Brazilian pusley (Richardia brasiliensis) is one of the most important weeds infesting orchards, crops and pastures in South America. Frequently, their populations are dense enough to promote significant losses to the farmers. In the studies on the biology and control of the weeds, the leaf area determination is fundamental, but commonly requires sophisticated and expensive equipment or destructive techniques. So, the present research was set up aiming to obtain a suitable equation for R. brasiliensis leaf área estimation from the linear leaf measures, such as the leaf length in the mid rib direction (C), the maximum leaf width (L), and the rela tion CxL. The measures were done in 500 leaves collected from plants infesting different places and crops and showing suitable nutritional and health conditions. All the equations, linear, geometric, and exponential, permitted suitable estimates of the R. brasiliensis leaf area (AF). The suggested equations was AF = 0.5899 (CxL), because it is easy to use, showed the smallest Stand Error, and the determination coefficient was high, R2=0.9886.
Richardia brasiliensis; weed; leaf area