Implications of increasing labour costs and the development of herbicide resistance for profitable weed management in Philippine rice farming systems are investigated. The study employs RIMPhil (Resistance and Integrated Management in the Philippines), a bioeconomic simulation model developed to provide a comprehensive assessment of integrated weed management programmes for the control of annua...

In his News Focus article "GM crops in the cross hairs" (26 Nov., p. 1662), Dan Ferber refers to the assessment by Charles Benbrook of the effect that the introduction of Roundup Ready crops has had on herbicide use, concluding that the benefits are not clear-cut. We disagree with this conclusion. Changes in herbicide use are largely meaningless unless relative environmental and health risks ar...

Triazine herbicides inhibit photosynthesis by blocking electron transport in photosystem II. The target site of the herbicide was identified as a chloroplast thylakoid polypeptide (the Q B protein) o f 32,000 daltons. Studies o f triazine-resistant weed biotypes suggested that a subtle change in the QB protein caused the resistance. We have cloned the chloroplast gene (psbA) that codes this pro...

Farmland biodiversity is an important characteristic when assessing sustainability of agricultural practices and is of major international concern. Scientific data indicate that agricultural intensification and pesticide use are among the main drivers of biodiversity loss. The analysed data and experiences do not support statements that herbicide-resistant crops provide consistently better yiel...

BACKGROUND Barnyardgrass (Echinochloa crus-galli) is an important weed that is a menace to rice cultivation and production. Rapid evolution of herbicide resistance in this weed makes it one of the most difficult to manage using herbicides. Since genome-wide sequence data for barnyardgrass is limited, we sequenced the transcriptomes of susceptible and resistant barnyardgrass biotypes using the 4...

The herbicide terbuthylazine is widely used within the EU; however its frequent detection in surface and groundwater, together with its intrinsic toxicological properties, may pose a risk both for human and environmental health. Organic amendments have recently been proposed as a possible herbicide sorbent in soil, in order to limit herbicide movement from soil to water. The environmental fate ...

Herbicide rotations and mixtures are widely recommended to manage herbicide resistance. However, little research has quantified how these practices actually affect the selection of herbicide resistance in weeds. A 4-yr experiment was conducted in western Canada from 2004 to 2007 to examine the impact of herbicide rotation and mixture in selecting for acetolactate synthase (ALS) inhibitor resist...

Differences on response of mathematical models on herbicide leaching in the environment can occur due to the models and their limitations, mainly when using soil lysimeters. Tebuthiuron is a herbicide used in sugarcane crop and is applied in the recharge area of the Guarany aquifer in Brazil, one of the largest in the world. This study was conducted to compare the leaching potential of the herb...

Microorganisms decompose herbicides and they may serve as bioindicators of soil changes following herbicide application. Certain microbial species may be used as bioherbicides. This study has shown that Azotobacter is most sensitive to herbicide application; it is, therefore, a reliable indicator of the biological value of soil. The numbers of this group of nitrogen-fixing bacteria decrease con...

Pine voles (Microtus pinetorum) and meadow voles (Microtus pennsylvanicus) were studied in a commercial apple orchard in the Hudson Valley of New York during April and May 1981. Selected voles were given miniature radiotransmitters and then tracked before and after herbicide application. A total of eight pine and meadow voles were tracked throughout the experimental period. H0m.e range size dec...