Resistencia de malas hierbas a herbicidas en el cultivo del arroz y en cultivos leñososestudios de mecanismos de resistencia

Résumé

The use of herbicides to control weeds is currently threatened by the emergence at an exponential rate of resistant weed biotypes. These resistant weeds represent an important problem for the farmer who observes how their fields grow uncontrollably and produce a reduction in the yield of their crops, even though they had been satisfactorily controlled before. An incorrect application of the herbicides, and the tendency to use monocultures, is aggravating this problem, because plants that show multiple resistance to several herbicides at the same time are emerging both in Spain and in other regions of the world. This leaves the farmer with no alternative to exercise chemical control of the weeds. An adequate handling of the resistances entails prospecting in areas where there is a suspicion of failures in the control with herbicides, tests to determine if there is resistance and, finally, the study of the mechanism responsible for this resistance, in order to develop control systems alternative. This thesis has worked with three genera of weeds that grow in woody crops (“Conyza spp”) and rice (“Echinochloa spp” and “Leptochloa spp”). For each of them, resistant biotypes have been identified, the degree of resistance has been determined by dose response trials and the mechanisms responsible for this resistance have been studied. Integrated weed control is advised by combining chemical control and non-chemical control.