Atrazine fruit crops

Just as atrazine is important in com, simazine is a pre-emergence triazine that provides broad-spectrum residual weed control in many of the important fruit and nut crops when applied either alone or in combination with a contact product such as glyphosate to control weeds at the time of application (Figure 1.5). 

Although simazine was the first triazine to be developed and marketed in corn as well as other crops, the more versatile atrazine quickly became the standard herbicide in corn. Simazine, however, has remained very valuable and is important on forage crops, ornamentals, turf, and several other vegetable, fruit and nut crops, including almond, apple, artichoke, avocado, berries, cherry, citrus, grape, hazelnut, peach, and walnut. There also remains a strong demand for simazine use in corn in some areas based on specific weed pressure. Simazine is manufactured and sold by several companies today in more than 25 countries around the world, with Brazil, the United States, Australia, and Japan ranked as the top four. 

Atrazine and Oil In the western part of the Com Belt and the Great Plains, the agricultural extension service promoted the practice of applying a mixture of a lower rate of atrazine and oil in an early postemergence spray (when weeds hrst appeared). A highly refined crop oil was used, similar to that used in fruit-tree sprays. The practice was adopted extensively, especially in the Northern states to reduce the cost of herbicide treatment and lessen the potential for carryover. 

Simazine was the main product studied in early research on the triazines for weed control in tree fruits and vineyards (Doll, 1960 Larson and Ries, 1960). On mature grapevines in a deep, fine, and sandy loam soil, no differences in crop tolerance were observed between simazine and atrazine (Leonard and Lider, 1961). However, subsequent studies indicated that grapevines were more tolerant to simazine than to atrazine (Lange et al., 1969a). Prometryn was intermediate between the two in terms of crop tolerance (Lange et al., 1969a). 

Many triazines have been evaluated for weed control in orchards and vineyards, but primary emphasis will be placed on simazine as the herbicide of preference in most of these crops. In general, simazine is better tolerated by most tree fruits, nuts, and vines than high rates of atrazine, prometryn, propazine, terbutryn, terbuthylazine, or metribuzin. 

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