Sentence:  In a second instance, two parasitic fungi ("Dicyma pulvinata" and "Cylindrosporium concentricum") were introduced against a fungal pathogen causing black crust on the foliage of rubber, "Phyllachora huberi", in the Amazon basin of Brazil and long-term control was documented [...]. These antagonists are obligate pathogens living as <WSD>hyperparasites</WSD> and their increase is dependent on the presence of the plant pathogen. 
Meaning of the word marked with <WSD> tags:  Any parasite whose host is a parasite.