Six species of insects and a rust fungus have been successfully established for biocontrol of the weed Parthenium hysterophorus L. in Queensland, Australia. Effectiveness of biocontrol insects was evaluated at two properties in Queensland during 1996-97 based on an exclusion experiment using insecticides. Parthenium-infested plots with and without biocontrol insects were sampled at monthly inte...

Currently, the UK has no procedure for the approval of novel agricultural practices that is based on environmental risk management principles. Here, we make a first application of the 'bow-tie' risk management approach in agriculture, for assessment of land use changes, in a case study of the introduction of genetically modified herbicide tolerant (GMHT) sugar beet. There are agronomic and econ...

A field experiment was conducted during the seasons of 2010/2011 in a semiarid savannah zone, at the faculty of agriculture demonstration farm University of Zalingei two kilometers east of Zalingei town Western Darfur State. The aim of the experiment is to study the effect of weed control on growth and seed production of (Clitoria ternatea) under rainfed conditions. Four treatments viz.; No wee...

in this study, the effects of weed control treatments and plant density on lentil (lens culinaris) yield and yield components as well as weed control efficacy were investigated. the study was conducted according to a split-plot arrangement based on randomized completely block design in three replicates in karaj in 2007-2008. the weed control chemical treatments in four levels (trifluralin herbi...

A simple model is developed in which the density of weed seedlings emerging in a field is related to (1) the ability of seedlings to emerge from various depths in the soil, (2) the survival of seeds at different depths, and (3) the depth of seed burial in no tillage, rotary tillage, and plow tillage. Other tillage regimes are considered by analogy. Literature is reviewed to determine biological...

BACKGROUND One theoretical explanation for the relatively poor performance of Brassica rapa (weed) x Brassica napus (crop) transgenic hybrids suggests that hybridization imparts a negative genetic load. Consequently, in hybrids genetic load could overshadow any benefits of fitness enhancing transgenes and become the limiting factor in transgenic hybrid persistence. Two types of genetic load wer...

The eco-evolutionary mechanisms of biological invasions are still not thoroughly understood. Alligator weed, Alternanthera philoxeroides (Martius) Gisebach (Amaranthaceae), is a plant native to South America and a weed in Australia and other countries. To better understand its success as an invader, we assessed the morphological and cytogenetic variability of 12 Argentine populations and the cy...

Loblolly pine (Pin1r.s tae(/(i L.) seedlings were grown in co~npetition with native weeds using soil and seed bank collected from recently chopped and burned areas near Appornattox, Virginia. One-year-old seedlings were planted and weeds allowed to germinate from the native seed bank while being exposed to COz (ambient and elevated approximately 700 ppm) and water (water stressed and well water...

Soybeans are subject to potential contamination from toxic weed seeds during harvest, transportation and storage. The more common foreign seeds include those from jimsonweed, cocklebur, nightshade, cowcockle, corncockle, morning glory, castor, pokeweed, and crotalaria. This review addresses itself to the chemistry and toxic principles of these contaminants. Since jimsonweed seeds are probably t...

Variation in the effectiveness of biocontrol agents on the weed Parthenium hysterophorus L. was evaluated at two properties (Mount Panorama and Plain Creek) in Queensland, Australia for four years (1996-2000) using a pesticide exclusion experiment. At Mount Panorama, higher levels of defoliation by the leaf-feeding beetle Zygogramma bicolorata Pallister and galling by the moth Epiblema strenuan...