Antonio DiTommaso

 

PROGRAM GOAL AND RESEARCH FOCUS

      The overarching goal of my research program is to study and gain a better understanding of the impact of biotic and edaphic factors on growth, population and community dynamics of agrestal, ruderal, and environmental weeds. An important objective of the program is the development, testing, and implementation of safe, effective, sustainable and economically viable management strategies for troublesome plants we refer to as 'weeds'. To achieve this objective, my research program comprises several major thrusts.

·  Seed biology/ecology

·  Invasive weed biology

·  Biological control, and

·  Integrated weed management.






SEED BIOLOGY/ECOLOGY RESEARCH

      The seed biology/ecology research focuses on understanding the impact of biotic factors such as selective disease and plant competition and abiotic factors such as light, soil fertility, moisture, soil depth on seed dormancy and emergence patterns in weeds of cropping and non-cropping systems.

Current projects focus on the:

·  Effect of maize (Zea mays) planting date and interspecific competition on seed dormancy and seedling vigor of velvetleaf (Abutilon theophrasti)

·  Influence of salinity on the germination behavior of common ragweed (Ambrosia artemisiifolia) seeds collected from plants growing in contrasting habitats

·  Effects of harvest date and storage on seed germinability and seedling vigor of the exotic invasive species, pale swallow-wort (Cynanchum rossicum) growing in different habitats

·  Impact of mulch on soil moisture and emergence of important annual agrestal weeds including pigweeds (Amaranthus spp.), velvetleaf, common lambsquarters (Chenopodium album) and giant foxtail (Setaria faberi).

·  Comparison of weed emergence patterns and vegetative regeneration potential of weeds found on the highly fertile Terra Preta do Indio (anthropogenic black) soils and nutrient-poor oxysols in the Brazilian Amazon.

 

INVASIVE WEED BIOLOGY RESEARCH

      This work focuses on determining those attributes of exotic invasive plants that contribute to their invasiveness and the specific features of habitats that influence their susceptibility to invasion by exotic species.

Current projects focus on the:

·  Seedbank dynamics, reproductive fitness, and dispersal ability of pale swallow-wort (Cynanchum rossicum - syn. Vincetoxicum rossicum) [Asclepiadaceae] in contrasting habitats of central NY State.

·  Role of arbuscular mycorrhizal fungi (AMF) in the invasion process of pale swallow-wort.

·  Impact of pale swallow-wort and black swallow-wort (Cynanchum nigrum) on the population dynamics of the Monarch butterfly (Danaus plexippus), and

·  Growth and expansion of mugwort (Artemisia vulgaris) in contrasting habitats and under different management regimes.

See slide presentation: Swallow-worts: Increasingly Problematic Exotic Vines in NY State

 

BIOLOGICAL WEED CONTROL RESEARCH

Current/Future projects focus on the:

·  Influence of Bt corn for corn rootworm (CRW) (Diabrotica spp. (Coleoptera: Chrysomelidae) control on post-dispersal weed seed predation levels

·  Potential of the rust fungus, Puccinia glechomatis, as a biocontrol agent for ground ivy (Glechoma hederacea) in turfgrass

·  Potential for the classical biological control of pale swallow-wort (Cynanchum rossicum) in North America

·  Impact of the selective fungal pathogen, Colletotrichum coccodes and a seed-eating bruchid weevil on velvetleaf growth and seed production


 

INTEGRATED WEED MANAGEMENT RESEARCH

      The integrated management of weeds (IWM) is a final focus of my research and aims to make use of a combination of control strategies (e.g. cultural, mechanical, biological, chemical) to effectively manage problem weeds.

Current projects focus on the:


·  Effects of chisel and zone tillage and different weed management tactics (chemical and mechanical cultivation) on spatial and temporal weed patch dynamics in a corn cropping system

·  Impacts of tillage intensity and soil fertility management on nutrient dynamics, weeds and crop quality during transition to organic vegetable production

·  Inventory, population dynamics, and management of weeds on Terra Preta do Indio soils.

 

RESEARCH FOCUS

     Chuck Mohler is a senior research associate in the Dept. of Crop and Soil Sciences at Cornell University . His early   career focused on the quantitative study of forest competition and on the population dynamics of succession. Since 1986 his research has been primarily on the ecology of agricultural weeds and ecological methods of weed management. Most of this work has focused on the effects of tillage, cultivation, and crop residue on the population dynamics of annual weeds.

