Implementing mass rearing of trissolcus japonicus (Hymenoptera: Scelionidae) on cold-stored host eggs

Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), a pest of Asian origin, has been causing severe damage to Italian agriculture. The application of classical biological control by the release of Trissolcus japonicus (Ashmead) (Hymenoptera: Scelionidae), an exotic egg parasitoid, appears to be one promising solution. In Italy, releases of T. japonicus in the field were authorized in 2020. In this study, some parameters that could influence the rearing of T. japonicus in insectaries were investigated. A significantly higher production of progeny was observed on host eggs stored at 6◦C (86.5%) compared to −24◦C (48.8%) for up to two months prior to exposure to parasitism. There were no significant differences in progeny production from single females in a vial provided with only one egg mass (83.2%) or 10 females inside a cage with 6 egg masses (83.9%). The exposure of parasitoids to refrigerated (6◦C) egg masses of H. halys for 72 h led to a significantly higher production of progeny (62.1%) compared to shorter exposures for 48 (44.0%) or 24 h (37.1%). A decline in production of progeny by the same female was detected between the first (62.1%) and the second parasitization (41.3%). Adult parasitoids stored at 16◦C for up to 90 days had an 87.1% survival rate, but a significant decrease in progeny production was detected. These parameters could be adjusted when rearing T. japonicus for specific aims such as the production of individuals for field release or colony maintenance

Invasion biology of spotted wing Drosophila (Drosophila suzukii): a global perspective and future priorities

The Asian vinegar fly Drosophila suzukii (spotted wing Drosophila [SWD]) has emerged as a major invasive insect pest of small and stone fruits in both the Americas and Europe since the late 2000s. While research efforts have rapidly progressed in Asia, North America, and Europe over the past 5 years, important new insights may be gained in comparing and contrasting findings across the regions affected by SWD. In this review, we explore common themes in the invasion biology of SWD by examining (1) its biology and current pest status in endemic and recently invaded regions; (2) current efforts and future research needs for the development of predictive models for its geographic expansion; and (3) prospects for both natural and classical (=importation) biological control of SWD in invaded habitats, with emphasis on the role of hymenopteran parasitoids. We conclude that particularly fruitful areas of research should include fundamental studies of its overwintering, host-use, and dispersal capabilities; as well as applied studies of alternative, cost-effective management techniques to complement insecticide use within the integrated pest management framework. Finally, we emphasize that outreach efforts are critical to effective SWD management by highlighting successful strategies and insights gained from various geographic regions.This is the publisher’s final pdf. The published article is copyrighted by Springer and can be found at: http://link.springer.com/journal/10340Keywords: Integrated pest management, Biological control, Drosophila, Frugivore, Invasion biolog

Selectivity of Whitefly Traps in Cotton for \u3ci\u3eEretmocerus eremicus\u3c/i\u3e (Hymenoptera: Aphelinidae), a Native Parasitoid of \u3ci\u3eBemisia argentifolii\u3c/i\u3e (Homoptera: Aleyrodidae)

Yellow sticky traps are widely used for monitoring and management of whiteflies and certain other pests and have also been used to monitor their natural enemy activity. A new, nonsticky whitefly trap (CC trap), standard yellow sticky cards, and clear colorless sticky cards were evaluated in cotton (Gossypium hirsutum L.) to compare their attractiveness to Eretmocerus eremicus Rose and Zolnerowich, an aphelinid parasitoid of Bemisia argentifolii Bellows & Perring [=Bemisia tabaci (Gennadius) B-strain 1 that is indigenous to southwestern U.S. deserts. The CC traps caught an average of 264 adult whiteflies during 24-h test periods compared with 523 adult whiteflies on yellow sticky traps. The colorless sticky cards trapped only 37 whiteflies per card during the same period. The CC traps caught an average of 0.4 adult E. eremicus over a 24-h period compared with 26.6 adult E. eremicus trapped by yellow sticky cards. Colorless plastic sticky cards trapped an average of 1.1 parasitoids per card, demonstrating that E. eremicus was strongly attracted to the yellow sticky cards. Thirty-nine percent of E. eremicus trapped on yellow sticky cards and 42% trapped on colorless sticky cards were female. CC traps caught the lowest numbers of other arthropods. On average, \u3c1 individual of any other species was captured per CC trap in each 24-h period. Yellow sticky traps caught the greatest number of other arthropods; these included thrips, flies, cotton leafperforator (Buccalatrix thurberiella Busck) moths, small beetles, and other parasitic wasps. Clear sticky traps caught a similar mixture of species but in lower numbers. These results demonstrate that CC traps are highly selective for whitefly, while preserving parasitoid populations. CC traps may be especially useful in greenhouses where yellow sticky traps are frequently used in conjunction with releases of parasitoids

Correction: Tritrophic analysis of the prospective biological control of brown marmorated stink bug, Halyomorpha halys, under extant weather and climate change (Journal of Pest Science, (2023), 10.1007/s10340-023-01610-y)

