Liz Maynard

Clinical Engagement Assistant Professor of Horticulture
Department of Horticulture and Landscape Architecture
Liz Maynard's website

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Purdue Extension is planning educational sessions for the Illiana Vegetable Growers Symposium (Jan. 7, 2020 in Schererville), Indiana Horticultural Conference (Feb. 11-13, 2020, in Indianapolis), and others. Your suggestions for topics and speakers that will be useful for your operation help us plan the programs. Phone (219) 548-3674, email emaynard@purdue.edu or text (219) 508-1644 your ideas to us soon! Thanks!


The sweet corn variety plots at Pinney Purdue provide a good chance to observe sweet corn insects. In late July I observed two caterpillars that surprised me. The first was European Corn Borer (ECB), in the tassel where they are often found (Figures 1 & 2). It was a surprise because I have seen many fewer of these in the sweet corn plots in recent years. I understand from the entomologists that it is due to the widespread use of Bt field corn that has resulted in much lower populations of ECB. The week of Aug. 19 I observed an ECB egg mass on a flag leaf and a young larva on the ear (Figures 3 & 4). The second late July observation was a corn earworm (CEW)–the insect itself is not surprising, but it was in the tassel! (Figures 5-8). I have previously only seen them in ears. The[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…]


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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…]


Figure 2. Wilt of watermelon seedlings due to grown in a high EC medium.

Producing healthy transplants is a critical step for a successful growing season. Choosing the proper growing media is an important first step. Supported by a USDA Specialty Crops Block Grant through the Indiana State Department of Agriculture, researchers from Purdue have been evaluating different organic growing media with and without adding supplemental organic fertilizers for tomato and cucurbit transplant production. In this article, we have highlighted a few transplant symptoms that are associated with growing media with excessively high or low electrical conductivity (EC) or pH. It is always a good idea to test EC, pH, and other important nutrient content of a medium when you are making your own or using an unfamiliar media. Most soil laboratories provide a saturated media extract test that provides information on these important parameters. More information about this test and suggested range of EC and pH can be found in this article http://www.soiltest.uconn.edu/factsheets/InterpSMEGreenMedia.pdf[Read More…]


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Dual Magnum® has had a special local needs (24C) label in Indiana for use on transplanted bell peppers and other vegetables for a number of years. Last week the label was amended to include additional small fruit and vegetable crops, including asparagus. The new 24C label is available on the National Pesticide Information Retrieval System web site: http://npirspublic.ceris.purdue.edu/state/state_menu.aspx?state=IN. To find it, type “SLN IN” and “130003” in the first two boxes for “EPA Registration Number” and click the search button. The product report will show  “DUAL MAGNUM – TRANSPLANTED BELL PEPPERS.” Click on the ALLSTAR symbol. On the page that opens, click on the Company Label ID number “IN0816048DA0319.” This will open a pdf of the label. If you decide to use the product, carefully read and follow the label instructions.


Bolting of crops overwintered in high tunnels is common in the spring. ‘Bolting’ refers to lengthening and blooming of the flowering stalk. Bolting is often a problem because the quality of the marketable part of the plant declines. Also, plants subject to bolting are programmed to die once they complete flowering and seed production so yield will decline in quantity as well as quality. Sometimes bolting is not a problem because the stalk, buds, and flowers can be sold as a new product while they last; this is often the case with kale,  mustards and related crops. Crops susceptible to bolting include those in the mustard family such as kale, mustards, tatsoi, bok choy (pac choi), mizuna, turnip, radish, etc.; carrots; beets and in some cases Swiss chard; onions; lettuce; and spinach. (Figure 1)   Bolting is triggered by environmental conditions. Some plant types are triggered to develop flowers by[Read More…]



Presentations from many past Purdue educational programs for vegetable growers are available online at https://ag.purdue.edu/hla/fruitveg/Pages/presentations.aspx. Slides from the 2019 Illiana Vegetable Growers Symposium are available now. Indiana Hort Congress presentations will be available soon. 


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Getting seedlings off to a good start begins with a good growing medium for transplants. Growing media for organic production must meet the guidelines set out by the National Organic Standards Board, including not containing any synthetic substances (unless they have been approved for that use) or any prohibited materials. A number of products meet those criteria, and many of them are listed by the Organic Materials Review Institute (OMRI) to document that they meet the criteria. Last year, with funding from a USDA Specialty Crops Block Grant through the Indiana State Department of Agriculture, a group at Purdue began evaluating commercially-available, OMRI-listed growing media for vegetable transplant production (Table 1). Table 1. Growing media used in transplant production trials, 2018. Product Abbreviation Source Johnny’s 512 J512 Johnny’s Selected Seeds Morgan Composting 201 M201 Morgan Composting Penn Valley Potting Soil PENN Penn Valley Farms PromixMP Organik PMPO BFG Supply Seed[Read More…]