 

Current research projects include:

 

×           Development and field testing of a machine for retaining crop and cover crop residue on the soil surface during tillage

×           Development of a rotation planning manual to facilitate crop rotation planning on organic farms; elucidating the population dynamics of major weeds species on 11 exemplary organic farms throughout the northeastern USA

×           Modeling the movement, survival and emergence of weed seeds during tillage and natural processes

×           Experimental examination of the effects of tillage and inter-row cultivation on the spatial distribution of weeds

×           Examination of the long-term effects of different nutrient sources and rates on weed populations in corn.

 

Mohler serves as the coordinator for a large multi-disciplinary project comparing various organic cropping systems, in which the cropping systems of successful and innovative farmers are duplicated on experiment station farms where they can be studied intensively.

 

 

 

 

Jianying Shen

 

RESEARCH AND TEACHING FOCUS

     The overarching goal of my research program is to establish a rational integrated weed management strategy in China. I am particularly interested in the way in which biotic factors (competition for available resources) and abiotic factors (tillage, nutrients, moisture, temperature, and light) affect weed population and community dynamics in arable cropping systems. My research focuses on the effects of light and temperature on seed dormancy and seedling vigor in important annual and perennial weed species in vegetable cropping systems especially those that make use of herbicide-impregnated mulches such as special fabrics. Another facet of my research is to better understand the biology and population dynamics of the non-native invasive species in China such as alligatorweed (Alternanthera philoxcroides (Mart.) Griesb) so that more effective and sustainable management strategies can be developed. The impact of herbicides on biodiversity of target and non-target organisms, such as soil algae, and especially nitrogen-fixing cyanobacteria is another key component of my research. the integrated weed management progeam is centered on building a rational herbicide application strategy in China, including the parameter order of crop-weed ecological systems based on control parameters l of the system. My research group is also exploring other alternative weed management approaches, such as the harvesting of benficial weeds, improving biotechnology strategies for weed control, using herbicides that are safe to notrogen-fixing cyanobacteria, and the culturing of these beneficial microorganisms. These approaches are also employed to avoid excessive herbicide use, increase bio-diversity of cropping systems, sustain crop production, improve profit margins, and prevent weed community succession and environmental deterioration.

Courses taught by Jianying are as follows:

  • Wild Plant Resources and Development (graduate-lectures), 2004 to present.
  • Bioremediation of Environmental Pollution (graduate-lectures and lab), 2005 to present.
  • Bio-degradation and Pollution Control of Pesticides (graduate-lectures), 2005 to present.
  • An introduction to Water Reseources (graduate-lectures), 2002-present.
  • Weed Science, undergraduate (undergraduate-lectures and lab), 1988 to present.
  • plant Quaratine (undergraduate-lectures and lab), 1989 to present.

 

 

Andrew McDonald

 

RESEARCH FOCUS

     At present, I am a post-doctoral fellow as part of the USDA's National Research Initiative (NRI) (see project summary below). In this capacity and through on-going collaborations with Dr. Susan Riha and Andres Berger in the Department of Earth and Atmospheric Sciences, we are investigating the role of early season environmental factors like temperature, moisture stress, and soil nitrogen status for initiating resource capture hierarchies between maize and weeds. The legacy of these early conditions appears to persist throughout the cropping season and may largely determine both crop yield loss and weed fecundity. By characterizing these relationships and quantifying the comparative plant responses that create them, we aim to develop robust decision support tools that provide farmers a practical basis for reducing post-emergence herbicide use. Additional areas of interest include: root system development and water use in mixed vegetation systems, rice responses to contrasting cultural practices and edaphic conditions, and the application of remote sensing and GIS technologies for assessing landscape-scale ecosystem processes. To complement field and controlled environment experimentation, we also employ dynamic simulation models to integrate and extend our research findings.

 

NRI PROJECT SUMMARY

     Initiatives to develop reliable decision tools for weed management have fallen short of expectations, principally because of significant weather-induced variations in crop damage from competition. Previous findings from New York State suggest that the comparative early height development of maize (Zea mays) and several important weed species is a strong predictor of eventual yield loss. We hypothesize that contrasting responses to early season temperatures are primarily responsible for structuring competitive hierarchies in maize and, ultimately, determine crop yield losses. Our research has three themes: (I) establish the connection between early temperatures and the formation of height hierarchies, (II) quantify the relationship between these hierarchies and eventual maize yield loss as well as weed fecundity, and (III) conceptualize decision tools based on weather data and/or relative height metrics that enable judicious herbicide use. To achieve these objectives, the comparative ecophysiology and interference relationships of maize in competition with four annual weed species (Setaria faberi Herrm., Abutilon theophrasti Medicus, Chenopodium album L., Amaranthus powellii S. Wats.) will be characterized in controlled environment and field conditions under a range of early temperatures. A dynamic competition model with improved early growth algorithms will be applied to extend the experimental findings. Assessment of the early competitive balance in maize systems may provide a practical and reliable guide for weed control that co-optimizes long and short-term management objectives.

