118 articles tagged "Cucurbits".

Figure 2. Personal size (mini) watermelon cultivars.

Watermelon variety trials are conducted every year at the Southwest Purdue Agricultural Center in Vincennes, IN. In the 2018 trials, it included 38 standard-size seedless watermelon cultivars and 10 personal-size watermelons. This article discussed the top yielding varieties in our trials in 2018. The full report of the variety trials, and  information about the previous trials  can be found at https://ag.purdue.edu/arge/swpap/Pages/SWPAPPDFPresentstions.aspx Standard size seedless watermelons Tailgate is a new cultivar from Seminis. First time entered into our evaluation in 2018. Tailgate had the top yield variety in the 2018 trial. It produced large-sized fruit, average fruit weight was 18.5 lb, 37% fruit in 36 counts and 20% in 30 counts category. Firm flesh, good quality. Tailgate was one of the five cultivars that did not have hollow heart fruit among the 12 fruit selected for the quality test. Bottle Rocket had a consistent high yield in both 2017 and 2018 trials.[Read More…]


Figure 1. An orange-flesh watermelon with the tiger-striped rind pattern

With the growing interest from consumers looking for new, unique products, yellow– and orange-flesh watermelons might create opportunities for small-sized growers to differentiate their products. This article answers a few questions you may have about growing and marketing these unique type of watermelons. Yellow and orange-flesh watermelons usually have narrow strips with varying degree of green color as the background. The rind pattern is sometimes called tiger-striped rind pattern. There are also some cultivars that have similar outside appearance as the typical red-flesh watermelons. Like red-flesh watermelons, both seeded and seedless types of yellow- and orange-flesh watermelons are commercially available. Some examples of cultivars are listed in the table below. Table 1. Example yellow- and orange- flesh seedless and seeded watermelon cultivars and their seed sources. Cultivar Flesh color Size (lb.) Shape Seed Source Seedless cultivar Amarillo Yellow 13-15 Round Jo, Si, Ru Lemon ice Yellow 10-12 Oval-round NE, Ho Orange[Read More…]


Tomato and Cucumber growers who are interested in grafting tomato and cucumber plants by themselves may find this information helpful. Step-By-Step instruction of how to graft tomato plants is available from Purdue Extension publication Vegetable Grafting: Techniques for Tomato Grafting https://mdc.itap.purdue.edu/item.asp?Item_Number=HO-260-W as well as a Purdue Extension video https://www.youtube.com/watch?v=7Ufx66Isf88 A cucumber grafting instruction was also recently released. It provides step-by-step guidance of cucumber splice grafting technique. The publication is available at https://www.extension.purdue.edu/extmedia/HO/HO-328-W.PDF


Figure 1. Striped Cucumber Beetle feeding on a watermelon.

Striped cucumber beetle can be a significant pest in watermelon production systems. These pests can cause feeding damage to roots, stems, leaves, and flowers of plants as well as the watermelon fruit itself (Figure 1). In large enough densities, this damage can lead to economic loss. The economic threshold for striped cucumber beetles in watermelon has been set at 5 beetles per plant, since they are not susceptible to bacterial wilt. When densities of the beetles reach this level, growers should treat their fields with an insecticide to avoid yield loss. To make good decisions, pest densities should be determined with scouting. To investigate the pressure of striped cucumber beetles on commercial watermelon fields in Indiana we worked with 16 growers during the summers of 2017-18. Fields ranged in size from less than half an acre to 100 acres. The growers used a variety of management strategies and insect scouting[Read More…]


Insecticides are often needed to control pests in vegetable crops, but in crops that require pollinators we often worry about the impact those insecticides may have on those pollinators (Figure 1). In the summer of 2018, a team of researchers at Purdue University explored the effects of insecticide applications on watermelon yield across Indiana, considering their impacts on both pests and pollinators. Using 5 of the Purdue Agricultural Centers (PACs), pairs of ½ acre watermelons plots were planted, each in the middle of a 15-acre corn field (10 total plots) (Figure 2). The two watermelon plots at each site were assigned either to a conventional or an integrated pest management (IPM) system. The corn surrounding the conventionally managed watermelons had a neonicotinoid seed treatment, the watermelons were given a neonicotinoid soil drench at transplant, and 4-5 pyrethroid sprays were applied throughout the summer regardless of pest pressure. The IPM system[Read More…]


