Biology, parasitoid complex and potential distribution of saxaul's dominant defoliators, Teia dubia (Lepidoptera: Lymantriidae)

Natural enemies that impact pest populations must be understood in order to build integrated pest control strategies and to understand the most important aspects affecting pest dynamics. Haloxylon ammodendron (C. A. Mey.) Bunge is an important perennial plant species extensively used in sand stabilization and wind prevention in arid areas. This study aimed to determine the main defoliators that damage H. ammodendron and the parasitoid complex associated with them. Twelve species of defoliators were found in Northern Xinjiang, and Teia dubia (Tauscher) (Lepidoptera: Lymantriidae), Scrobipalpa sp. (Lepidoptera: Gelechiidae), and Eucharia festiva Hüfnagel (Lepidoptera: Arctiidae) were the dominant pests. T. dubia is the predominant defoliator with three generations a year. Northwest China, Central Asia, and the Mediterranean region are potentially suitable habitats for T. dubia in the world, while Xinjiang is the primary distribution area in China. Parasitoids belonging to seven species and four families were reared from the larvae of T. dubia, they were all endoparasitoids and koinobiont. Cotesia sp. (Hymenoptera: Braconidae) is the dominant parasitoid and prefer to parasitic in the 3rd–5th instar larvae. The present study provides the basis for understanding the species composition and natural enemies of lepidopteran defoliators. It will be an effective tool for the integrated pest management programs of H. ammodendron forest.

Naturalized Dolichogenidea gelechiidivoris Marsh (Hymenoptera: Braconidae) complement the resident parasitoid complex of Tuta absoluta (Meyrick) (Lepidopera:Gelechiidae) in Spain

Our study aimed to assess the contribution of natural parasitism due to Necremnus tutae Ribes & Bernardo (Hymenoptera: Eulophidae) to the biological control of Tuta absoluta (Meyrick) (Lepidopera:Gelechiidae) in commercial plots where an IPM program based on the use of predatory mirid bugs was implemented. During the samplings, the presence of another parasitoid was detected and, therefore, a second part of our study intended to identify this species and to evaluate the importance of its natural populations in the biological control of the pest. Leaflets with T. absoluta galleries were collected during 2017-2020 from commercial tomato plots in the horticultural production area of Catalonia (Northeast Spain), including greenhouses, open fields, and roof covered tunnels that lack side walls. In the laboratory, T. absoluta larvae were classified as ectoparasitized, alive, or dead. Reared parasitoids from ectoparasitized larvae were mostly morphologically identified as Necremnus sp. with parasitism rates that peaked in summer months with values between 9 and 15%. Some of these ectoparasitized larvae also yielded another parasitoid identified as Dolichogenidea gelechiidivoris Marsh (Hymenoptera: Braconidae) by both morphological and molecular-DNA barcoding methods. In 2020, parasitism rates due to D. gelechiidivoris that increased with season up to 22%. Our work reports for the first time in Europe the presence of the neotropical species D. gelechiidivoris adding this biocontrol agent to the resident parasitoid complex of T. absoluta in Spain.

Egg parasitoid complex of the pine processionary moth (Thaumetopoea pityocampa) on the Thasos Island, Greece

The egg parasitoid complex of the pine processionary moth (Thaumetopoea pityocampa) was surveyed for the first time on the Thasos Island, Greece. A total of 96 egg batches containing 20391 eggs were collected between 06 and 10 of September, 2017 from Aleppo pines (Pinus halepensis) at four sites (Skidia, Thimonia, Alyki and Panagia). Four primary parasitoids were identified (Ooencyrtus pityocampae, Baryscapus servadeii, Anastatus bifasciatus and Trichogramma sp.), as well as the hyperparasitoid B. transversalis. Among the parasitoids groups, O. pityocampae was the most common, followed by B. servadeii, whilst the number of other species was low. The highest survival rate was reported for three species: O. pityocampae, B. servadeii and A. bifasciatus, while the highest was the mortality in Trichogramma sp. All emerged adults of O. pityocampae and B. servadeii were female specimens and in A. bifasciatus – males. The number of females of B. transversalis was three times higher than the one of males. Ooencyrtus pityocampae and B. servadeii were the most important parasitoids of T. pityocampa, destroying respectively 27.1% and 9.9% of the host eggs.

