Potential Biological Control of Opium Poppy by Fungal Pathogens

Papaver somniferum (Opium Poppy) contains several opiates used for their pharmacological properties in both legal and illicit drug manufacturing. These compounds include but are not limited to morphine, codeine, and thebaine. Pharmacologically, these compounds are used to elevate the pain threshold, as well as altering an individual's reaction to pain. These compounds are also very useful as cough depressants and powerful sedatives. The pathogenicity of Crivellia papaveracea and Brachycladium papveris, pathogens of Papaver somniferum, was determined on species and cultivars in the genus Papaver, a major field crop, and in plants in related genre including P. somniferum and P. bractearum Plant Introductions (PI). These pathogens exhibited high specificity to their host range, infecting only two of 13 additional Papaver spp. Other close relatives and unrelated species were not susceptible to infection. Little resistance was found in the PI lines and in a large collection of opium poppy germplasm. Crivellia papaveracea was uniformly more virulent as a pathogen to the plants and germplasm than Brachycladium papveris. The study indicates that it is not likely that the host range of this pathogen extends beyond the genus Papaver, and that there is little resistance to the disease in a geographically diverse opium poppy germplasm collection. The limited host range of the pathogens and the high susceptibility of the host identifies the pathogens as potential candidates for development as mycoherbicides against illicit poppy fields. This suggests the potential for controlling illegal Papaver somniferum populations that are used as a source of heroin, without jeopardizing legally grown cultivars used for legitimate medicinal uses.