Plant Protect. Sci., X:X | DOI: 10.17221/150/2024-PPS

Using thermal time to predict the timing of flight activity in Noctuidae (Lepidoptera) species: Calculation and verification of forecast methodsOriginal Paper

Alois Honěk ORCID...¹, Zdenka Martinková ORCID...¹, Ivo Novák², Terezia Jauschová³, Lenka Sarvašová³, Miroslav Saniga ORCID...³, Milada Holecová ORCID...⁴, Ján Kulfan³, Peter Zach³

¹ Czech Agrifood Research Center, Prague, Czech Republic

² Crop Research Institute, Roztoky, Czech Republic

³ Institute of Forest Ecology, Slovak Academy of Sciences, Zvolen, Slovak Republic

⁴ Department of Zoology, Faculty of Natural Sciences, Comenius University, Bratislava, Slovak Republic

From 1967 to 1995, the flight activity of 25 monovoltine species of moths (Noctuidae, Lepidoptera) was monitored via a light trap located in Prague (50.09 N, 14.30 E). For each species, the day when half of the individuals were caught (peak of flight activity, PFA) was specified each year. This study addresses a method of predicting the calendar date of the PFA via thermal time. We determined a base temperature of +6 °C, at which the differences between the predicted and actual dates of the PFA were minimal. For each species and each year, the sum of the degree days exceeding the base temperature from January 1 to the date of the PFA (SumT) was determined, and the average SumT throughout the study was calculated. Each year, the predicted date of the PFA is the date when the average SumT was achieved. Sixty-five percent of the predicted PFA dates fell within ±5 days of the actual date of the PFA. Shifts in the magnitude and direction of the difference between the actual and predicted PFAs affecting concurrently all species were caused by the thermal conditions of the year.

Keywords: base temperature; peak flight activity; prediction; thermal time

Received: August 27, 2024; Revised: April 29, 2025; Accepted: April 29, 2025; Prepublished online: September 9, 2025