Horticulture Research

harc apples

Bruce A. Barrett, Ph.D., Associate Professor, Department of Entomology, and State Extension Entomology Specialist. Dr. Barrett conducts basic and applied research leading to the development of integrated pest management (IPM) tactics for fruit tree and nut tree pests, particularly the codling moth, redbanded and obliquebanded leafroller, Oriental fruit moth, and lesser chestnut weevil. Building on previous research findings, tree fruit tree and nut tree entomology studies will include

  • Establishing biological data regarding the orientation mechanisms and preferences of the lesser chestnut weevil toward chestnut plant volatiles. This is accomplished by indentifying the components of volatile organic compounds, evaluate the weevil’s behavior to them, study the role spring and fall emergence plays on seasonal changes occuring in reproductive organ development, and to evaluate the weevil’s phisiological response to chestnut volatiles.
  • Examining the biology and ecology of key apple pests found in the Midwest, such as the codling moth, Oriental fruit moth, and redbanded leafroller to form a foundation of basic biological information to develope a successful pest management program. During the past couple of decades, many areas of agriculture in the United States have been under pressure to control key arthropod pests with a variety of management approaches.Some of the primary reasons justifying this need for a diversity (and more balanced use) of control tactics include the loss of key broad-spectrum chemicals due to legislation and/or resistance development, and to the growing public interest in pesticide use as it relates to human health and enviornmental impact. Such conditions have stimulated the research and development of alternative approaches to pest management that incorporate biologically/culturally based tactics with chemically based tactics (integrated pest management).

Christopher J. Starbuck, Ph.D., Associate Professor, Department of Horticulture, and State Extension Specialist for Woody Ornamental Plants. Dr. Starbuck’s research at HARC is focusing on the horticultural uses of composted and uncomposted organic waste products and the evaluation of ornamental plants. Development of the Missouri Gravel Bed System as a technique to facilitate the handling of bare root nursery stock continues.

  • Composting — A major objective is to focus on overcoming barriers to horticultural use of sawdust and manure compost and to explore developing a market for this valuable resource. Nurseries, greenhouses, landscape contractors and turf managers are potential large-scale users of compost. Sawdust and manure compost is a product that can be produced continuously using uniform ingredients. Research will also focus on evaluating the performance of compost as a soil amendment and practical criteria will be developed to evaluate compost quality. Field studies will be conducted to document the effects of soil amendments with compost on growth of turf and ornamental species.
  • Missouri Gravel Bed — This system shows promise as a means of extending the planting season for bare root plants. Experiments will focus on plant nutrition in the gravel bed and how to maintain optimal levels for several species of plants.
  • Plant evaluations — Plantings will be developed that will allow nurserymen and plant enthusiasts to compare the merits of various species and cultivars based on observation of mature species. Plant evaluations are an important component of the HARC’s research agenda. In collaboration with HARC staff, Dr. Starbuck has worked to secure plants from nurseries and individuals, and from the North Central Regional Plant Introduction Station at Ames, Iowa, for the NC-7 Regional Ornamental Evaluation Trials and the National Crabapple Trials. More recently, plant material has been sent from the U.S. National Arboretum for evaluation. Examples of ornamentals that have been planted at the research center are disease-resistant elms from the National Arboretum(Ulmus americana ‘Valley Forge,’ U. Hybrid ‘Patriot’); birches from Forest Lawn and Forrest Keeling Nurseries (Crimson Frost and Whitespire, respectively); crabapples from the National Crabapple Trials; pears from Stark Brothers Nursery; and viburnums from Forest Lawn Nursery. Among the plants from the Plant Introduction Center in Ames, Iowa, are ashes, oaks, and virburnums.

Michele Warmund, Ph.D., Associate Professor, Department of Horticulture, and State Extension Horticultural Specialist.

Dr. Warmund’s research focuses on horticultural improvement of Black Walnut, Chinese Chestnut, and apple and peach trees. Studies include the following:

  • Economic efficiency of paddock vacuums compared to nut wizards in harvesting chestnuts at different labor costs and production levels
  • Disinfecting chestnut scion wood to kill the Asian Chestnut Gall Wasp by determining the highest temperature that scion wood can be subjected to without tissue injury, evaluate hot water, hot air, and radio frequency as heating methods, and verify that treated wood does not affect graft survival and tree growth
  • Use of transmission electron microscopy to study the galls induced from the feeding and or mechanical action by the Asian gall wasp on the stems and leaves of chestnut trees
  • Use of Florel treatments to effectively reduce the number of secondary catkins on chestnut trees
  • Use of transmission electron microscopy to study the damage and galls produced by the walnut petiole gall mite on black walnut
  • Fruit research focuses on the effect of rootstocks on the growth, fruit productivity, and cold hardiness of peach and apple trees. Rootstock trials conducted at the research center are part of a nationwide effort to provide research-based recommendations to producers. Because Missouri is located in the transition zone of the U.S., the research center is an ideal location to test the susceptability of fruit buds to low winter temperatures and spring frosts.