Transmission potential of the entomopathogenic fungi Isaria fumosorosea and Beauveria bassiana from sporulated cadavers of Diaphorina citri and Toxoptera citricida to uninfected D-citri adults

Diaphorina citri Kuwayama (Hemiptera: Liviidae) is the vector of the causal agent of Huanglongbing disease, and Toxoptera citricida Kirkaldy (Hemiptera: Aphididae) is the vector of the citrus tristeza virus. D. citri and T. citricida share the same habitat and both are susceptible to Beauveria bassiana and Isaria fumosorosea. Therefore, the aim of this study was to evaluate the horizontal transmission of B. bassiana ESALQ-PL63 and I. fumosorosea ESALQ-1296 between D. citri cadavers and uninfected D. citri adults, as well as between T. citricida cadavers and uninfected D. citri adults under laboratory and semi-field conditions. In the laboratory, the presence of one to ten D. citri cadavers infected with B. bassiana and I. fumosorosea in citrus plants resulted in mortality rates of D. citri adults ranging from 51.2 to 81.9 % and 36.2 to 68 %, respectively. When T. citricida cadavers were used, the mortality rates of uninfected D. citri adults ranged from 35.4 to 87.7 % with B. bassiana and from 41.7 to 80.4 % with I. fumosorosea. The horizontal transmission was also confirmed under semi-field conditions. The results indicate that the control of D. citri using I. fumosorosea and B. bassiana can be promoted through conidial cycling in T. citricida, by generating new infection cycles, which may contribute to the overall performance of microbial control in citrus.