Large-scale crops are sources of polyphagous pest populations for small farmers at the landscape level: an isotope tracing model

Author(s)

Castro, Erika C. S. ; Camargo, Nicholas F. ; Novaes, Danyelle R. ; Pereira, Marina A. M. ; Nardoto, Gabriela B. ; Togni, Pedro H. B.

• Document type: Journal article
• Source: JOURNAL OF PEST SCIENCE; v. N/A, p. 14-pg., 2023-07-05.

Abstract

Landscape fragmentation caused by agricultural expansion directly influences the spatial distribution of habitats and resources, favoring populations of pest insects such as the polyphagous whitefly Bemisia tabaci. Therefore, pest insects may constantly be dispersing between large- and small-scale crops that vary in quality and size at the landscape level. We aimed to understand how habitat use, dispersal movement and population dynamics of B. tabaci occur between large-scale and small-scale crops. We conducted a field experiment in large-scale soybean farms and small-scale farms cropping tomato plants in Brazil for two years. We collected soybean and tomato plant samples and adult whiteflies on these plants at different times of the phenological cycle of the crops. We determined the carbon and nitrogen stable isotope ratios of the plants and the whiteflies collected on these plants. We also estimated the population densities of whiteflies over time on these crops. We found that whitefly populations behave as metapopulations connected by dispersal. The isotopic ratios of B. tabaci revealed that large-scale soybean crops are source habitats of whitefly populations that, after harvest, disperse and redistribute among small-scale tomato farms causing a cascading effect on population growth on the latter. Therefore, understanding the spatial dynamics and management of pests such as whiteflies requires regional strategies, including large-scale and adjacent small-scale crops. C and N stable isotopes used here were able to track pest populations at the landscape level and, therefore, could be helpful to subsidize area-wide pest management strategies of whiteflies. (AU)

• FAPESP's process: 18/18274-3 - Begomovirus and crinivirus in solanasceous: regional molecular epidemiology and sustainable integrated management alternatives
• Grantee: Jorge Alberto Marques Rezende
• Support Opportunities: Research Projects - Thematic Grants