In response to the many questions about this disease on cucurbits, a new extension bulletin has been produced. The bulletin may be accessed at the link below. Or contact me to get your copy. https://www.extension.purdue.edu/extmedia/bp/bp-204-w.pdf
Dan Egel
Ever year, I put together fungicide schedules for cucurbits. These may be found at purdue.ag/pumpkinfs and purdue.ag/melonfs. They may be downloaded as PDFs on legal sized pages. Please use these tables along with the MW Vegetable Production Guide and the fungicide label. If you have trouble with accessing the tables or have other questions. please let me know.
From time to time, I will make changes to the MW Vegetable Production Guide. These changes will appear automatically in the on-line version. For those who purchase a hard copy, watch the Vegetable Crops Hotline for changes. See below for the changes that have been made to the Production guide for 2019 Page Comment 1 Add “Anthony Hanson, IPM program” under contributors, University of Minnesota 117 Under powdery mildew, last sentence in disease notes-“Protect pumpkin vines until approximately 21 days from last harvest.” 128 FRAC code for Actigard should be P01 147 Buckeye rot products, Orondis Opti 3-day PHI. 148 Under late blight, Orondis Opti 3-day PHI. 164 Footnote 2 should read “X=permitted for at least one crop.” Footnote 3 should read “X=may be used for that crop. *=processing crops only.” 226 Define herbicide should be omitted.
The Midwest Vegetable Production Guide for Commercial Growers 2018 is available for sale as a hardcopy ($15) or free on-line (be sure to check the article in this issue about changes that have been made to the on-line version). Actually, the Vegetable Guide has been available since last December. The guide may be purchased through the Education Store, at various extension meetings held around the state or from your Purdue University county educator. The website to either view or purchase the Guide, known in Indiana as the ID-56, is mwveguide.org. The Midwest Vegetable Production Guide is a collaboration of 8 states and 9 institutions. Are you thinking that you already have a Vegetable Guide from a past year and wondering if it is worth getting a new one? The article below represents just some of the changes to this year’s Vegetable Guide. New and Revised Sections The three new tables created last year — Selected Information About[Read More…]
A recent observation of gummy stem blight on a watermelon transplant has reminded me to remind growers to inspect seedlings. Whether one is growing transplants or receiving transplants for delivery, seedlings should be inspected for possible disease problems. If one is uncertain of the cause of the symptoms, an official diagnosis can be obtained by sending the sample to the Plant and Pest Diagnostic Clinic. Below I will describe several common transplant diseases of cantaloupe and watermelon as well as management options. I have had similar articles in the Hotline in the past, however, I will use new photos here. Gummy stem blight on transplant seedlings may be recognized by the water-soaked area of the stem near the seed leaves. In this article, I will show a leaf with a lesion of gummy stem blight (Figure 1). A closer look (one may need a 10X hand-lens) at any gummy stem[Read More…]
This disease was recently observed in a tomato greenhouse. This article will review tomato spotted wilt virus symptoms, biology and management. Tomato spotted wilt virus (TSWV) and the closely related Impatiens necrotic spot virus (INSV) are usually observed in greenhouse or high tunnel situations. Both TSWV and INSV affect many hosts, including vegetables and flowering ornamentals. Symptoms vary according to host, stage of plant affected and environmental conditions. Both diseases can cause stunting, yellowing, necrotic rings, leaf mottle and more. Figure 1 shows a tomato leaf with a necrotic mottle caused by TSWV. Figure 2 shows tomato plants stunted as a result of infection by TSWV. Additional symptoms may be viewed here . Since the symptoms of these two viruses vary, plants with suspicious symptoms should be submitted to the Purdue Plant and Pest Diagnostic Laboratory for confirmation of virus symptoms. TSWV and INSV cannot spread without thrips. Thrips are small[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…]
Midwest Vegetable Production Guide for Commercial Growers 2019 update-The on-line version of this guide has been updated. See below and update your hard copy. Page Comment 1 Add “Anthony Hanson, IPM program” under contributors, University of Minnesota 117 Under powdery mildew, last sentence in disease notes-“Protect pumpkin vines until approximately 21 days from last harvest.” 128 FRAC code for Actigard should be P01 147 Buckeye rot products, Orondis Opti 3-day PHI. 148 Under late blight, Orondis Opti 3-day PHI. Footnote 2 should read “X=permitted for at least one crop.” Footnote 3 should read “X=may be used for that crop. *=processing crops only.” In addition, a table of watermelon evaluations have been added to the cucurbit section on page 120.
Chateau SW® herbicide now has a 24(c) special local needs label for cucurbits. This product is produced by Valent, but the label is held by the Indiana Vegetable Growers Association (IVGA). To obtain a label, one must be a member of the IVGA, pay an annual $100 processing fee, read and understand the ‘conditions for use’ and have the appropriate forms signed and notarized. One cannot use Chateau SW® without completing these forms and obtaining a label. This process must be repeated every year. Chateau® can only be used in row middles between raised plastic mulch beds that are 4 inches higher than the treated row middle. The mulched bed must be at least 24 inches wide. The application must be directed between rows with a shielded sprayer. Chateau® cannot be applied post-transplant. Do not apply more than 4 oz. of Chateau® per acre at a broadcast rate during a single application.[Read More…]
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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