Parasitoid Complex of Fall Armyworm, Spodoptera frugiperda, in Ghana and Benin

The fall armyworm, Spodoptera frugiperda, a moth originating from the American continent, has recently invaded most African countries, where it is seriously threatening food security as a pest of cereals. The current management methods rely heavily on the use of synthetic insecticides but there is a need for more sustainable control methods, including biological control. Surveys were conducted in two West African countries, Ghana and Benin, to determine the native parasitoid complex and assess parasitism rates of S. frugiperda. Samples of S. frugiperda eggs and larvae were collected in maize fields located in 56 and 90 localities of Ghana and Benin, respectively, from July 2018 to July 2019. Ten species were found parasitizing the pest, including two egg parasitoids, one egg–larval, five larval and two larval–pupal parasitoids. The two most abundant parasitoids in both countries were two Braconidae: the egg-larval parasitoid Chelonus bifoveolatus and the larval parasitoid Coccygidum luteum. Parasitism rates were determined in three Ghanaian regions and averages varied from 0% to 75% between sites and from 5% to 38% between regions. These data provide an important baseline for the development of various biological control options. The two egg parasitoids, Telenomus remus and Trichogramma sp. can be used in augmentative biological control and investigations should be conducted to assess how cultural practices can enhance the action of the main parasitoids, C. luteum and Ch. bifoveolatus, in the field. Understanding the parasitoid complex of S. frugiperda in Africa is also necessary before any development of classical biological controls involving the introduction of parasitoids from the Americas.

Complexul parazitoid al cinipidului Neuroterus Quercusbaccarum (Hymenoptera, Cynipidae) ce se dezvoltă pe frunze de stejar

The research of parasitoid calcidids associated with the cinopid Neuroterus quercusbaccarum L. (Hymenoptera, Cynipidae) was performed in the forest ridges of the northern and central districts of the Republic of Moldova during the years 2016-2018. In total, more than 1000 gallons were collected, of which eights pecies of entomophagus included in 7 genres and 6 families were obtained under laboratory conditions: Pteromalidae – Mesopolobus tibialis Westw., M. Fasciiventris Westw.; Eupelmidae – Eupelmus fulvipes Förster, Eulophidae – Olynx gallarum L., Tetrastichus sp., Ormyridae – Ormyrus diffinis Fonsc., Eurytomidae – Eudecatoma biguttata Swed.; Torymidae – Torymus flavipes Walker. In the parasitoid complex with a higher percentage of parasites, threes pecies were found: Torymus flavipes Walker (Chalcidoidea, Torymidae), Mesopolobus tibialis Westw., M. Fasciiventris Westw. (Chalcidoidea, Pteromalidae). The lowest percentage of parasites was recorded in Tetrastichus sp. (Chalcidoidea, Eulophidae). Torymus flavipes Walker iscited as a new species for Moldova’s fauna. For the first time there has been infestation of this host with parasitoids: Mesopolobus fasciiventris Westw. (Pteromalidae), Ormyrus diffinis Fonsc. (Ormyridae), Eudecatoma biguttataSwed. (Eurytomidae), Eupelmus fulvipes Förster (Eupelmidae); Tetrastichus sp. (Eulophidae), Torymus flavipes Walker (Torymidae).

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

Recently in Poland, cases of host expansion have frequently been observed in the typically monophagous bird-cherry ermine moth (Yponomeuta evonymella), which has moved from its native host plant, bird cherry (Prunus padus), to a new, widely distributed plant that is invasive in Europe, black cherry (P. serotina). We attempted to verify the reasons behind this host change in the context of the enemy-free space hypothesis by focusing on parasitoids attacking larval Y. evonymella on one of three host plant variants: The primary host, P. padus; initially P. padus and later P. serotina (P. padus/P. serotina); or the new host, P. serotina. This experiment investigated if changing the host plant could be beneficial to Y. evonymella in terms of escaping from harmful parasitoids and improving survival rate. We identified nine species of parasitoids that attack larval Y. evonymella, and we found that the number of parasitoid species showed a downward trend from the primary host plant to the P. padus/P. serotina combination to the new host plant alone. We observed a significant difference among variants in relation to the percentage of cocoons killed by specific parasitoids, but no effects of non-specific parasitoids or other factors. Total mortality did not significantly differ (ca. 37%) among larval rearing variants. Changing the host plant caused differences in the structure of the parasitoid complex of Y. evonymella but did not improve its survival rate. This study does not indicate that the host expansion of Y. evonymella is associated with the enemy-free space hypothesis; we therefore discuss alternative scenarios that may be more likely.