Solanum americanum is a very aggressive weed that, besides competition, can cause many other problems. Despite being one of the most important parameters to be analyzed, only few studies have been carried out concerning the leaf area mainly because its determination demands sophisticated equipment or destructive techniques. Aiming to develop equations that allow to estimate the leaf area of this weed using linear measure of the leaf surface, statistical relations between the leaf area and the following linear measures were determinded: the leaf lenght in the mid rib direction (C), maximum width (L) and the product (C x L). 200 leaves were collected from plants infesting different places and crops and showing suitable nutrition; and health conditions. All the equations, linear, geometric and exponential permitted suitable estimates of the Solanum americanum Mill leaf area (Af) . From the point of view of pratice, the linear equation (C x L) was selected because it shows the Smallest Stand Error. Thus, a estimative of Solanum americanum. Leaf area can be calculated by the equation Af = 0.5632 x (C x L), with R2 = 0.9516.
weed