Cold tolerance characteristics of Korean population of potato tuber moth, Phthorimaea operculella (Zeller), (Lepidoptera: Gelechiidae)

Abstract

Potato tuber moth (PTM), Phthorimaea operculella (Zeller), (Lepidoptera: Gelechiidae) is an invasive insect pest damaging solanaceous crops. We measured the supercooling point (SCP) and survival at low temperature of different development stages to determine which would be capable of overwintering in the Korean climate and adapting to low temperatures. The SCP ranges from −23.8°C of the egg to −16.8 of fourth instar larvae (L4). After short periods of low temperature acclimation in L3 (third instar larva), L4 and prepupae, only the prepupal stage showed a significant lowered SCP from −20.78 to −22.37°C. When exposed to different subzero temperature for two hours the egg turned out to be the most cold tolerant stage showing LT50 of −21.7°C followed by the pupal stage with −15.89°C. One hundred percent mortality was observed when the larvae or adults were exposed to temperatures below −15.1°C even for a period as short as 2 h. The results suggest that PTM pupae and egg would be the main overwintering stage in Korea where winter temperature does not drop below −15°C.

Suitability of tomato leaves for larval development of Potato Tuber Moth, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae)

“…Gilboa and Podoler (1994) also indicated that the peak population of the PTM in tomato fields was highly correlated with the damage on fruits and foliage and also the damage to tomato escalated after potato was harvested. Therefore presence of PTM on both tomato and potato field could be a source for the pests and could cause outbreak when the weather condition is favorable because the tomato plantation in plastic houses just coincides with the harvesting of potato in Korean conditions (Aryal 2018). We therefore conclude that there is a likely risk of PTM to attack tomato plants and cause economic losses to tomato growers.…”

“…Kroschel et al (2016) clearly indicated that the distribution and generation of this pest in present climate change scenarios has been increasing, and to avoid such risk different integrated management options should be adopted, one of which should be the resistance mechanism to prevent insect from feeding on crops. Recently PTM flight activity has been reported, not only on potato fields, but also in the area of tomato fields (Aryal 2018). Gilboa and Podoler (1994) also indicated that the peak population of the PTM in tomato fields was highly correlated with the damage on fruits and foliage and also the damage to tomato escalated after potato was harvested.…”

“…(Briese ; Cisneros & Gregory ). In Korea, the PTM was first noticed during 1963–1964 in Jeju (having arrived there possibly from nearby Japan), and subsequently found to be initially restricted to the southern parts of South Korea (Aryal & Jung ; Choe & Park ). Recent surveys, however, showed that the PTM had expanded its distribution further to the north (Kwon et al ).…”

“…The PTM can overwinter in extreme weather condition and appear in the late spring (Aryal & Jung ) and can survive in lower temperatures (Aryal & Jung 1018). Due to vulnerable climatic condition of the Korean peninsula and being warmer gradually due to climate change and cold adaptive characteristics of PTM, it may switch to its host to tomato because it is congeneric with the potato.…”

The Journey of the Potato Tuberworm Around the World

“…Kfir [168] studied the fertility of C. koehleri compared to Apanteles subandinus L. under the effect of humidity in South Africa, concluding that low humidity is detrimental for the survivorship of this species. Choi et al [169] and Aryal and Jung [170] reported Diadegma fenestrale L. found for the first time in Korea and accounted for 20-30% parasitism. In Sardinia, Diadegma turcator Aubert, and Bracon nigricans L., B. properhebetor L., and Apanteles spp.…”