91 articles tagged "Cucurbits".

Figure 3. A Japanese type cucumber grown in a high tunnel.

Cucumbers are produced with very different production systems. The ideal cucumber variety for process pickling production is not the variety used for greenhouse production. Choosing the suitable variety for a specific production system then becomes important. Where do you find recommended cucumber varieties for high tunnel production in seed catalogs? Some of the seed catalogs have a category called Greenhouse or Protected culture. Varieties listed in this category are recommend for greenhouse or high tunnel production. Other seeds catalogs may call this group Parthenocarpic hybrid or European slicer. Cucumbers listed under these names are also suitable for greenhouse or high tunnel production. A few technical words (parthenocarpic, monoecious, gynoecious) occur frequently in the descriptions of high tunnel-grown cucumbers. Understanding their meaning is important in choosing the right varieties. Parthenocarpic means that the plant can set fruit without pollination. Since pollinators are not required in this case, parthenocarpic is a desirable characteristic for cucumbers grown in protected[Read More…]

Figure 1. Watermelon variety trial at Southwest Purdue Ag Center.

Seedless watermelon variety trials have been conducted at the Southwest Purdue Agricultural Center in Vincennes, IN for more than 20 years. In 2017, we evaluated the performance of 37 standard size seedless watermelon varieties and 4 mini watermelon varieties. This article introduces the top performing varieties in our trial in 2017. Standard size seedless watermelons Red Amber. This is a new variety. It had the highest yield among 37 varieties in 2017. Rind pattern of the variety is a medium green background with a medium dark crimson stripe. Average fruit weight in our trial was 16 lb. Red Amber had relatively firmer flesh compared with other varieties. 9651 and 9601. Both 9651 and 9601 are sugar baby type watermelons that have solid green rinds. Fruit shape is round to oval. Both varieties had a high yield in 2017, especially 9651. Average fruit size of 9651 was 16 lb and 9601[Read More…]

he round lesions on this watermelon are caused by Phytophthora blight. Note that the Phytophtora blight fungus can be seen sporulating on the lesion under moist conditions.

This disease was a serious problem in much of the state this past summer.  As a result, I have had many questions about managing this disease.  The questions I have been asked have ranged from what do I spray to how does this disease work? Therefore, I have written an article about the symptoms, biology and management of Phytophthora blight. I will concentrate on Phytophthora blight of cucurbits, but this disease is also a very serious problem on peppers. In the following article, I will outline some of the information I think it is important to know about this important disease. Phytophthora blight-biology Phytophthora blight is caused by a fungus-like organism known as Phytophthora capsici. Even when I was in graduate school in the 1980’s, my professors told us that we would discuss Phytophthora and related organisms in our fungus taxonomy class even though these organisms are more closely related to brown[Read More…]

Consumers love cucumbers that are sweet, seedless and have thin skins. They are willing to pay high prices for the long or mini cucumbers sold at grocery stores. These cucumbers are often grown in greenhouses and shipped long distances. It will attract consumers’ attention if greenhouse type cucumbers can be produced locally in high tunnels, and be available in the early-season’s market. There are at least three benefits for targeting early-season cucumber production. First, prices are higher; second, there are less pest problems; and third, things are going slower in early seasons compared to in the summer. However, we all know that cucumbers love high temperatures and do not grow well when soil temperature is low, even in high tunnels. This is especially true for the greenhouse type cucumbers. The situation may be changed with the use of grafting technology. Using squash as rootstocks, we were able to harvest cucumbers[Read More…]

In the past season, we tested performances of eight specialty melons grown under high tunnel, greenhouse, hydroponic, and conventional field systems. The melon varieties we have tested in our trials include Lilliput, Inspire, Sugar Cube, French Orange, Tasty Bites, Escorial, Savor, and Artemis. Many of these melon varieties are Charentais (Cucumis melo var. cantalupensis). A specialty melon type with an outstanding fragrant smell. If you are wondering how to grow these specialty melons, please follow us at the Indiana Hort Congress. We will present what we have learned about growing these specialty melons under different production systems.

