Blubaugh, Carmen K. Ph.D., Purdue University, May 2015. Undercover Predators: Vegetation Mediates Foraging, Trophic Cascades, and Biological Control by Omnivorous Weed Seed Predators. Major Professor: Ian Kaplan. Weed pressure is the most costly challenge that vegetable growers face, requiring more labor investment than other production inputs. Vertebrate and invertebrate seed predators destroy...

Increasing concerns about the environmental impacts of herbicides, the development of herbicide-resistant weeds, and the need to carefully weigh costs and benefits have led to greater interest in developing rational, economical, and sustainable approaches to weed management (O'Donovan 1996). In addition, greater emphasis on post-emergence applied herbicides such as glyphosate has allowed for mo...

An investigation was made to see the salt tolerance of 10 weed species of rice. Properly dried and treated seeds of weed species were placed on 9 cm diameter petridishes lined with Whatman No. 1 filter paper under 6 salinity regimes, viz. 0 (control), 4, 8, 16, 24 and 32 dS m(-1). The petri dishes were then kept in germinator at 25 +/- 1.0 degrees C and 12 hr light. The number of germinated see...

Historically, pasture breeders have not considered environmental weed risk in species selection and assessment. Consequently several pasture or former pasture species are now problematic environmental weeds in Australia. The CRC for Plant-Based Management of Dryland Salinity (CRC) has taken a pro-active approach to prevent further introduction or promotion of weedy pasture species by developing...

Weed control is generally the first major decision to be made once alfalfa has germinated. Managing weeds in a timely manner is necessary to provide maximum production of high quality alfalfa hay. A poor weed management decision can lead to stand loss, poor quality hay, unacceptable weed control, alfalfa injury and a loss of money. Herbicides are applied to 75% of newly planted alfalfa in Calif...

The genetic basis of weedy and invasive traits and their evolution remain poorly understood, but genomic approaches offer tremendous promise for elucidating these important features of weed biology. However, the genomic tools and resources available for weed research are currently meager compared with those available for many crops. Because genomic methodologies are becoming increasingly access...

The term weed is referring to plants used as culinary herbs and medicinal plants as well as ecologically adaptive and invasive segetal plants. In Europe, pollen of ragweed, mugwort, English plantain and pellitory are the main elicitors of weed pollen allergies. Presently, 35 weed pollen allergens have been identified. The most relevant belong to the protein families of pectate lyases, defensin-...

Chemical control ofweeds has increased agricultural productivity, but complete reliance on chemicals has serious drawbacks. These include high cost per acre, decreasing effectiveness, negative effects on plant community diversity, and increased opportunities for environmental contamination. One alternative is biocontrol, the use ofbiologicalfactors that naturally limit weed populations. Long-te...

Studies are presented on new types of anaerobic digesters in which chopped or dry crushed Ipomoea carnea was fed without any other pretreatment, in an attempt to develop commercially viable means of utilizing the otherwise very harmful plant. Two types of solid-feed anaerobic digesters (SFADs) were studied. The first type had a single vessel in which the bottom 35% portion was separated from th...

This paper describes the modeling of a weed infestation risk inference system that implements a collaborative inference scheme based on rules extracted from two Bayesian network classifiers. The first Bayesian classifier infers a categorical variable value for the weed–crop competitiveness using as input categorical variables for the total density of weeds and corresponding proportions of narro...