 

Kristine Averill

 

RESEARCH FOCUS

     The overall goal of my research is to expand our knowledge of the population biology of the Swallow-worts (Vincetoxicum spp.), two invasive, herbaceous, perennial vines that originated in Europe and now threaten natural areas, pastures, and old field communities in the northeastern U.S. and southern Ontario and Quebec, Canada.

      I am monitoring clonal (vegetative) expansion and reproduction in pale swallow-wort (Vincetoxicum rossicum (Kleopow) Barbar.) at four sites across central New York State and of black swallow-wort (V. nigrum (L.) Moench) at three sites in the Hudson Valley of NY State.  I am assessing growth and population differences among the species and sites, as well as differences between open field and closed forest canopy habitats at the four pale swallow-wort sites.

     In addition, we are conducting a field experiment to determine key parameters that are important for swallow-wort seedling establishment and survival.  From previous research performed under controlled greenhouse conditions, we know that swallow-wort can transition from seed to fruit in approximately four months.  Under field conditions however, we find swallow-wort plants that although giving the appearance of being seedlings, are likely 3-year old or more plants.  At present, it is still unclear how long swallow-wort plants require to attain reproductive maturity under typical NY State field conditions. Therefore, we are examining pale swallow-wort emergence, survival, and growth under different disturbance regimes at two sites near Ithaca, NY to better understand seedling fate in this species.

 The four disturbance treatments are:

(1) above-ground vegetation removal,
(2) above-and below-ground disturbance,
(3) mowing, and
(4) undisturbed old field habitat.

     The various disturbance treatments allow for variation in available resources.  We expect that seedling emergence, survival, and growth will be higher in the disturbed treatments than in the undisturbed old field habitat.  Disturbance-related treatments are likely to result in the availability of more resources, which we hypothesize will increase the ability of swallow-wort plants to survive and reproduce. This field experiment will be carried out for at least two years and possibly longer.
The data obtained will ultimately be used to aid in the development of a biological control program for these two invasive swallow-wort species in North America.  Our collaborators at the USDA-ARS Plant Protection Research Unit (PPRU) in Ithaca, NY, headed by Dr. Lindsey Milbrath, Research Entomologist, are focusing on developing a classical biological control using insects, while colleagues at the USDA-ARS Foreign Disease-Weed Science Research Unit in Ft. Detrick, MD are searching for effective fungal pathogens.

http://www.ars.usda.gov/pandp/people/people.htm?personid=34375

USDA-ARS Foreign Disease-Weed Science Research Unit website:
http://www.ars.usda.gov/main/site_main.htm?modecode=19-20-00-00

 

Lillian Magidow

 

RESEARCH FOCUS

      My undergraduate research at the University of Minnesota used farmer interviews as a way of understanding agricultural issues. My thesis research was conducted in Chiapas, Mexico on the impact of NAFTA on indigenous maize farmers. My honors project publicized the stories of sustainable farming families in Minnesota and Wisconsin. My overall interests range from international agriculture to plant ecology and physiology to building socially just food systems.
      My current research at Cornell seeks to increase knowledge about the biology/ecology of two introduced species of swallow-wort [pale swallow-wort - Vincetoxicum rossicum and black swallow-wort - Vincetoxicum nigrum), both invasive weeds that are problematic in the northeastern United States and adjoining parts of Canada. Ultimately, we hope to contribute to the development of an effective biological control program against the swallow-worts in North America, whether through the use of insects or pathogens. Thus, the main focus of my research is to determine the effects of abiotic soil factors such as soil pH and drainage depth, on the growth and reproductive success of these species. This research will aid in determining what the potential distribution range of the two swallow-wort species is likely to be in the northeastern U.S. and the adjacent Canadian provinces of Ontario and Quebec. My research is part of a larger collaborative effort on the swallow-worts between the Cornell Weed Ecology Research Group and the research team of Dr. Lindsey Milbrath, Research Entomologist, at the USDA-ARS Plant Protection Research Unit in Ithaca, NY.

