Effect of Agrobacterium tumefaciens on papaya whitefly Trialeurodes variabilis populations infesting papaya Carica papaya

Crown gall disease, caused by Agrobacterium tumefaciens, is a tumor-inducing bacterial infection that alters host plant physiology. While this pathogen is extensively used in plant biotechnology, its role in shaping interactions with herbivorous insects remains poorly understood. In this study, we examined the effects of A. tumefaciens infection on the population dynamics of the papaya whitefly, Trialeurodes variabilis, and on the growth of papaya (Carica papaya) plants. Two greenhouse trials were conducted using healthy plants and plants in the Agrobacterium treatment. In the first trial, densities of whitefly adults were significantly higher in the Agrobacterium treatment. Similarly, in the second trial, densities of whitefly eggs and nymphs were significantly higher in the Agrobacterium treatment. Additionally, plants in the Agrobacterium treatment in the second trial exhibited reductions in plant height, canopy width, stem diameter, and SPAD index. Despite these changes, A. tumefaciens-infected plants remained suitable for supporting whitefly development. These results suggest that A. tumefaciens infection may promote whitefly population growth, highlighting how plant pathogens may influence plant-herbivore interactions. This study offers new insights into how plant-microbe interactions can influence herbivore populations and overall plant health.