scholarly journals Evaluation of the Physiological Host Range for the Parasitoid Ooencyrtus mirus, a Potential Biocontrol Agent of Bagrada hilaris

Insects ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 432 ◽  
Author(s):  
Nancy Power ◽  
Fatemeh Ganjisaffar ◽  
Thomas M. Perring

The thelytokous egg parasitoid Ooencyrtus mirus Triapitsyn and Power (Hymenoptera: Encyrtidae) was recovered from brassica plant debris in Pakistan in an effort to find a biological control agent of the invasive bug Bagrada hilaris (Burmeister) (Heteroptera: Pentatomidae) in North America. As the first step in determining the overall host range of this parasitoid, adult females were exposed to the eggs of eight alternate pentatomid host species, two non-pentatomid heteropterans, and two lepidopterans, in choice and no-choice tests. Although O. mirus was more successful on B. hilaris than the other species in terms of the number of the eggs laid, the number of emerged progeny, and the developmental time of the progeny, it was able to reproduce on all of the alternate hosts except for one of the lepidopterans, whose eggs appeared too small for this parasitoid. The results show O. mirus to be a generalist parasitoid species with a preference for B. hilaris. The results also indicate that there is a linear relationship between the mean body length of O. mirus females and the mean host egg weight with an adjusted R 2 of 0.90. The implications of this study on the release of O. mirus for the control of B. hilaris are discussed.

2021 ◽  
Author(s):  
Lucrezia Giovannini ◽  
Giuseppino Sabbatini-Peverieri ◽  
Leonardo Marianelli ◽  
Gabriele Rondoni ◽  
Eric Conti ◽  
...  

Abstract The invasive stink bug Halyomorpha halys is a severe agricultural pest of worldwide importance, and chemical insecticides are largely sprayed for the control of its populations. Negative impacts and several failures in chemical pest management led to consider classical biological control as one of the most promising methods in a long-term perspective. The Asian egg parasitoid Trissolcus japonicus is the main candidate biocontrol agent of H. halys, but more recently a second Asian egg parasitoid, Trissolcus mitsukurii, is getting attention after adventive populations were found on H. halys egg masses in Europe. Before recommending the use of T. mitsukurii for biological control of H. halys, a risk analysis is necessary and therefore here we present the first study on the fundamental physiological host range of this parasitoid in Europe. Tests conducted with T. mitsukurii on different hemipterans, using three different experimental designs, revealed a broad physiological host range, comparable with the host range displayed by T. japonicus under similar laboratory conditions. Specifically, in addition to its coevolved host H. halys, T. mitsukurii successfully parasitized the majority of tested pentatomid species and one scutellerid, although with highly variable emergence rates. Host egg sizes positively affected parasitoid size and female egg load. Further studies, testing more complex systems that involve olfactory cues from host and host plants, will simulate different aspects of the parasitoid host location behavior under field conditions, allowing in-depth evaluation of the possible risks associated with the use of T. mitsukurii as a biocontrol agent of H. halys.


Author(s):  
Lucrezia Giovannini ◽  
Giuseppino Sabbatini-Peverieri ◽  
Leonardo Marianelli ◽  
Gabriele Rondoni ◽  
Eric Conti ◽  
...  

Insects ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 471
Author(s):  
Angelica M. Reddy ◽  
Paul D. Pratt ◽  
Brenda J. Grewell ◽  
Nathan E. Harms ◽  
Ximena Cibils-Stewart ◽  
...  

Exotic water primroses (Ludwigia spp.) are aggressive invaders in aquatic ecosystems worldwide. To date, management of exotic Ludwigia spp. has been limited to physical and chemical control methods. Biological control provides an alternative approach for the management of invasive Ludwigia spp. but little is known regarding the natural enemies of these exotic plants. Herein the biology and host range of Lysathia flavipes (Boheman), a herbivorous beetle associated with Ludwigia spp. in Argentina and Uruguay, was studied to determine its suitability as a biocontrol agent for multiple closely related target weeds in the USA. The beetle matures from egg to adult in 19.9 ± 1.4 days at 25 °C; females lived 86.3 ± 35.6 days and laid 1510.6 ± 543.4 eggs over their lifespans. No-choice development and oviposition tests were conducted using four Ludwigia species and seven native plant species. Lysathia flavipes showed little discrimination between plant species: larvae aggressively fed and completed development, and the resulting females (F1 generation) oviposited viable eggs on most plant species regardless of origin. These results indicate that L. flavipes is not sufficiently host-specific for further consideration as a biocontrol agent of exotic Ludwigia spp. in the USA and further testing is not warranted.


