Fumaria officinalis (common fumitory)

In northern temperate climates, there is a particular need for active control of F. officinalis in the annual spring-sown crops. In warmer temperate or subtropical climates, particularly where summers are dry and winter germination is frequent, control is needed mainly in autumn-sown crops. The species is resistant to many of the herbicides in use, particularly those of the phenoxy acetic acid group, and this resulted in an increased abundance of this species in many agricultural areas after 1950 (Stuanes, 1972; Gummesson, 1979). Diclorprop and mecoprop have been used more or less successfully in the control of F. officinalis, but today it is mainly controlled by bentazone, chlorsulfuron or tribenuron-methyl in cereals and other crops where these chemicals can be used (Ericsson, 1997). There is always a need for active control (mechanical or chemical) of the species when it occurs abundantly in vegetable and other row crops with a low competitive ability. In southern European countries F. officinalis appears to be favoured by direct drilling rather than sowing after conventional tillage, such that direct drilling results in an increased need for chemical control (Fernandez-Quintanilla et al., 1984). Perennial fodder crops, for example, clover-grass leys in a crop rotation, disadvantage this annual weed, and may provide some control. Pasture and fodder crops which form dense stands with little bare ground effectively reduce establishment opportunities, and may be important aspects of integrated management programmes.

In summer crops, sown in early spring, F. officinalis may become very competitive, requiring effective control. In crops sown or planted at wide row spacings and therefore weakly competitive (root crops and vegetables), it can reduce yields very severely if not effectively controlled. Individuals that emerge in late spring and early summer are not restrained by early control measures and can compete and become troublesome in these crops. F. officinalis is usually not a problematic weed in perennial fodder crops, but can sometimes grow vigorously in patches with weak crop plants, where it can be harmful because of its low fodder quality.