Wenjing Guan

Vegetable Crops Hotline Editor & Clinical Engagement Assistant Professor
Department of Horticulture and Landscape Architecture
Area(s) of Interest: Commercial Vegetable and Melon Production
Wenjing Guan's website

206 articles by this author

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Agricultural producers face a plethora of wildlife issues on the farm, from biosecurity in animal agriculture to food safety requirements for fresh produce farmers. Many wildlife species have social or economic value and may be regulated or protected, constraining timely mitigation strategies. Additionally, research and science-based management recommendations to help farmers address wildlife on the farm are limited, available for some crops and pest species but not others. The last national United States Department of Agriculture (USDA) survey of U.S. wildlife damage to agriculture took place in 2001 and estimated $944 million in losses. At the national level, primary wildlife species resulting in losses to field crops included deer, turkeys, raccoons and waterfowl (collectively 75% of the reported losses), with 22% attributed to other species. For vegetables, fruits and nuts, deer, ground squirrels and other small rodents, crows, raccoons and rabbits were most frequently reported (64%), with other species accounting for 36%[Read More…]


Figure 1. Broccoli grow leaves in the head. A response toward heat stress (Pictures was provided by ANR educator Luis A. Santiago)

Cool nights have finally arrived after the first week of October. Before, we had quite a few days when temperatures were above 90°F. The unusual high temperature has caused problems on early-planted broccoli. Broccoli is a heat-sensitive crop. The critical period for heat sensitivity is when plants shift growing tips from vegetative growth to flower bud initiation. This is about 10 days before the crown is visible. Temperatures above 90°F during the critical period cause injury on the flower buds. As the crown continues to grow, an uneven head becomes noticeable, and these heads are inclined to be affected by pathogens. Another response broccoli often has toward the heat stress is to grow leaves in the head (Figure 1), although it may be less a concern compared to bud damage. Varieties are varied by heat sensitivity, and they may have slightly different responses toward high-temperature. For example, the very popular[Read More…]


Although high tunnels make it possible for Indiana farmers to grow vegetables year-round, many growers may choose to end the production season in the fall. After a busy summer, it is not unusual that off-season management is overlooked. Nevertheless, these good management practices determine the success of the next year. It is an old lessen, but we can never put too much emphasis on the importance of good management practices during the off-season. Terminate plants after final harvest, and remove crop residues out of the tunnel. The worst scenario I have ever seen was a high tunnel full of weeds in late fall, and a few tomato plants still standing in the middle of the weeds. No doubt, the plant materials provide a cozy environment for insect pests to survive the winter. Under the ground, the roots of tomato plants, as well as roots of several weeds continue to feed[Read More…]


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Date: October 26, 2019 8:30 am sign-in Location: Elkhart County Fairgrounds 17746 County Rd. 34, Goshen, IN 46528 Home and Family Arts Building This one-day hands-on workshop will offer a view into aquaculture and aquaponics water quality parameters and considerations. The day will consist of information that will benefit new and established producers. More information about the event and registration: indianaaquaculture.com/shop


This is the final issue of the Vegetable Crops Hotline (VCH) for 2019. Subscribers who receive a paper copy in the mail need to renew. A renewal form is included with this issue. We are providing up-to a three years’ subscription of VCH at a reduced price (1 year for $15, 2 years for $25, and 3 years for $30). You can check the date on the right bottom corner of your VCH envelope to find what year your subscription will last through. You can sign-up for Veggie Texts with the same form. Email subscribers will remain on the subscription list for VCH as long as the email address works. Email subscribers will need to send us an email or call us to sign-up for Veggie Texts. An Indiana Vegetable Grower Association (IVGA) membership form is included here too. IVGA membership no longer automatically includes the VCH subscription. You need to indicate[Read More…]


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Date: November 14, 2019 5:00 pm (EST) Location: Southwest Purdue Ag Center (SWPAC) 4369 N. Purdue Road, Vincennes, IN 47591 This event is a great opportunity to learn about watermelon, cantaloupe and other specialty melon production regardless if you have been growing watermelon all your life or are new to this crop.  The meeting will start at 5:00 pm with a casual discussion about this production season. We will solicit topics for the upcoming Southwest Indiana Melon and Vegetable Growers Annual Meeting, which will be held in French Lick, IN on March 13, 2020. At 6:00 pm, dinner will be served. Following the meal, we will present the variety trial results including 40 seedless watermelons, 18 personal-size watermelons and 30 varieties of cantaloupe and specialty melons. Any grower interested in becoming a member is invited to attend the meeting. Membership dues are $15 per year and can be paid at this[Read More…]


Farmer Rancher Program This program is for farmers/ranchers to explore innovative sustainable agriculture solutions to production, marketing, labor, and other problems. This grant is offered as individual ($9,000 maximum), team of two farmers or ranchers ($18,000 maximum), or group ($27,000 maximum). Projects may last up to 24 months. Proposals are due December 5, 2019. Interested applicants can find the call for proposals online as well as useful information for completing a proposal at https://www.northcentralsare.org/Grants/Our-Grant-Programs/Farmer-Rancher-Grant-Program  Partnership Program This program is intended to foster cooperation between agriculture professionals and small groups of farmers and ranchers to catalyze on-farm research, demonstration, and education activities related to sustainable agriculture.  Partnership Grants are funded for up to 24 months. Up to $40,000 total funding request per application is allowed. The deadline for Partnership Program proposals is October 24, 2019. Interested applicants can find the call for proposals online at https://www.northcentralsare.org/Grants/Our-Grant-Programs/Partnership-Grant-Program


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Vegetable Field Day at Pinny Purdue Ag Center  Date: Aug. 13, 5:00 pm CDT. Location: Pinney Purdue Ag Center. 11402 S. County Line Rd., Wanatah, IN 46390. Just north of US 30 between LaPorte and Porter Counties The public and those who raise vegetables commercially or as a hobby are invited to a vegetable and high tunnel field day on Tuesday, August 13, at Pinney Purdue Ag Center (PAC), 11402 South County Line Road, Wanatah. This Purdue Extension program begins at 5:00 pm CDT. Participants will hear some presentations from Purdue specialists then can choose a track on vegetable production or utilizing fresh vegetables. Laura Ingwell, Purdue Extension entomologist, will provide tips on organic insect management and will discuss the melon pollinator research project she is overseeing at Pinney PAC. Liz Maynard, Purdue Extension commercial vegetable specialist, will review and demonstrate the benefits of biodegradable plastic mulch for use with[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…]


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Small Farm Education Field Day at Purdue Student Farm  Date: August 1, 2019 Location: Purdue Student Farm, West Lafayette, IN 47907 The Purdue Student Farm is proud to announce its second annual Small Farm Education Field Day. The event is packed with educational sessions during the morning, followed by a tour and hands-on experiences on the farm. Topics of discussion throughout the day include basic planning tools for a sustainable small farm operation, testing and restoring soils in urban and peri-urban systems, scheduling crops in high tunnels, using different cover crops to build your soil, calculating profits and return on investment using enterprise budgets and food safety plants for small growers and gardeners. During the afternoon there will be a rototiller versus power harrow, high tunnel tomato and sweet pepper production, leaf mold composting, vegetable wash station design, and solar dryer demonstrations. Registration fee is $20. Register here https://purdue.ca1.qualtrics.com/jfe/form/SV_3qQfl05iryF3COp Registration[Read More…]