The Probing Behavior Component of Disease Transmission in Insect-Transmitted Bacterial Plant Pathogens

Abstract

Insects can be effective vectors of plant diseases and this may result in billions of dollars in lost agricultural productivity. New, emerging or introduced diseases will continue to cause extensive damage in afflicted areas. Understanding how the vector acquires the pathogen and inoculates new hosts is critical in developing effective management strategies. Management may be an insecticide applied to kill the vector or a host plant resistance mechanism to make the host plant less suitable for the vector. In either case, the tactic must act before the insect performs the key behavior(s) resulting in either acquisition or transmission. This requires knowledge of the timing of behaviors the insect uses to probe the plant and commence ingestion. These behaviors are visualized using electropenetrography (EPG), wherein the plant and insect become part of an electrical circuit. With the tools to define specific steps in the probing process, we can understand the timing of acquisition and inoculation. With that understanding comes the potential for more relevant testing of management strategies, through insecticides or host plant resistance. The primary example will be Candidatus Liberibacter asiaticus transmitted by Diaphorina citri Kuwayama in the citrus agroecosystem, with additional examples used as appropriate.

Assessment of Variation in Feeding Behavior by Color Morph in the Asian citrus Psyllid (Diaphorina citri)

“…Although we did not explicitly test color morph influence on CLas transmission, the feeding behavior data presented here can be extrapolated to consider color morph effects based on known associations between vector feeding and the acquisition and inoculation of phloem restricted pathogens (Ebert 2019: Carmo-Souza et al 2020. Since CLas inoculation is related to the frequency and duration of phloem salivation events (Wu et al 2016;Carmo-Sousa et al 2020), the lack of differences detected for the E1 parameter support the hypothesis of no correlation between color morphology and CLas inoculation.…”

Unravelling the Pathogenesis and Molecular Interactions of Liberibacter Phytopathogens with Their Psyllid Vectors

“…CLas-infected D. citri nymphs are also reported to develop faster than uninfected ones [72,73]. On the contrary, females are reported to invest more in immune response and survival to maintain long term reproductive viability, which causes increased oviposition for liberibacter-infected psyllids, however with reduced nymphal development and adult survivability [73,74].…”

Effect of tree height and spraying methods on Diaphorina citri kuwayama endosymbionts in the context of Huanglongbing disease management in citrus orchards

“…[22][23][24][25][26] These endosymbionts not only occupy the psyllid's body cavity but also interact with the HLB pathogen and the host plant, creating a complex network of associations. [27][28][29][30][31][32][33][34][35] These differential responses of psyllids from varying tree ages emphasize the intricate interplay between host-symbiont interactions and the physiological attributes of psyllids at different developmental stages. The underlying mechanisms driving this discrepancy warrant further investigation, as they may hold critical implications for our understanding of vector biology and HLB transmission dynamics.…”