http://www.ars.usda.gov/pandp/people/people.htm?personid=34375

 

Rachel Shuler

 

RESEARCH FOCUS

      My research is part of an multidisciplinary study at Cornell that investigates how non-target insects, weeds, and soil microbial communities are affected by transgenic Bt corn to control corn rootworm Diabrotica spp., (Coleoptera: Crysomelidae). The likelihood of corn rootworm (CRW) Bt corn replacing a significant percentage of the corn acreage nationwide makes it imperative that we understand both the positive and negative effects of high levels of this protein on agro-ecosystems by comparison to the standard application of soil insecticides.
      Post-dispersal seed predation can be a major source of seed loss, reducing seed supply and seedling emergence in a number of habitats including agricultural systems. Key beneficial weed seed predators may encounter higher risk from the toxins produced by CRW Bt corn because they are in the same Coleopteran taxon as the target organism. Carabid beetles (Coleoptera: Carabidae) are generalist predators that search for prey, including seeds, at the soil surface of agricultural fields and adjacent habitats. I am focusing my research on assessing how CRW Bt and soil insecticides alter the composition and abundance of three species of non-target beetles and how in turn, this affects the weed suppression they provide to the agro-ecosystem. This research is part of a long-term, multidisciplinary cost-benefit analysis of these two pest management practices on non-target organisms providing ecosystem functions that includes nematodes, the soil microbial community, and soil-dwelling arthropods.

 

Stephanie Whitehouse

 

RESEARCH FOCUS

      The objectives of my research are to:

      (1) to document differences in weed pressure between cropping systems that vary in their nitrogen-saturation levels; and

     (2) investigate the effects of these differences in N-saturation levels on the incidence of disease affecting weeds and on subsequent weed growth and vigor.

 

Emily Hotchkiss

 

RESEARCH FOCUS

      The main goal of my research is to determine the influence of polyembryony (i.e., the production of multiple genetically-identical seedlings from a single seed) on seedling establishment success and growth in the exotic invasive vine, pale swallow-wort (Vincetoxicum rossicum syn. Cynanchum rossicum). I am also interested in examining the effect that light environment (forest gap versus forest shade) has on seedling/plant establishment and performance in this species. I am testing several hypotheses including:

·  pale swallow-wort seedling establishment and growth will be greater in exposed forest gaps compared with more shaded areas, and

·  the greater the number of seedlings from polyembryonic seeds the greater their establishment success and performance.

The research is being carried out in a forested section of the Robert Musgrave Agronomy Research Centre in Aurora, NY. Pale swallow-wort is very abundant and is expanding its range in this region of central New York State.

 

 

Brian Caldwell

 

RESEARCH FOCUS

      Brian is interested in all aspects of organic crop management. His current project is a comparison of four organic approaches to production of field and vegetable crops. The four systems include: one modeled on a successful organic farm with outstanding production and weed control; one with a variant on that system (higher nutrient additions in the field crops trial and an intensified cropping system in the vegetable trial); one that is similar to typical practices; and one with an experimental organic reduced tillage system using ridge till culture. The field crops trial also includes a conventionally-managed treatment. Crop yield and quality, insect levels, soil nutrients and health, and weeds are being monitored. The project is set to last for 4 years.

 

Dan Brainard

 

RESEARCH FOCUS

      The primary objective of my research is to develop integrated weed management systems which reduce reliance on herbicides without sacrificing farm profits. Most of my applied research has focused on the use of cultivation and cover crops for weed management in vegetable crops. More basic research has examined intraspecific variation in weed seed production, germination, and emergence patterns in annual cropping systems. Current research projects include:

·  Summer smother crops. Evaluation of varieties of forage cowpea and soybean for weed suppression, biomass production, and N-fixation under Northeast organic production systems; Impact of seeding rate and soil fertility on weed suppressive ability and N fixation efficiency of mixtures of legumes (soybean and cowpea) and non-legumes (buckwheat and sorgum sudangrass).

·  Intercropping vegetables and cover crops. Effects on weed management of interseeding cover crops (rye, vetch and oats) into brassica crops (cabbage, broccoli and kale) during cultivation operations; Impact of cover crops as nurse crops in slow-emerging vegetables.

·  Optimization of stale seed bed practices. Impact of abiotic factors (temperature and soil fertility) and methods of weed control (vinegar, flaming or cultivation) on effectiveness of stale seed beds.

·  Influence of N fertility on weed emergence. Effect of N fertilization rate, timing, and N-source on germination and emergence of multiple populations of Powell amaranth.

