Szyniszewska, A. M. | Search bioRxiv

bioRxiv2023

Evidence that recent climatic changes have expanded the potential geographic range of the Mediterranean fruit fly

The species distributions migration poleward and into higher altitudes in a warming climate is especially concerning for economically important insect pest species, as their introduction can potentially occur in places previously considered unsuitable for year-round survival. We explore the expansion of the climatically suitable areas for a horticultural pest, the Mediterranean fruit fly (medfly) Ceratitis capitata (Diptera, Tephritidae), with an emphasis on Europe and California. We reviewed and refined a published CLIMEX model for C. capitata, taking into consideration new records in marginal locations, with a particular focus on Europe. To assess the model fit and to aid in interpreting the meaning of the new European distribution records, we used a time series climate dataset to explore the temporal patterns of climate suitability for C. capitata from 1970 to 2019. At selected bellwether sites in Europe, we found statistically significant trends in increasing climate suitability, as well as a substantial northward expansion in the modelled potential range. In California, we also found a significant trend of northward and altitudinal expansion of areas suitable for C. capitata establishment. These results provide further evidence of climate change impacts on species distributions and the need for innovative responses to increased invasion threats.

ecology↗

bioRxiv2019

Cassava planting material movement and grower behaviour in Zambia: implications for disease management

Cassava is an important food crop for most small-holder growers across sub-Saharan Africa, where production is largely limited by the presence of two viral diseases: cassava mosaic disease (CMD) and cassava brown streak disease (CBSD), both propagated by a vector whitefly and via human-mediated movement of infected cassava stems. Despite its importance, there is limited knowledge of growers behaviour related to planting material movement, as well as growers perception and knowledge of cassava diseases, which have major implications for disease spread and control. This study was conducted to address this knowledge gap by surveying small-holder growers in Zambia. A total of 96 subsistence cassava growers across five provinces were surveyed between 2015 and 2017. Most growers interviewed used planting materials from their own fields (94%) or those of nearby (<10 km) family and friends, although some large transactions with markets, middlemen, and NGOs occurred over longer distances. At the same time, information related to cassava diseases and uninfected planting material only reached 48% of growers, where those with access to information were more concerned about the disease. These data provide a basis for future planning of cassava clean seed systems to control virus diseases, emphasising the critical role of grower knowledge, and consequently education, in success of these systems. In particular, we highlight the importance of extension workers in this education process, as well as farmers groups and the media.

epidemiology↗