Armillaria Root Rot: Biology and Control of Honey Fungus

This book aims to answer the questions most often raised about Armillaria. Members of this genus include some of the most virulent pathogens which kill and decay trees, shrubs and vines. One of the most virulent is Armillaria mellea, the honey fungus, which causes serious root and butt rots in woody plants. Starchy-rooted plants, including some valuable herbaceous plants, and several weeds can also be killed.

Armillaria mellea is reputed to be by far the most serious plant disease in British gardens. This, and related species, are common in forests, orchards and gardens throughout the world. At the same time, the genus attracts worldwide interest in their highly evolved biological adaptations, potential pharmaceutical properties and, not least, culinary qualities.

Generations of mycologists first thought that only one major species, Armillaria mellea, existed, but this has now been divided into at least six species in Britain. There are known to be many other species worldwide, in temperate Africa, the Americas, Australasia and other parts of the tropics. In temperate Eurasia three species are known to be serious pathogens.

Diagnosis is difficult as not only do the fruiting bodies differ subtly in morphology between species, but they also often differ between genets within one species. However, tests have now been developed using molecular techniques and these diagnoses can be done within hours. The physical methods recommended to control the fungus, once established, are extremely laborious, and mostly impractical, but any control technique will only work best at the earliest stages of infection, making accurate diagnosis vital.

This book is of interest to horticultural growers, gardeners, arboriculturalists, foresters, and plant pathologists, for whom Armillaria represents the ultimate fungal foe but, like many adversaries, it should also elicit admiration, albeit grudgingly, as a supreme plant pathogen.

Roland T. V. Fox is Emeritus Professor, University of Reading.