·  Maternal effects on weed seed characteristics. Impact of competition, N fertility, and drought stress during seed maturation on seed size, seed N content and seed germination.

·  Habitat correlated differences in weed seed characteristics. Microevolution of seed characteristics of Powell amaranth under different crop-rotation (perennial vs annual) and fertility management (organic vs inorganic N sources) systems.

 

Julie Major

 

RESEARCH FOCUS

      My M.S. work in Toni's group focused on the weed ecology of Terra preta (Black Earth) sites of the central Amazon. Terra preta soils are of anthropogenic origin, and are thought to have originated in semi-permanent Amerindian settlements in the prehistoric and early historic periods. Contrarily to the vast majority of soils from which they were derived and that surround Terra preta patches, the latter are black and contain large amounts of organic carbon, phosphorus (P), and calcium (Ca) (also see work by Prof. Johannes Lehmann in the Department of Crop and Soil Sciences). Local farmers value these soils because of their potential high productivity. In fact, Terra preta soils are often used to grow horticultural crops for market, a production system that one rarely encounters on surrounding oxisols. But, as one might expect, weed pressure tends to be greater on Terra preta soils.
      The basic questions I addressed in my research focused on the differences in weed biodiversity, crop yield reduction potential, and weed population dynamics on Terra preta soils versus surrounding soils. Weed and crop (corn) data was collected from experimental field trials established at four different locations near Manaus , Amazonas, Brasil. At each location, two paired plots were established, one on Terra preta and one on the surrounding, background soil. A complete list of weed species observed during this trial and in a survey of cropped plots on Terra preta can be found here.
      Another component of my research included assessing farm biodiversity as a function of market integration on Terra preta farms. I worked in collaboration with Profs. Charles R. Clement and Newton Falcão, at the National Institute for Research in the Amazon (INPA), Manaus, Amazonas, Brasil.
      My present research interests, in J. Lehmann's group, concern the ability of charcoal amendments to reduce nutrient leaching on highly weathered, acid soil, and to assess carbon dynamics with charcoal additions. I do fieldwork in the Llanos Orientales of Colombia, in collaboration with Marco Rondon at CIAT (www.ciat.cgiar.org).

 

Robert Nurse

 

FOCUS OF PhD RESEARCH

      My PhD research involves looking at how maternal environment influences the seed dormancy in velvetleaf (Abutilon theophrasti Medic.). The overall goal is to determine if velvetleaf individuals escaping weed control or germinating later in the growing season need to be controlled with herbicides. It is unknown whether velvetleaf growing under competition with corn and under longer photoperiods will have altered allocation to seed dormancy. The main factors being examined are:

·  Environment : corn vs. no corn

·  Corn planting date : Early May, Late May, Mid June

·  Weed transplant date : 14 DBE (days before corn emergence), 0 DAE, and 14 DAE

      It is hoped that these treatments will show the effect of photoperiod and competition on velvetleaf seed dormancy. It is hypothesized that plants growing under longer photoperiods and at a competitive disadvantage to the corn will allocate fewer resources to seed dormancy. If this is the case it will be less critical to control emergent weeds late in the season as they may be controlled with herbicides or tillage the following growing season.

 

CURRENT RESEARCH INTERESTS AND PROJECTS

·  Develop sustainable, economical, environmentally safe weed management strategies using integrated weed management principles in field and horticulture crops.

·  Engineer novel, more efficacious reduced risk weed control strategies for horticultural and fruit crops.

·  Understand the effect of biotic factors on emergence, growth, and population dynamics of agricultural weeds, including that of noxious, invasive and/or herbicide resistant populations.

·  Obtain a better understanding of the seed biology/ecology of agricultural weeds, with special emphasis on invasive or herbicide-resistant populations.

·  Better understand the ecology of weed populations in transitional and long-term organic rotational systems in relation to organic fertility amendments (i.e. compost and green manures) and sound IWM practices.

 

Larissa Smith

 

RESEARCH FOCUS

     My research focuses on determining the effects of arbuscular-mycorrhizal fungi (AMF) on the growth and competitive ability of the exotic invasive species pale swallow-wort (Vincetoxicum rossicum) [Asclepiadaceae]. My research makes use of both laboratory and field experiments with field trials established near Henderson Shores, NY just south of Lake Ontario. A collaborator on this project is Dr. Sigurdur Greipsson from the Department of Biological and Environmental Science, Troy State University, Troy Alabama.