rot, however, other crucifers such as broccoli, cauliflower, mustard, kohlrabi or Brussels sprouts may be affected. The first symptom one is likely to notice is a ‘V’ shaped lesion on the margin of the leaf (Figure 1). However, the symptom on Brussels sprouts observed recently are irregular, jagged lesions on leaves (Figure 2). The plants represented in Figures 1 and 2 are different varieties of Brussels sprouts. The differences may be due to differences in susceptibility of the two cultivars or the cultivar in Figure 2 may have been infected at an earlier age than the one in Figure 1. Figure 3 shows two severely affected plants next to a relatively healthy plant. Black rot is most severe in wet, warm weather. The emergence of this disease during a rather cold spring may mean that the disease started in a greenhouse situation. The bacterium that causes[Read More…]


Pith necrosis of tomato may result in dark

​This disease has been reported in two different greenhouse situations. Although the disease is not usually economically important, a brief review of the disease is offered here to help tomato growers differentiate pith necrosis from more important problems. Tomato pith necrosis causes dark brown streaks on tomato stems and leaf petioles (Figure 1).  Often stems may appear twisted and distorted. When cut open, the stem may appear discolored and chambered (Figure 2). Eventually, the affected plant may become stunted and wilt. Tomato pith necrosis is usually found in greenhouses or high tunnels. Because the plant has a discoloration in the stem, it is sometimes confused with bacterial canker, a much more serious disease. A comparison of the two diseases can be found at https://ag.purdue.edu/arp/swpap/Documents/pith-necrosis%20.pdf.  It is not clear how pith necrosis spreads or enters the tomato plant, but it is probably best to remove affected plants and avoid using pruning equipment on diseased plants. When removing[Read More…]


​​A field day will be held on July 9 to share with the public the various research activities at the Southwest Purdue Agricultural Center in Vincennes, IN. The day will start at 7:30 A.M. with a health fair. Registration starts at 8:30 A.M. Presentation topics include: managing cucumber beetles while protecting bees, production of vegetables in high tunnels, canola production, hybrid cottonwood as a bioenergy crop, grape production, field crops disease update, soybean production, maximizing seed corn investment and benefits of starter fertilizer. Lunch is free with registration. A PARP class will be offered after lunch. Please contact Barb Joyner at 812-886-0198 or joynerb@purdue.edu to RSVP or go on-line at http:///tinyurl.com/2015SWPAC.


​A field day will be held on July 9 to share with the public the various research activities at the Southwest Purdue Agricultural Center in Vincennes, IN. The day will start at 7:30 A.M. with a health fair. Registration starts at 8:30 A.M. Presentation topics include: managing cucumber beetles while protecting bees, production of vegetables in high tunnels, canola production, hybrid cottonwood as a bioenergy crop, grape production, field crops disease update, soybean production, maximizing seed corn investment and benefits of starter fertilizer. Lunch is free with registration. A PARP class will be offered after lunch. Please contact Barb Joyner at 812-886-0198 or joynerb@purdue.edu to RSVP or go on-line at http:///tinyurl.com/2015SWPAC.


This watermelon transplant has a water soaked area just under the seed leaves

Most watermelon growers are in the process of placing transplants in the field. I have received several commercial samples of transplants still in trays prior to out-planting. The two diseases I have observed so far are gummy stem blight and bacterial fruit blotch. Below, I discuss these two diseases as well as management options. Gummy stem blight on transplant seedlings may be recognized by the watersoaked area of the stem (botanical term:  hypocotyl) as shown in Figure 1. The watersoaked area may eventually turn brown and woody.  A closer look at the woody area may reveal the small, dark fungal structures of the gummy stem blight fungus (Figure 2). The true leaves of watermelon transplants may also be affected. The fungus that causes gummy stem blight (Didymella bryoniae) may survive in crop debris, thus overwintering in the field from year to year. This fungus may also survive in seed. It is also possible for the fungus to[Read More…]


​Many cantaloupe and watermelon growers have planted transplants in the field or will soon. A question many growers often have is when and how should one apply fungicides.  Applying fungicides according to a weather-based system is easy for cantaloupe and watermelon growers. MELCAST was developed at Purdue University by Rick Latin to allow growers to apply foliar fungicides to control Alternaria leaf blight, anthracnose and gummy stem blight. When MELCAST is followed, fungicides are applied when they are most needed depending on leaf moisture and temperature. Details are listed below or in the extension bulletin, Foliar Disease Control Using MELCAST, BP-67-W. Download the bulletin at www.extension.purdue.edu/extmedia/BP/BP-67-W.pdf or contact Dan Egel for a copy.  The MELCAST program uses weather information from one of the 12 sites located around Indiana: Daviess County, Decker, Elkhart County, Gibson County, Jackson County, Oaktown, Richmond, Rockville, Sullivan, SW Purdue Ag Center, Vincennes, and Wanatah. MELCAST also[Read More…]


The tomato plants shown here are stunted

​Symptoms of this disease include tomato plants with lower leaves that become yellow (chlorotic) and die; plants that begin to wilt; a lesion on the lower stem at ground level (Figures 1 and 2). If tomato plants are removed from the soil and carefully split open from the ground level, a discoloration of the vascular tissue can be observed (Figure 3). It is important to note that this discoloration does not extend up the stem more than 6 to 8 inches. If the discoloration extends up into the plant canopy, the disease may be Fusarium wilt of tomato. Although growers may observe multiple plants begin to die of this disease over a period of days or even weeks, the fungus does not splash from plant to plant.  Therefore, there should be no plant-to-plant spread in the high tunnel. Temperatures from 68 to 72°F favor Fusarium crown rot and may explain why I observed this disease last week when[Read More…]


​Since the season of applying fungicides to vegetable crops has arrived, below I have listed 10 rules that will help vegetable growers apply fungicides effectively and safely. Apply fungicides prior to the development of disease. Although many fungicides have systemic (“kick back”) action they will not completely eradicate diseases after they have started. And by the time a single disease lesion is observed in the field, many more lesions too small to observe are already working at your crop.  Most systemic fungicides move less than an inch toward the tip of the plant or may just move from the upper to the lower side of the leaf.  Use shorter spray intervals during weather conducive to plant disease. Each plant disease has its own “personality” and thus prefers different weather. However, most plant diseases require leaf wetness. Therefore, during periods of rain and heavy dews, more frequent fungicide applications are a[Read More…]


​This time of year, I receive many questions about what fungicides to apply. I get fewer questions about how to apply fungicides. Below, I will try to address how to apply fungicides. Many years ago, I was told that to successfully use fungicides on vegetables, one must use high spray pressures and hollow cone nozzles. However, I had trouble finding any research on this topic, just rumors. So, I did my own research. Dennis Nowaskie, Superintendant at the Southwest Purdue Agricultural Center (SWPAC) built a single row sprayer that could be used to vary nozzle types between flat fans and hollow cones and spray pressures from 30 to 150 PSI. We used the sprayer to conduct experiments on Alternaria leaf blight of muskmelon during three years of field tests. The fungicide we used to try to manage this disease was the contact product chlorothalonil (trade names include Agronil®, Bravo®, Echo® and Terranil®). Phillip Harmon, now[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…]