Following publication of the original article [1], an error was identified under “Discussion” section in the first paragraph of “A regional perspective”, the following text appears: 0.294 ETj, R2 = 0.94) suggests that given the same search rate and A. sinicus preference, EEE could attack ~ threefold more BMSB eggs than T. mitsukurii. This result reflects “EEE” should be replaced with “T. japonicus” The original article [1] has been corrected

Tritrophic analysis of the prospective biological control of brown marmorated stink bug, Halyomorpha halys, under extant weather and climate change

The highly destructive Asian brown marmorated stink bug (Halyomorpha halys, BMSB) invaded Europe, Caucasus region, and North and South America. Efforts to control it are ongoing in the Palearctic European-Mediterranean Basin and North America by introducing and redistributing two Asian stenophagous scelionid egg parasitoids (Trissolcus japonicus and T. mitsukurii) that are attacked by an adventive oligophagous pteromalid Asian hyperparasitoid (Acroclisoides sinicus). Large BMSB nymphs and adults may be parasitized by new associations of oligophagous tachinid flies and immature stages by egg parasitoids and predators. The terms stenophagous and oligophagous are commonly used to define narrow and wider ranges, respectively, of food eaten, but here they refer to the range of hosts attacked by adult female parasitoids. A holistic weather-driven physiologically based demographic model (PBDM) of the tritrophic interactions was developed to evaluate prospectively the impact of natural enemies on the biological control of BMSB under current and climate change weather. Our study focuses on the European-Mediterranean region, with the results for the USA, Mexico, and Central America reported as supplementary information. The PBDM analysis suggests that biotypes of the egg parasitoids T. japonicus and T. mitsukurii with high search capacity could suppress BMSB regionally, but the requisite levels of parasitism by these parasitoids for economic control are not observed in their native range nor in invaded areas. The model suggests that the action of T. japonicus is greater than that of T. mitsukurii, but that joint interactions of the two egg parasitoids would provide higher mortality of BMSB. Field data and model results suggest that the egg hyperparasitoid A. sinicus has a modest negative impact on the suppression of BMSB. Moreover, tachinid parasitoids of adults could have an important supplemental role in suppressing BMSB densities. Analysis suggests that new biotypes of egg parasitoids and species of tachinid parasitoids of large nymphs and adults be sought

Exploration for olive fruit fly parasitoids across Africa reveals regional distributions and dominance of closely associated parasitoids.

The olive fruit fly, Bactrocera oleae, has been a key pest of olives in Europe and North America. We conducted the largest exploration for parasitoids associated with the fly across Sub-Saharan Africa (Kenya, Namibia, and South Africa) including some of the fly's adjoining regions (Canary Islands, Morocco, Réunion Island and Tunisia). From Sub-Saharan regions, four braconids were collected: Bracon celer, Psytallia humilis, P. lounsburyi, and Utetes africanus. Results showed that their regional dominance was related to climate niches, with P. humilis dominant in hot semi-arid areas of Namibia, P. lounsburyi dominant in more tropical areas of Kenya, and U. africanus prevalent in Mediterranean climates of South Africa. Psytallia concolor was found in the Canary Islands, Morocco and Tunisian, and the Afrotropical braconid Diachasmimorpha sp. near fullawayi on Réunion Island. Furthermore, we monitored the seasonal dynamics of the fly and parasitoids in Cape Province of South Africa. Results showed that fruit maturity, seasonal variations in climates and interspecific interactions shape the local parasitoid diversity that contribute to the low fly populations. The results are discussed with regard to ecological adaptations of closely associated parasitoids, and how their adaptations impact biocontrol

Phylogeography of the Wheat Stem Sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae): Implications for Pest Management.

The wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), is a key pest of wheat in the northern Great Plains of North America, and damage resulting from this species has recently expanded southward. Current pest management practices are inadequate and uncertainty regarding geographic origin, as well as limited data on population structure and dynamics across North America impede progress towards more informed management. We examined the genetic divergence between samples collected in North America and northeastern Asia, the assumed native range of C. cinctus using two mitochondrial regions (COI and 16S). Subsequently, we characterized the structure of genetic diversity in the main wheat producing areas in North America using a combination of mtDNA marker and microsatellites in samples collected both in wheat fields and in grasses in wildlands. The strong genetic divergence observed between North American samples and Asian congeners, in particular the synonimized C. hyalinatus, did not support the hypothesis of a recent American colonization by C. cinctus. Furthermore, the relatively high genetic diversity both with mtDNA and microsatellite markers offered additional evidence in favor of the native American origin of this pest. The genetic diversity of North American populations is structured into three genetic clusters and these are highly correlated with geography. Regarding the recent southern outbreaks in North America, the results tend to exclude the hypothesis of recent movement of damaging wheat stem sawfly populations from the northern area. The shift in host plant use by local populations appears to be the most likely scenario. Finally, the significance of these findings is discussed in the context of pest management