Browsing by Author "Grabowski, Michelle"
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Item Episode 14 Disease Overview for 2018 with Michelle Grabowski: What's Killing My Kale?(2018-09-25) Klodd, Annie; Hoidal, Natalie; Grabowski, MichelleFor our September series of "What's Killing My Kale?", we caught up with some of our Extension IPM experts to discuss the main 2018 growing season pest pressures and how to prepare for 2019. We discussed weeds with Annie Klodd, diseases with Michelle Grabowski, and insects with Bill Hutchison.Item Episode 7 Plant Disease Update Part 2: Disease Identification and Management in Brassica Plants: What's Killing My Kale?(2018-07-11) Klodd, Annie; Hoidal, Natalie; Grabowski, MichelleThis month's episodes of "What's Killing My Kale?" is all about plant diseases. In part 2, we talk with Michelle Grabowski about diseases in Brassica plants, and what growers should be thinking about in terms of scouting and management in the upcoming weeks.Item Exploring the host range of Sclerotinia sclerotiorum in herbaceous ornamental plants(2017-12) Grabowski, MichelleSclerotinia sclerotiorum is a necrotrophic fungal plant pathogen known to infect over 400 species of plants from 75 families. Many popular herbaceous flowering plants are susceptible. Infested flower beds often suffer significant plant loss each year, reducing their ornamental value significantly. Identification of disease resistant plants would be a useful management tool. The objective of this study was to evaluate species of herbaceous ornamental plants with no reported history of white mold susceptibility for potential resistance to S. sclerotiorum. Plant species included Portulaca grandiflora, Pentas lanceolate, Scaevola aemula, Impatiens hawkeri, I. walleriana, Caladium xhortulanum, Canna xgeneralis, and Colocasia esculenta, and the ornamental grasses Pennisetum glaucum, Setaria italica, Juncus inflexus, Carex flagellifera, Isolepsis cernua, and Acorus gramineus. Zinnia elegans x angustifolia ‘Profusion White’ served as a susceptible control. Disease response was evaluated under field conditions and in controlled environments. Direct inoculation of below ground storage organs of some species was conducted to determine the pathogen’s ability to survive and grow in these plant parts. The effect of temperature and wounding was evaluated in ornamental grasses through inoculation of plants grown at 13, 16, 19, or 22C with and without wounding. Detached leaves of representative ornamental grasses were inoculated and stained to determine the pathogen’s ability to penetrate leaf tissue. In field trials, disease incidence was quantified as the number of plants per bed visibly infected with S. sclerotiorum based on signs and symptoms and disease severity was recorded as percent canopy missing due to death of plants within the bed. In controlled environment studies, lesion length was used as a measure of disease severity. Portulaca grandiflora, P. lanceolata, and S. aemula were highly susceptible in a controlled environment but displayed reduced disease severity in field conditions compared to susceptible controls. Impatiens hawkeri and I. walleriana displayed abscission of diseased plant tissue as an unusual resistance response. Caladium xhortulanum was susceptible to S. sclerotiorum. Petioles, leaves, and corms developed a watery soft rot. Colocasia esculenta was resistant to infection. Sclerotinia sclerotiorum infected only wounded or senescent tissue of this species and did not result in significant symptoms under any conditions. Canna xgeneralis was partially resistant to the pathogen. Although canna petals were readily infected, infection of petioles was restricted to small necrotic lesions. Neither infection progressed to the main stem or resulted in plant death. Acorus gramineus was susceptible in field and growth chamber environments, regardless of wounding and temperature. Juncus inflexus, C. flagellifera, and I. cernua were resistant with minor to no symptom development in field and controlled environment studies. The reaction of P. glaucum and S. italica to inoculation varied under different conditions. Disease severity increased as temperature decreased and with wounding. Microscopy studies of ornamental grasses supported results from the field and growth chamber trials. Mycelial penetration of leaf tissue occurred 24 hours after inoculation (hai) for the susceptible entry A. gramineus, 48 hai for the species with intermediate resistance P. glaucum, and was not observed at 24, 48, or 96 hai for the resistant plant entry J. inflexus. This study indicates that I. hawkeri, C. xgeneralis, C. esculenta, J. inflexus, C. flagellifera, and I. cernua have resistance to S. sclerotiorum and could be utilized in an integrated disease management program for infested landscape beds.Item Online Diagnostics & Recommendations for Tree Health(2010-07) Grabowski, Michelle; Hahn, Jeffrey D.; Johnson, GaryDeveloping a suite of online diagnostic tools to help identify insect, disease and abiotic tree problems for the 20 most commonly grown trees in Minnesota. This site will be useful to homeowners, gardeners, woodlot owners and tree care professionals.Item Pest management for the home apple orchard(2011) Hahn, Jeffrey D.; Grabowski, Michelle; MacKenzie, JillMinnesotans who grow apples at home have to combat many insect pests and diseases to produce a good crop. Many apple growers reduce their use of pesticides, while still harvesting quality fruit, through a set of practices known as Integrated Pest Management (IPM). IPM includes a combination of pest management techniques including monitoring for pest problems, removing diseased or infested plant material from the area, and many other cultural control techniques. Pesticide sprays are used in IPM only when necessary, and gardeners may choose from conventional or organic spray options.Item Pest management for the home strawberry patch(2015) Foord, Karl; Hahn, Jeffrey D.; Grabowski, MichelleMinnesotans who grow strawberries at home may have to combat insect pests or diseases to produce a good crop. Previous pest control strategies seeking to eliminate all pests from a garden have been shown to be unsuccessful. Today's approach combines many management methods into an integrated whole, thus the name Integrated Pest Management (IPM). IPM practices have enabled growers to place an emphasis on non-chemical methods while using pesticides secondarily or as a supplement to these methods while still harvesting quality fruit. The philosophy of IPM is to seek a balance maximizing yield while reducing human and environmental risk. This follows a particular hierarchy that begins with the best practices in cultural management.Item Water Wisely: Healthy Plants, Healthy People, Healthy Planet(University of Minnesota Extension, 2016-10) Weisenhorn, Julie; Zuzek, Kathy; Bauer, Sam; Grabowski, Michelle; Froemming, Jackie; Berlin, Beth; Haugen-Brown, Tana; Nelson, Randy; Trott, Robin; Meyer, Mary; Yetka, Leslie; Hahn, Jeff; Foord, Karl; Kenny, Tim; Rice, AndreaWise watering practices in the home landscape save money, help protect Minnesota’s water supply and optimize plant health. Nearly one-third of residential water is used to irrigate home landscapes. Improper watering practices impact the availability and/or quality of groundwater, lakes and streams. Some landscape plants, such as lawns, generally need less water than we think, while trees sometimes need more.