Parasitoid complex of the bird cherry ermine moth Yponomeuta evonymellus in Korea

Abstract

The parasitoid complex of Yponomeuta evonymellus L. (Lepidoptera: Yponomeutidae), the bird cherry ermine moth (BCEM), was sought in South Korea with the goal of identifying its potential biological controls. Thirteen primary and two secondary parasitoids were found. Diadegma armillatum (Grav.), Herpestomus brunnicornis Grav. (Icheumonidae), and Zenillia dolosa (Meigen) (Tachinidae) were the most important parasitoids causing 3.5%, 7.1%, and 7.7% of the combined parasitism of the host larvae and pupae, respectively. The composition of parasitoid species was more diverse in larvae than in pupae; 10 species were reared from larvae, compared to six from pupae. The parasitoid complex contributed to the relatively low mortality levels of Yponomeuta evonymellus with the combined total rate of parasitism of 29.6% for the host larvae and pupae. This level is below that found in some European populations (50%) and is not greater than the larval rate of parasitism (31%) found in the congeneric apple ermine moth in Korea. This low rate of parasitism is partly attributed to the parasitism by Ageniaspis fuscicollis (1%) detected in Yponomeuta evonymellus, which is similar to that detected in Yponomeuta evonymellus in European reports. This is the first report of the parasitoid complex attacking the BCEM in Korea.

Changing Host Plants Causes Structural Differences in the Parasitoid Complex of the Monophagous Moth Yponomeuta evonymella, but Does Not Improve Survival Rate

“…Anomalon anxium ) is a polyphagous larval/pupal parasitoid. In the past, it did not have a meaningful influence on the population of Y. evonymella in Poland [51] and induced parasitism rates of less than 0.5% in Asian populations [29]. In the current study, mean parasitism by this parasitoid was visibly greatest in larvae reared on P. serotina (more than 15-fold higher than in the P. padus variant).…”

“…The collapse of a mass outbreak is typically caused mainly by parasitoids [50]. The transitional periods between outbreaks are characterised by approximately 50% parasitisation of the population in Central Europe [21] and approximately 30% in East Asian populations [29]. The results of our research show that a Polish population of Y. evonymella was in a transitional period between outbreaks, as indicated by the observed total larval parasitism (ca.…”

“…2.3%) in larvae feeding on P. padus alone and those feeding on P. padus / P. serotina , but it was absent in larvae feeding on P. serotina alone. In a study [29] conducted in Korea, H. brunnicornis caused relatively high parasitism (6.8%) of pupal Y. evonymella , but it only caused 0.3% of parasitism in larvae.…”

“…Populations of Y. evonymella are substantially reduced by natural enemies, such as bird predators and parasitoids. Historically in Europe, 34 parasitoids and 15 predators of Y. evonymella have been reported [29]. A recently updated checklist of the diversity of natural enemies of European species of the genus Yponomeuta provides information concerning 60 species [30].…”

Pupal Parasitoids ofYponomeuta malinellus(Lepidoptera: Yponomeutidae) in Northeast Asia

“…Nemorilla floralis (Fallen) has been recorded as a larval parasitoid of Cacoecia piceana Linne (Tortricidae), Cnaphalocrocis medinalis Guenee (Pyralidae), Euproctis flava Bremer (Lymantriidae), and Palpita nigropunctalis Bremer (Pyralidae) (Yasumatsu & Watanabe 1965). It was reported to parasitize Yponomeuta padellus (L.) (Friese 1963), and is a larval-pupal parasitoid of Y. evonymelus (Lee & Pemberton 2009).…”