UNLABELLED • PREMISE OF THE STUDY Local adaptation in plants often involves changes in flowering time in response to day length and temperature. Many crops have been selected for uniformity in flowering time. In contrast, variable flowering may be important for increased competitiveness in weed species invading the agricultural environment. Given the shared species designation of cultivated r...

Abstract: Increased crop density and use of herbicides are two important components of integrated weed management program in wheat but no much information is available on combined effects of these two treatments. A field experiment was conducted to determine the interaction effect of increasing seed rates and weed management treatments on monocot and dicot weeds, grain and straw yield and uptak...

Among agricultural pesticides, herbicides comprise the most employed group in agriculture. The main function of these chemicals is to control weeds, weed competition reduces produc‐ tivity, without significantly impacting crop yield. Weeds tend to compete with crops by extracting essential elements from the soil, water, intercepting light and CO2, interfering in the culture development and affe...

A review of organic growers' concerns about weeds is presented and several issues that may ease those concerns are highlighted. The underlying principles of organic weed management (OWM) are briefly discussed and results from organic grower surveys regarding weed management practices in organic horticultural cropping are presented. The most common weeds encountered by organic growers, often tho...

■ Abstract Bees are generally regarded as beneficial insects for their role in pollination, and in the case of the honeybee Apis mellifera, for production of honey. As a result several bee species have been introduced to countries far beyond their home range, including A. mellifera, bumblebees (Bombus sp.), the alfalfa leafcutter bee Megachile rotundata, and various other solitary species. Poss...

Loblolly pine (Pinus taeda L.) seedlings were grown in competition with native weeds using soil and seed bank collected from recently chopped and burned areas near Appomattox, Virginia. One-year-old seedlings were planted and weeds allowed to germinate from the native seed bank while being exposed to CO(2) (ambient and elevated - approximately 700 ppm) and water (water stressed and well watered...

The identification and classification of weeds are of major technical and economical importance in the agricultural industry. To automate these activities, like in shape, color and texture, weed control system is feasible. The goal of this paper is to build a real-time, machine vision weed control system that can detect weed locations. In order to accomplish this objective, a real-time robotic ...

UNLABELLED • PREMISE OF THE STUDY The evolution of invasiveness has been extensively studied in natural ecosystems; however, far less is known about the evolution of agricultural invasiveness, despite the major economic impact of weeds on crop productivity. Examining the population structure of recently arisen weeds can provide insights into evolutionary avenues to invasion of agroecosystems....

It has been suggested that genetically modified herbicide-tolerant crops may benefit biodiversity because spraying of crops may be delayed until later in the growing season, allowing weeds to grow during the early part of the year. This provides an enhanced resource for arthropods, and potentially benefits birds that feed on these. Thus, this technology could enhance biodiversity. Using a revie...

The use of molecular techniques is rapidly growing as the tools have become more diverse and powerful, more widely available, and easier to implement. Molecular analyses are able to elucidate information about target weeds that is critical to improving control success, such as taxonomic clarification, evidence of hybridization and cryptic species, better development of test plant lists, populat...