Antifungal effect and chitinase activities of the froth of spittlebug Poophilus costalis (Walker) (Hemiptera: Cercopoidea: Aphrophoridae)

Abstract

Nymphs of xylophagous spittlebug Poophilus costalis (Walker, 1851) produce froth that covers their entire body surface. However, no mold has ever been found on this froth under natural conditions. This study has shown that the froth of P. costalis can repress the growth of Fusarium oxysporum f. sp. pisi. Three chitinases, i.e., beta-N-acetylglucosaminidase, chitobiosidase, and endochitinase, with specific activities of 1.759, 0.365, and 1.172 U/mg protein, respectively, and a protease with minimal activity have been detected in this froth. beta-N-actylglucosaminidase activity was also detected in the source of the froth, the nymphal Malpighian tubules and the host plant Commelina diffusa Burm. f. These findings suggest that the antifungal effect of the froth from P. costalis may be attributed to the chitinase produced by its Malpighian tubules and/or its host plant.