This study aimed to evaluate the weed population and its critical period of competition with physic nut plants eight months after transplanting. The experiment was established in a randomized block design in a factorial scheme composed by three provenances and five periods of coexistence and of weed control (0, 90, 180, 270, and 360 days) with three replications. The importance value index was quantified to characterize the weed population. The critical period was determined by PAI (period before interference), PTPI (total period of interference) and CPIC (critical period of weed control) according to the variables: stem diameter, crown diameter, number of branches and plant height. Maximum admitted losses were 5 and 10% of each measured variable. Weed species in decreasing order of importance were Sorghum halepense L. Pers., Commelina virginica L., Sida rhombifolia L., Brachiaria plantaginea (Link) Hitch, Euphorbia heterophylla L., Cenchrus echinatus L. and Boerhavia diffusa L. Physic nut plants are subject to reduction of their morphometric measures of stem diameter, crown diameter, number of branches and plant height by weed interference.
Jatropha curcas L.; growth; competition