Earlier in August, downy mildew was reported on all cucurbit species in LaPorte County in northwest Indiana and on pumpkins in Starke County (just south of La Porte County). More recently, downy mildew was reported on cucumbers and butternut squash in Knox County in southwestern Indiana. In addition, downy mildew is strongly suspected on cucumbers in Jefferson County. Growers in nearby areas should take care to manage downy mildew if they have valuable cucurbit crops. However, this late in the season, it is unlikely that there will be widespread losses. Management of downy mildew of cucurbits is discussed in the Midwest Vegetable Production Guide for Commercial Growers 2017 mwveguide.org and in the extension bulletin Downy Mildew of Pumpkin https://www.extension.purdue.edu/extmedia/BP/BP-140-W.pdf.  Note that downy mildew of cucurbits and downy mildew of soybeans are not caused by the same organism.  Please call Dan Egel if you have questions or concerns.

Figure 3: The pumpkin plants in the foreground of this photos have yellow leaves.

This time of year, I receive many complaints of pumpkin plants with yellow leaves. There can be many reasons why pumpkin plants have yellow leaves. The most common reason for yellow pumpkin leaves doesn’t have anything to do with a disease that can spread from plant to plant. Usually, the reason for the yellow pumpkin leaves has to do with lack of water, weather that has been too hot, nutrient deficiency or other stresses. The photos and discussion below will, I hope, illustrate my point. Let’s say you have a pumpkin field where you have pumpkin leaves that are yellow and you are wondering about the cause. You may want to ask yourself, which leaves are yellow and where are they yellow. In Figure 1, yellow pumpkin leaves may be observed.  When one looks a bit closer to find out where the yellow leaves are, one can see that the[Read More…]

Figure 1. Powdery mildew causes talc-like lesions on pumpkin leaves.

Powdery mildew is a common disease of cantaloupe and pumpkin in Indiana. Occasionally, I observe this disease on watermelon as well. Recently, I have noticed more powdery mildew than usual on watermelon. If left uncontrolled, this disease can cause loss of foliage, loss of yield and lower quality fruit. This article will discuss the biology and management of powdery mildew of cucurbits with an emphasis on watermelon. Powdery mildew is relatively easy to recognize; talc-like lesions occur on both sides of the leaf (Figure 1).  (This article https://vegcropshotline.org/powdery-mildew-symptoms-vs-variegated-leaves/ has additional information about powdery mildew symptoms. ) The fungus that causes powdery mildew, Podosphaera xanthii, does not require leaf wetness for infection of leaves, only high humidity. The optimum temperature for disease development is 68 to 81°F. P. xanthii may survive for a period in crop residue as a resilient fungal structure, but the disease is so easily windborne, that crop rotation is not always[Read More…]

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One of the most common diseases of pumpkin in Indiana is powdery mildew.  Growers are naturally anxious to observe whether the fungicide they have been applying for this disease has been effective.   Therefore, many pumpkin growers scout their fields for disease. Although powdery mildew is relatively easy to recognize, it is possible to become confused.   Figure one shows two pumpkin leaves.  The bottom leaf has the white, sporulation of the powdery mildew fungus in colonies randomly scattered across the leaf.   The top leaf, has silvery coloration primarily along the vein.  This latter leaf is a healthy variegated leaf.   Some pumpkin varieties show this type of variegation more than others. It may be a good idea to study the photo shown here so that one can tell the difference between a pumpkin leaf with the disease powdery mildew and a healthy leaf that is merely variegated

After harvest, storing vegetables in optimal conditions is important to ensure the whole season’s hard work has paid off. This article discusses the optimum storage conditions for tomato, pepper, cucumber, watermelon, cantaloupe and sweet corn. Tomato Ideal storage conditions for tomatoes depend on the maturity stage of picking. If tomatoes are picked at mature green, store them in 66 to 70°F with 90 to 95% RH would encourage uniform ripening. Temperatures above 81°F reduce intensity of red color and reduce fruit shelf-life. Green tomatoes are chilling sensitive. If the temperature is below 55°F, fruit may develop chilling injury. Red tomatoes are safe to store at 50°F, however, flavor and aroma may be negatively affected compared to storing them at 55°F. Pepper Optimum storage condition for peppers is 45 to 55°F with 90 to 95% RH. Temperatures lower than 45°F may cause chilling injury. Colored peppers are in general less chilling[Read More…]

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