Verticillium dry bubble, recently named Lecanicillium fungicola, is a mycoparasite that attacks white button mushrooms (Agaricus bisporus), among other hosts, during its generative period.
Dry bubble follows the typical verticillium life cycle, although insect vectors play a large role in the spread of this disease.
L. fungicola is a devastating pathogen in the mushroom industry and causes significant losses in the commercial production of its main host A. bisporus.
[2] Dry bubble mainly affects three different species of mushrooms: Agaricus bisporus, A. bitorquis, and Pleurotus ostreatus.
[4] On the other hand, it has been recently shown that very high populations of spores applied to the compost before casing can induce disease development.
Management and control of dry bubble disease relies mainly on hygiene and prevention of introducing inoculum on mushroom farms.
Prevention of mites and flies can help eliminate the spread of the pathogen throughout the crop, because whiteflies and springtails are capable of transporting spores from infected to healthy mushrooms.
[6] Casing mixture should be prepared and stored in a clean room away from mushroom wastes, outside soil, insects, and rodents help prevent introduction of the pathogen to the crop.
Teaching harvesters and workers to identify and treat dry bubble disease is a practice that will reduce or eliminate the level of inoculum.
[3] The only effective and currently legal chemical control for dry bubble disease is Sporgon (active ingredient: Prochlorax-Manganese).
While there are still necrotic lesions present on the cap surface of the brown partial resistant cultivar there has been shown to be less hyphae and sporulation.
[2][3] Anaerobic conditions and high temperatures may both be achieved by heated composting of casing and debris which is removed from the growing area in order to eliminate viable spores.
[5] Another function of 1-octen-3-ol, is that application stimulates growth of bacterial populations in the casing and of the Pseudomonas spp., demonstrated to play part in the onset of mushroom formation in A.
[5] Environmental conditions within the growing area can greatly affect the rate of growth and spread of dry bubble.
This coincides with environmental preferences of white button mushroom, its primary host, which favors a RH of 85% and warm temperatures of 25 °C.
[3] If dry bubble infects and is left uncontrolled in the mushroom growing environment, the disease can wipe out an entire crop in 2–3 weeks.
[7] However, literature on dry bubble has been published in India as early as 1960, proving that it has been an economic problem for mushroom growers during much of the 20th century.
[3] Because few fungicides are effective and even fewer are legal, dry bubble is likely to remain the most critical disease to mushroom growers in Europe and North America in the future unless breakthroughs in research are made.