142 articles tagged "Cucurbits".

Dear Watermelon Growers, At our past winter technical meeting, several growers suggested fertilizer recommendations need to be reevaluated for watermelon production in our area. This suggestion is timely and critical. We plan to initiate a project for the 2020 watermelon production season to reevaluate the fertility and irrigation practices used in Indiana.  We will identify 7-10 watermelon fields with different irrigation and fertility practices. We will collect soil samples and plant tissue samples at different crop growth stages. Lab results will be shared with growers immediately after they are received. Growers who wish to closely watch the nutritional status of the watermelon plants may want to take this free opportunity. As part of this project, we will collect information about fertilizer and irrigation application, and approximate yield of the evaluating field from growers. Summarized results of this project will be shared at the next Southwest Indiana Vegetable and Melon Growers[Read More…]


Warm-season vegetables like tomato, cucumber, pepper etc. often receive premium prices if they were sold at farmers’ markets earlier in the season. The same happens on summer squash, with the different fruit shape and color, summer squash provides a great diversity to the market. High tunnels that  are planted with warm-season vegetables are often closed to maintain heat inside the structure in the spring. Growers often hesitate to bring beehives to high tunnels because of the increased production cost and potential worker safety concerns. Under such circumstances, crops that can set fruit without pollination (parthenocarpic) have an advantage for early-season high tunnel production. Previous studies indicated parthenocarpic character exists in some summer squash cultivars. But such information is not always clearly indicated in seed catalogs. Without knowing the information, farmers may miss the opportunity of growing summer squash and targeting for an early harvest in high tunnels. In the spring[Read More…]


Thanks to the support from NC-SARE, we are going to continue the study of evaluating grafted cucumbers for early season production in greenhouses and high tunnels by collaborating with farmers in 2020. You can find our 2019 on-farm trials’ summary here:  https://ag.purdue.edu/arge/swpap/Documents/Summary%20of%202019%20On-farm%20Grafted%20Cucumber%20Trials.pdf. The same as in previous years, we are going to supply grafted and normal cucumber transplants for free. These plants were grown in a conventional greenhouse using untreated rootstock seeds. What we want from growers is to grow the same number and variety of grafted and normal cucumber plants, and keep track of the performance of the plants and the yields. We will provide a stipend for your efforts in tracking the data. In addition, we encourage farmers to learn grafting technique and produce grafted plants on your own. We will provide you with technical support and help with the process on-site if it is needed. For more[Read More…]


You may be seeing a few “stink bug-like” insects crawling around on your cucurbit crops this time of year. However, these slightly more slender insects are not stink bugs, they are actually squash bugs. Similarly to stink bugs though, they do give off quite an odor when crushed! Squash bug adults and nymphs (immatures) (Figures 1 – 3) attack all cucurbit vine crops, especially squash, pumpkin, cucumber, and melon. These insects feed by sticking their needle-like mouthparts into plant parts to sip on sap. Feeding damage by adults and nymphs can cause significant damage to the fruit and foliage: damaged fruits are disfigured and discolored, and leaves may wilt and become brittle and discolored as well. Generally, squash bugs are not a problem if controlled earlier in the season with insecticides. If not however, it’s still possible to see adults, nymphs, and even egg masses on plants as we move[Read More…]


Winter squash – butternut, acorn, and kabocha – in our downy mildew sentinel plot at Pinney Purdue were showing some wilted and stunted plants by late July (Figure 1). They are easily pulled up, the stem breaking off at ground level, revealing a brown stringy decayed-looking stem base (Figure 2). Sometimes there is a little whitish or maybe pinkish mold on the stem. I cut open a kabocha squash to look for squash vine borer larva and found sap beetles that seemed to be feeding inside the stem, but no vine borer (Figure 3). The sap beetles were clearly taking advantage of an opportunity, but not the cause of the wilt. Perhaps a borer had already come and gone. I used scotch tape to pick up some of the mold and put it on a slide to look at under the microscope. At 100X and 400X I saw among the[Read More…]


Bacterial spot can cause mostly light colored angular lesions on pumpkin leaves.