Insects ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 46
Author(s):  
João Frederico Alves ◽  
Sara Mendes ◽  
António Alves da Silva ◽  
José Paulo Sousa ◽  
Daniel Paredes

Olive growing has been intensified through the simplification of agricultural landscapes. In order to rethink the environmental drawbacks of these practices, conservation biological control techniques have been examined. In this work, Prays oleae and its natural enemy Chrysoperla carnea were monitored to account for the effects of the amount and diversity of different land-uses. We found that C. carnea showed an attraction to areas with high abundances of P. oleae but this predator did not display any affection by the different land-uses. Inversely, P. oleae abundance was lower in diverse landscapes and higher in simplified ones. Importantly, higher abundances of C. carnea were related to lower infestation levels of P. oleae in the late part of the season. These results corroborate the attraction of C. carnea to the olive moth, highlighting the potential of C. carnea as a biological control agent of this pest, assert that the promotion of land-use diversity can reduce P. oleae and confirm that landscapes dominated by olive groves can promote this pest. The present study aims at contributing to the discussion about the management of agricultural ecosystems by providing farmers with sustainable alternatives that do not have harmful effects on the environment and public health.


2016 ◽  
Vol 45 (4) ◽  
pp. 897-908 ◽  
Author(s):  
Yanzhuo Zhang ◽  
James L. Hanula ◽  
Scott Horn ◽  
Cera Jones ◽  
S. Kristine Braman ◽  
...  

1990 ◽  
Vol 4 (3) ◽  
pp. 465-470 ◽  
Author(s):  
Gregory J. Weidemann ◽  
David O. Tebeest

The determination of host range is an important component in developing a plant pathogen for use as a bioherbicide. The safety of non-target economic and wild plants must be assured before experimental release and commercial use. In contrast to other methods of weed control, the genetic variability and genetic stability of both the weed and the biological control agent must be considered. Schemes to determine host range generally assume a close phylogenetic relationship between the weed host and its co-evolved pathogens. Therefore, testing generally is based on inoculation of genetically related plant species and progresses to more distantly related species until the host range is circumscribed. Several potential weaknesses in these schemes will be illustrated with examples using specific biological control agents. Future tests must place greater emphasis on testing taxa representing the full range of genetic diversity within the biogeographic area of intended use.


2004 ◽  
Vol 31 (6) ◽  
pp. 651
Author(s):  
G. Story ◽  
J. Scanlan ◽  
R. Palmer ◽  
D. Berman

Rabbit haemorrhagic disease virus (RHDV) escaped from quarantine facilities on Wardang Island in September 1995 and spread through South Australia to Queensland by December 1995. To determine the impact of this biological control agent on wild rabbit populations in Queensland, shot sample and spotlight count data were collected at six sites. RHDV spread across Queensland from the south-west to the east at a rate of at least 91 km month–1 between October 1995 and October 1996. The initial impact on rabbit density appeared highly variable, with an increase of 81% (255 ± 79 (s.e.) to 385 ± 73 rabbits km–2) at one site and a decrease of 83% (129 ± 27 to 22 ± 18 rabbits km–2) at another during the first outbreak. However, after 30 months of RHDV activity, counts were at least 90% below counts conducted before RHDV arrived. Using a population model to account for environmental conditions, the mean suppression of rabbit density caused by rabbit haemorrhagic disease (RHD) was estimated to be 74% (ranging from 43% to 94% between sites). No outbreaks were observed when the density of susceptible rabbits was lower than 12 km–2. Where rabbit density remains low for long periods RHDV may not persist. This is perhaps most likely to occur in the isolated populations towards the northern edge of the range of rabbits in Australia. RHDV may have to be reintroduced into these populations. Further south in areas more suitable for rabbits, RHDV is more likely to persist, resulting in a high density of immune rabbits. In such areas conventional control techniques may be more important to enhance the influence of RHD.


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