Cultivation of lowbush blueberry (Vaccinium angustifolium Aiton), an important crop in the eastern part of North America, is unique, as it is carried out over the course of two consecutive growing seasons. Pest management, particularly weed management, is impacted by this biennial cultural practice. The choice of methods to control weeds is narrow, and such a system relies heavily on herbicides for weed management. Availability of unique herbicide active ingredients for weed management is limited, and available herbicides are used repeatedly, so the risk of developing resistance is acute. Hair fescue (Festuca filiformis Pourr.), a perennial grass weed, has evolved resistance to hexazinone, a photosystem II inhibitor frequently used in lowbush blueberry production. We show that substitution of phenylalanine to isoleucine at position 255 is responsible for a decreased sensitivity to hexazinone by a factor of 6.12. Early diagnosis of resistance based on the detection of the mutation will alert growers to use alternative control methods and thus help to increase the sustainability of the cropping system.

This paper gives an overview of computer assisted molecule design using quantitative structure activity relationships (QSAR). In deriving a QSAR for a set of compounds, one should be aware of possible properties one can use to correlate with the activity of this set of compounds. The paper describes some of the traditional and also more recently used properties that can be calculated. The traditionally used properties have been those calculated for the substituent groups that were varied on a particular scaffold, whereas the more recently used properties are those calculated on the molecule as a whole. One of the most recently used properties for comparative purposes are fields around the molecules. The technique is termed comparative molecular field analysis (CoMFA). The statistical techniques used to correlate the properties with the activity are also described and, finally, a case study is described. The case study shows the application of traditional and 3D QSAR (CoMFA) techniques on some photosystem II inhibitors.