142 articles tagged "Cucurbits".

Two types of injury on young warm-season vegetable plants are caused by low temperatures: frost/freezing injury and chilling injury. Frost/freezing injury occurs when temperatures drop below 32°F. Ice formation in plant tissues cut cell membranes. When the tissue thaws, the damage results in fluids leaking from the cell, causing water soaked damage. Frost/freezing injury is detrimental to warm-season vegetables, such as melons, cucumbers, tomatoes, peppers, beans. To avoid damage, the best way is to plant warm-season vegetables later in the spring, after the last frost has passed. However, weather is difficult to predict, and there is a growing trend of planting early to achieve early harvests. For the early planted warm-season vegetables, here are a few suggestions that may protect plants from low temperature damages. Covering. The idea of covering the seedlings is to create a microclimate around plants. Because the heat accumulated in soil irradiate back at night, covering[Read More…]


Figure 1. Cucumbers start to wilt following a night average soil temperature was 58 °F

Chilling injury occurs when temperatures are above 32°F and below 55°F. The plant tissue becomes weakened that leads to cellular dysfunction. The most noticeable visual symptom of chilling injury is leaf and hypocotyl wilt (Figure 1). This is caused by the rapid decline in the ability of roots to absorb and transport water. It also caused by the plant’s reduced ability to close stomata. If temperatures do not improve, plants may be killed. Low temperatures also have an effect on mineral nutrient uptake of the plants. Absorption of ions by roots is difficult, as well as their movement in the above-ground parts of the plants. As a result, chilling injured plants often show symptoms similar to nutritional deficiency. Although warm-season vegetables are all susceptible to frost/freezing damage, their susceptibility to chilling injury varies among plant species. Pepper plants seem to have greater difficulty recovering after chilling injury compared to tomato[Read More…]


Bacterial wilt is a serious pest of cucumbers and melons. This disease is caused by the bacterium, Erwinia tracheiphila. However, it is spread by the striped or spotted cucumber beetle. Most management schemes have concentrated on controlling the cucumber beetle in order to lessen the severity of bacterial wilt. Currently, management of bacterial wilt often takes the form of a soil applied systemic insecticide such as Admire Pro® at transplanting and follow up pyrethroid products applied foliarly about 3 weeks post transplanting. The pyrethroid applications are made when the 1 beetle per plant threshold is met. Every year, there is a melon variety trial at the Southwest Purdue Agriculture Center in Vincennes, IN. In 2018, the trial included several specialty melon varieties. We noticed more bacterial wilt than usual (Figure 1). Therefore, we decided to rate the varieties to see if there were any differences in susceptibility. Figure 2 shows[Read More…]


Gowers always want to know which variety is the most suitable one for their farming location and market. I do understand the frustration of growers when looking online at all the varieties being sold by different vendors. There are a plethora of varieties available that have different fruit types and growth habits. Characteristics like potential yield and disease resistance are always important considerations for growers. Which variety will work best for my farming operation and market? During 2018, I attempted to address growers’ concerns and need for local variety performance data, hosting a zucchini field trial at the Throckmorton Purdue Agriculture Center/Meigs Horticulture Facility, Lafayette, Indiana. How was the evaluation conducted? Soil of the test plot comprised of a Toronto-Millbrook (47%) complex, Drummer (27%) and Starks-Fincastle complex (26%) (ranged from a silt loam to silty clay loam). The spring 2018 soil test showed 2.8% organic matter, pH 5.7, and 34[Read More…]


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…]


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