Figure 1. Cucumbers were grown in a greenhouse in April 2018

Cucumbers are extremely sensitive to cold. Locally grown cucumbers are almost only available in the summer. While in Asia, without the use of fancy heated greenhouses, cucumbers can grow all winter. Growing grafted cucumbers with cold tolerant squash rootstock is one of the key factors making this possible. Since 2016, we started to evaluate opportunities of using grafted plants to extend early season cucumber production under protected cultural systems in the Midwest. We observed promising results in our research trials. However, knowing research trials can only tell part of the story, we initiated multiple on-farm trials across Indiana to better understand if and under what circumstances growers would benefit from this technique. This article discusses the lessons we have learned so far and raises questions that need to be answered. Heated greenhouses A pronounced advantage of using grafted cucumbers was observed in the situations that cucumbers were grown in soils[Read More…]


charcoal rot

This disease was identified on a long Asian cucumber growing in a high tunnel in Mid-June in Knox County. The first symptom noted was wilting of the cucumber plant. Upon closer examination, a light, gray necrosis was observed on the lower portion of the plant. In Figure 1, you may notice dark spots in the necrotic area. These symptoms, plus the resin-like drops on the stem might look like gummy stem blight. However, a look under the microscope revealed fungal structures and spores that were not from the gummy stem blight fungus. Plus, gummy stem blight is rare in a greenhouse situation where there is little moisture. When we isolated for a fungus, we found numerous micro-sclerotia. The sample was sent up to campus to confirm that the fungus was Macrophomina phaseolina, causal agent of charcoal rot. The charcoal rot fungus has many hosts and the fungus is not new[Read More…]


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With the start of pumpkin harvest, it is a good time to review important considerations for harvest and postharvest storage of pumpkins and winter squash (butternut, acorn and hubbard squash etc.). Pumpkin and winter squash should be harvested fully mature to reach their optimal quality and fulfill their potential for long shelf lives. Characters indicating fruit maturity include loss of rind surface gloss, ground spot yellowing, and hardening of the skin to the level that it is resistant to puncture with a thumbnail. Except for some striped varieties, mature fruit should have solid external color. If fruit have to be harvested pre-mature because of plant decline, these fruit won’t store as well as mature fruit. The best practice is to harvest the fruit as soon as they are fully mature and then store under proper conditions. If mature fruit are left attached to the vines, it increases the chance of[Read More…]


Several pumpkin growers have asked me when to stop managing for pumpkin diseases. That is, when should a pumpkin grower stop applying fungicides? I cannot provide a definitive answer for this question; every grower will have to make his or her own decision. Below, however, are some factors to consider. Estimate the crop yield-walk through the field and evaluate the yield of pumpkins that are ready to harvest. Be sure to only consider fruit of marketable quality. If the yield is at or above what is expected, it may be time to put the sprayer away. Estimate when harvest will take place-Pumpkins that are scheduled for harvest in the next week or two are less likely to need any fungicide treatment. A longer period to final harvest may indicate that there is time for immature fruit to ripen. For example, pumpkins that are to be picked by the consumer up to Halloween may have time to mature.[Read More…]


Many of us may forget about the pesky squash vine borer until it’s too late. This pest of cucurbit crops tends to be sporadic in our region; you are either battling it every year or it hardly makes an appearance. The squash vine borer is a member of the clear-winged moths, a unique group of moths that are active during the daytime. They are very beautiful with their bright colored orange tufts on their legs (Figure 1), but can be devastating. The insect overwinters as a late instar larvae or pupa in the soil. When the weather warms, they mature and adults emerge. You can scout for the first generation of adults in the spring and should target pesticide applications at the base of the plant when adults are first spotted and for two weeks thereafter. If you wait, the eggs will hatch and the larvae will bore into the[Read More…]


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