Assessment of Two Novel Host-Derived Beauveria bassiana (Hypocreales: Cordycipitaceae) Isolates Against the Citrus Pest, Diaphorina citri (Hemiptera: Liviidae)

Abstract

The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Liviidae), vectors ‘Candidatus Liberibacter spp.’, the causative agent of Citrus Greening Disease (CGD) or Huanglongbing (HLB). Managing populations of psyllids in the Lower Rio Grande Valley (LRGV), TX, United States is imperative given a continuous increase in HLB-positive trees. A component of integrated pest management (IPM) program is the use of strains of entomopathogenic fungi for the biological control of D. citri. In an attempt to find endemic strains of entomopathogenic fungi that grow favorably under LRGV environmental conditions and naturally infect D. citri, psyllids were collected from local residential areas, surface sterilized, and plated on a semi-selective agar medium. Collection of over 9,300 samples from 278 sites throughout the LRGV led to the positive identification of two Beauveria bassiana (Balsamo-Crivellii) Vuillemin (Hypocreales: Cordycipitaceae) isolates, ACP18001 and ACP18002. Chi-square analysis of primary and secondary acquisition bioassays revealed that both field isolated strains outperformed Cordyceps (Isaria) fumosorosea (Wize) (Hypocreales: Cordycipitaceae) Apopka97 under both primary (direct spray) and secondary acquisition (adult exposure to sprayed foliage) bioassays with ACP18002 marginally outperforming ACP18001 under secondary acquisition. Slopes of the dose response regression lines for the three fungi were not significantly different. In addition, the thermal profiles for vegetative growth of each isolate indicated that the field isolates grew at higher rates than the standard at higher temperatures. The new isolates may prove to be good candidates for the management of D. citri populations in the LRGV.

Use and perspective of entomopathogenic fungi biocontrol agents of Asian citrus psyllid (Diaphorina citri): A bibliometric review

“…Investigating the results found through bibliometric analysis and the data presented in each research, we found that some of them were developed through the isolation of fungi native to the region where the studies were carried out, obtained by collecting naturally infected psyllid cadavers in the field, subsequently performing the morphological and genetic characterization, as well as the identification of the isolated fungi. Among eight researches initiated in this way, six were carried out in China, with the other two coming from the United States and Mexico (Lu et al, 2015;Awan et al, 2021a;Awan et al, 2021b;Qasim et al, 2021;Cisneros et al, 2022;Luo et al, 2022;Yan et al, 2022). This procedure reinforces the importance of considering the specificity of each isolate, in addition to the species of entomopathogenic fungus recommended for control and the geographic region from which the isolate originates, depending on the environmental conditions favorable for the fungus development.…”

“…This may have been due to the larger size of the experimental units used in the field, environmental conditions and higher temperatures, humidity variation, wind, and rain. In the study byGandarilla-Pacheco et al (2013), nymphs of D. citri sprayed with a suspension of C. fumosorosea showed higher mortality (84.2%), while nymphs sprayed with B. bassiana showed greater development of mycosis.More recently, a study performed byCisneros et al (2022) under laboratory conditions identified and evaluated two isolates of B. bassiana through two application forms: direct insect spraying and exposure of psyllid adults on sprayed foliage.…”