Impact of low temperature and host plant on Tuta absoluta

Alternative host plants are among the key factors influencing the spread of invasive pests because they are utilized as a food source and provide shelter in unfavorable conditions. The South American tomato pinworm (SATP), Tuta absoluta Meyrick (Lepidoptera: Gelechiidae), has a high behavioral and physiological plasticity enabling it to rapidly spread in several countries. Among the multiple strategies used by SATP in the invasion process is the use of alternative host plants including black nightshade (BNS), Solanum nigrum L. (Solanaceae), a perennial plant widely distributed across all habitats worldwide. Besides the life table and behavioral parameters of SATP on tomato, its survival and reproduction in low temperatures on alternative host plants should be assessed to evaluate the likely spread in temperate regions with harsh winters. In our study, comparing solanaceous species through generations, the primary difference was in the mean generation time with SATP reared on BNS, whereby it had a longer development time than larvae and pupae reared on tomato plants. Adults preferred tomato plants even if they had been reared as larvae on BNS. Exposure periods of 7, 14, and 21 days to 4 degrees C indicated that more than 50% of SATP pupae reared on BNS plants survived more than 14 days. The survival of SATP reared on tomato plants exceeded 21 days and after exposure to 4 degrees C, females reared on both plants remained fertile. The life table and behavioral parameters recorded demonstrated a significant potential of BNS to support the development of SATP, also at low temperature. Therefore, even with effective border surveillance and phytosanitation processes in place, invasion through an alternative host is possible and difficult to detect.

Automated summary

The South American tomato pinworm has the potential to develop on alternative host plants, especially in low temperature environments. Long-term exposure to low temperatures affects the survival of the pest, but even at lower temperatures, its survival on tomato plants exceeds that on alternative host plants.