I have observed this disease in scattered commercial pumpkin and squash fields across Indiana. Symptoms: Bacterial spot causes ⅛-¼ inch angular leaf lesions that are white to light brown in color (Figure 1). These leaf lesions may be accompanied by yellowing (chlorosis). The more important symptom are the lesions on fruit that are scabby to raised, round and a light brown in color. These lesions are often less than ⅛ inch in diameter and do not extend into the surface of the fruit. However, lesions may become secondarily infected in which case lesions can become an inch or more in diameter. Such lesions may grow into the flesh of the fruit (Figure 2). Any type of fruit lesion can ruin the marketability of the fruit. Biology: Leaf lesions, while unimportant economically, are important in diagnosing bacterial spot before fruit is present. This head start allows growers to begin preventive measures.[Read More…]


Downy mildew of cucumber can be recognized by the yellow angular lesions on the top of the leaf.

Cucurbit downy mildew has been observed on cucumber in the southwest corner of Michigan, just across the border from La Porte County and LaGrange Counties, Indiana. All cucurbit growers in Indiana should be scouting for downy mildew. Cucurbit growers in northern Indiana should be managing for downy mildew. The organism that causes downy mildew of cucurbits doesn’t overwinter in Indiana. It has to be blown in every year. It is common for downy mildew to start the season in the Gulf States and migrate north with the cucurbit crops. Downy mildew apparently overwinters in northern Michigan/southern Ontario in greenhouses where cucumbers are grown year round. Therefore, downy mildew is often found in Michigan before it is found in Indiana. In most years, the downy mildew fungus will blow from southern Michigan to Ohio before it tracks south. Many cucumber varieties have some resistance to downy mildew. For susceptible cucumber varieties or[Read More…]


Figure 1. Powdery mildew on cucumbers grown in a high tunnel.

Powdery mildew is particularly severe in high tunnel and greenhouse growing conditions (Figure 1). It affects a wide range of crops including tomatoes and cucumbers. In addition to using synthetic fungicides to control this disease in high tunnels, we found powdery mildew on cucumbers can also be effectively controlled through variety selection and intensive plant pruning. Cucumber cultivars grown in high tunnels are parthenocarpic. Most of these cultivars are marketed as powdery mildew resistance. However, there are actually a wide range of different levels of resistance existed among parthenocarpic cultivars. In our trials, we found Japanese type cucumbers, especially cultivar Tasty Jade, was very susceptible to powdery mildew; Taurus was less susceptible than Tasty Jade, but much more susceptible compared to most Beit alpha (or mini) type, long English (or Dutch greenhouse) type and American slicer cucumbers. Comparing three long English cultivars in our evaluation, Kalunga was more susceptible compared[Read More…]


The 2019 production season started with above-normal rains. The wet conditions affected agriculture production, including watermelon and cantaloupe. In this article, we will review some of the watermelon and cantaloupe problems that are often associated with wet conditions. Manganese toxicity– This nutrient disorder occurs more often on cantaloupe that is grown in soils with pH lower than 5.5. Although liming before planting is a common practice, it is not unusual that we see soil pH that has dropped below 5.5 in sandy soil, especially during wet years. Manganese exists in soil solution as either reduced (Mn2+) or oxidized (Mn3+) form. Plants take up manganese in the reduced form (Mn2+). The proportion of exchangeable Mn2+ increases dramatically as soil pH decreases, and this reaction is promoted in waterlogged soils with low oxygen condition. As raindrops fall through the air, they dissolve CO2 and form enough carbonic acid to lower the pH of[Read More…]


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The wet spring has likely delayed some planting of pumpkins. What does delayed planting mean for yield? Data and observations from Purdue Ag Centers offer some perspective to supplement other experience. Figure 1 shows how pumpkin yield was affected by planting date for 6 trials. Each line represents a different trial. The Y-axis shows relative yield within in each trial. Yield of the first planting date for each trial is set to 100. For the two trials at Pinney Purdue (orange lines, PP2002 and PP2003), pumpkins seeded June 20-25 yielded 70%-85% of pumpkins seeded by early June. In the 1995-1996 trials at Southwest Purdue Ag Center (light green lines, SW1995 and SW1996), pumpkins transplanted June 25-30 produced about 50% of those transplanted two weeks earlier (June 10-15). Transplanting two weeks later (July 10-15) produced only 30% of the yield compared to the June 10-15 plantings. In the 1997-1998 trials at[Read More…]


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