Diprion pini L. (Hymenoptera, Symphyta, Diprionidae) population dynamics in the Low Dnieper region

Abstract

Pine sawflies (Hymenoptera, Symphyta, Diprionidae) are the most spread foliage browsing insects of pine forests in Europe, especially monovoltinous European pine sawfly Neodiprion sertifer (Geoffroy, 1785) and common pine sawfly Diprion pini (Linnaeus, 1758), which develops in one or two generations per year depending on weather. The outbreaks of both pine sawflies are the most frequent and intensive in the Steppe zone of Ukraine, especially in the Low Dnieper region, where pine forest (Pinus sylvestris Linnaeus and Pinus pallasiana D. Don) was planted on moving sands in the sixties of the 20th century. This research is aimed at the evaluation of the parameters for D. pini outbreak dynamics in the Low Dnieper region. Outbreak severity, specific foci area and mean score of stand threat by D. pini were evaluated from the regional statistical reports. In the regional scale for 1979–2017, notable outbreaks of D. pini were registered in 1982, 1993, 2002, 2006 and 2017. An interval between maximums was from 4 to 11 years, in average 9 years. The growth of foci area in 1979–1998 as compared to 1999–2017 as well as correlation between pine stand area and annual area of this pest’s foci in different forests was not statistically significant. Graphical analysis of dynamics of D. pini focal area for 2010–2017 was done based on individual threat levels. Our study confirms the fact of three outbreaks for this period in three forest and hunting enterprises (FHE), two outbreaks in one FHE and one outbreak in one FHE. An interval between the outbreaks makes three or six years. The causes of such shortening of interval are discussed.

Forest site conditions and the threat for insect outbreaks in the Scots pine stands of Polissya

“…The foci of mass propagation of foliage browsing insects are formed in favourable ecological conditions, among which the most important is the microclimate, the availability of preferred food, and the absence of natural enemies (Kosunen et al 2017;Hentschel et al 2018;Meshkova et al 2019).…”

Who, Where, When, and How? Challenges for Prediction and Control of Forest Damage

“…Outbreaks of foliage-browsing insects often develop in the same stands at certain time intervals [4,23,24]. At the same time, the severity and duration of outbreaks depend on the stand structure, and the consequences of foliage damage depend, to a large extent, on the initial forest health.…”

Масові розмноження звичайного соснового пильщика (Diprion Pini L.) у лісовому фонді Житомирської області

“…Linnaeus 1758: Hymenoptera; Diprionidae) -один із небагатьох шкідників хвої сосни, який спроможний розвиватися у двох поколіннях на рік (Hentschel et al, 2018;Meshkova et al, 2019). Зазвичай у південних регіонах він має два покоління, а у північних, гірських й у холодні роки -одне (Neuvonen & Viiri, 2017).…”