The most common cause of bronchopulmonary aspergillosis is

Aspergillus fumigatus is responsible for most cases of invasive aspergillosis including bronchopulmonary aspergillosis,almost all cases of chronic aspergillosis,and most allergic syndromes.A.flavus is more prevalent in some hospitals and causes a higher propoion of cases of sinus and cutaneous infections and keratitis than A.fumigatus.A.Niger can cause invasive infection, but more commonly colonizes the respiratory tract and causes external otitis.A.terreus causes only invasive disease,usually with a poor prognosis.A.nidulans occasionally causes invasive infection,primarily in patients with chronic granulomatous disease. Reference:Harrison's medicine-18th edition,page no:1655.