Friday Fungus: Pleospora papaveracea and the war on drugs

My mycological fascination button was activated by this little posting from Al Jahom about research into using Pleospora papaveracea (and other mold-like fungi) as a biological agent to control opium poppy production back in 2000. And recent reports on a serious fungal infection of Afghan poppies! Some of the research abstracts are here and one concludes that:

In the field, P. papaveracea was more consistent in its effects on opium poppy from a local seed source designated Indian Grocery. P. papaveracea caused higher disease ratings, more stem lesions, and equal or greater yield losses than did D. penicillatum on Indian Grocery. The late-maturing opium poppy variety White Cloud was severely damaged by disease, regardless of formulation or fungal treatment. P. papaveracea was the predominant fungus isolated from poppy seed capsules and the only fungus reisolated from the field the following year. These studies provide a better understanding of the infection process and the differences between these two pathogenic fungi and will be beneficial for the development of the fungi as biological control agents.

There is no doubt that P. papaveracea is effective against opium poppies – especially when the plants are young and the Afghan growers’ description of the disease affecting their crops is consistent with a mildew-like fungal infection. P. papaveracea is a natural parasitic fungus of poppies native to central Asia – not the product of genetic engineering or manipulation.

However, there will always be concerns about the deliberate introduction of biological agents – even naturally occurring ones – to a given environment in terms of secondary effects as well as impacts on human health. There is no confirmation that the Afghan reports are the result of deliberate human action and it could be a natural outbreak of an existing fungus. Indeed, the outbreak could be effectively controlled (I suspect) through the use of the aerial spraying techniques used to control fungal and pest threats to less controversial crops.

Similar fungal agents are being developed to control coca and marijuana production and recently Peru has passed a law banning the use of biological agents in coca eradication. Also – as has been the case with apples and roses – breeding programmes are likely to result in disease resistant varieties.

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