The ecology and control of Patersons curse Echium Plantagineum L

Paterson's curse (Echium plantagineum L.) was introduced into Australia from the Mediterranean regions around the 1850s and is now widespread, especially in the south and east. In many areas, it is a dominant species in pastures and non-agricultural areas. However, the reasons for its widespread success have received little attention in the past. Two other Echium species, viper's bugloss (E. vulgare L.) and Italian bugloss (E. italicum L.), are also naturalized but are much less widespread. In overseas countries, viper's bugloss often is widespread whilst Paterson's curse and Italian bugloss, generally, are only incidental species. Opinions have been divided on the value of Paterson's curse as a forage species. Some farmers and Government bodies regard it as a serious weed and others consider it a useful pasture plant. This conflict is well-reflected in the contrasting common names, Paterson's curse and salvation Jane, given to the plant in the eastern states and South Australia respectively and has arisen, no doubt, because opinions have been based on casual observation rather than critical experimentation. Its condemnation by some as a weed has led to a pre-occupation with control, although most recommendations have advocated the use of herbicides and neglected other management factors. This study investigated some aspects of the physiology and ecology of Paterson's curse in order to provide critical information on the widespread success of the species in southern Australia, and on its fodder value. Farm management practices to control the plant, or minimize problems associated with its presence in pastures, also were investigated. The results of the study suggested that Paterson's curse is widespread and persistent in the Mediterranean-type climatic areas of southern Australia because: (i) seed germination occurs over a wide range of temperatures and is favoured at high temperatures, (ii) seed dormancy is well-developed and allows seed from a single seed crop to germinate sporadically over several years, (iii) seedlings mostly emerge with late summer and early autumn rains, (iv) seedlings are well-adapted to survive during moisture stress, (v) seedlings have a high relative growth rate, (vi) plants are responsive to nitrogen and phosphorus, (vii) plants are not suppressed by competition from sub clover, (viii) plants are not heavily infested and damaged by insects, (ix) plants are persistent and productive when grazed, and highly productive in the absence of grazing, (x) flowering is stimulated by low temperatures and/or long photoperiods, (xi) seed production is high, especially in the absence of grazing, (xii) seeds are readily dispersed by grazing animals and in grain and fodder. Where Paterson's curse is considered a weed, it can be controlled in any year by the use of herbicides, the establishment of competitive species, and the management of grazing stock. However; control measures must be continued and seeding prevented for many years before the plant can be eradicated because well-developed seed dormancy ensures persistence despite failure to seed in any year. In pastures, Paterson's curse is a useful species because it is persistent, highly productive, nutritious, and readily eaten by stock. Moderate grazing during the year is adequate to maintain pasture balance and prevent Paterson's curse from becoming dominant, -rank, and objectionable. Spraying with herbicides to control the plant seems unnecessary because it is expensive', reduces total herbage production, and generally gives only temporary control. On roadsides and waste areas, where grazing pressure is low, the plant may be dominant in some years (e.g. early or false break years) and virtually absent in others (e.g. late break years). Such variation in plant numbers is dependent on climate, independent of man, and typical of many annual, volunteer species. Such non-agricultural infestations are unlikely to spread into surrounding agricultural land that is moderately grazed or cultivated, or undisturbed bushland where soil nitrogen and phosphorus are low, especially if dispersal is not assisted by man. Whether control is necessary in these non-agricultural situations is largely subjective, and depends on the vegetation management policy of the area. However, there seems no reason why Paterson's curse should not be accepted as part of the naturalized vegetation in disturbed, non-agricultural areas