scholarly journals The Lari-Leuco Container: A Novel Collection Arena for Separating Insects Ascending or Descending From a Plant Foliage Sample

Author(s):  
Albert E Mayfield ◽  
Nicholas J Dietschler ◽  
Mark C Whitmore

Abstract Efficient separation of insects from plant material for quantification and collection is an important component of entomological research. This paper reports on a novel, easily replicable container designed to efficiently collect two different biological control agents dispersing from hemlock (Tsuga spp.) foliage infested with the invasive hemlock woolly adelgid (HWA), Adelges tsugae Annand (Hemiptera: Adelgidae). The container utilizes a simplified Berlese-style funnel design to collect Laricobius spp. (Coleoptera: Derodontidae) larvae dropping from the foliage into a removable bottom jar, a central jar to house the foliage sample, and a removable top jar to collect adult silver flies (Leucopis spp., Diptera: Chamaemyiidae) emerging from puparia on the twigs. The efficacy of two designs (with and without a funnel leading to the top collection jar) was evaluated using western hemlock [Tsuga heterophylla (Raf.) Sarg.] foliage naturally colonized with HWA and the two predator genera. All Laricobius larvae were effectively collected in the bottom jar, and the addition of an inverted funnel leading to the top collection jar increased the proportion of Leucopis flies reaching the target jar from 60% to 94%. This ‘Lari-Leuco’ container is presented as a research and motoring tool to benefit the integrated pest management program for HWA in eastern North America and for potential use in simultaneously separating ascending and descending life stages in other insect-plant or predator-prey systems.

2020 ◽  
Vol 49 (4) ◽  
pp. 823-828
Author(s):  
Alex N Neidermeier ◽  
Darrell W Ross ◽  
Nathan P Havill ◽  
Kimberly F Wallin

Abstract Two species of silver fly, Leucopis argenticollis (Zetterstedt) and Leucopis piniperda (Malloch) (Diptera: Chamaemyiidae), from the Pacific Northwest region of North America have been identified as potential biological control agents of hemlock woolly adelgid (Hemiptera: Adelgidae: Adelges tsugae Annand) in eastern North America. The two predators are collectively synchronized with A. tsugae development. To determine whether adult emergence of the two species of silver fly are also synchronized with one another, we collected adult Leucopis which emerged from A. tsugae-infested western hemlock [Pinaceae: Tsuga heterophylla (Raf.) Sarg.] from four sites in the Pacific Northwest over a 29-d period. Specimens were collected twice daily in the laboratory and identified to species using DNA barcoding. The study found that more adult Leucopis were collected in the evening than the morning. Additionally, the daily emergences of adults over the 29-d sampling period exhibited sinusoidal-like fluctuations of peak abundance of each species, lending evidence to a pattern of temporal partitioning. This pattern could have logistical implications for their use as biological control agents in eastern North America, namely the need to release both species for maximum efficacy in decreasing A. tsugae populations.


2016 ◽  
Vol 106 (4) ◽  
pp. 546-550 ◽  
Author(s):  
G.R. Kohler ◽  
K.F. Wallin ◽  
D.W. Ross

AbstractAdelges tsugae infested western hemlock trees were sampled periodically for 1 year at two locations in Oregon and Washington to compare the phenology and abundance of three associated predators (Leucopis argenticollis, Leucopis piniperda, and Laricobius nigrinus) and their host. On each sample date, two 3–10 cm long terminal twigs were collected from each tree and brought to the laboratory to count all life stages of A. tsugae and the three predators. Peak larval abundance of Leucopis spp. and La. nigrinus coincided with the presence of A. tsugae adults and eggs. Leucopis spp. larvae were present for a much longer period of time than were La. nigrinus larvae. Furthermore, Leucopis spp. larvae were present during both the progrediens and sistens egg stages, while La. nigrinus larvae were only present during the progrediens egg stage. Overall, we collected 2.3–3.5 times more Leucopis spp. of all life stages than La. nigrinus. These results support the continued study of Leucopis spp. from the Pacific Northwest as biological control agents for A. tsugae in the Eastern USA.


2006 ◽  
Vol 138 (5) ◽  
pp. 595-601 ◽  
Author(s):  
G.M.G. Zilahi-Balogh ◽  
L.M. Humble ◽  
L.T. Kok ◽  
S.M. Salom

AbstractLaricobius nigrinus Fender, native to western North America, was first released in 2003 for the biological control of the hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), in the eastern United States. Members of the genus Laricobius are known to feed on adelgids, but there is a lack of detailed taxonomic and ecological information on this group of insects. Detailed descriptions and illustrations of various life stages of L. nigrinus are presented in this study, accompanied by notes on its life history to facilitate its recognition.


Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1043
Author(s):  
George T. Tziros ◽  
Anastasios Samaras ◽  
George S. Karaoglanidis

Olive leaf spot (OLS) caused by Fusicladiumoleagineum is mainly controlled using copper fungicides. However, the replacement of copper-based products with eco-friendly alternatives is a priority. The use of plant resistance-inducers (PRIs) or biological control agents (BCAs) could contribute in this direction. In this study we investigated the potential use of three PRIs (laminarin, acibenzolar-S-methyl, harpin) and a BCA (Bacillus amyloliquefaciens FZB24) for the management of OLS. The tested products provided control efficacy higher than 68%. In most cases, dual applications provided higher (p < 0.05) control efficacies compared to that achieved by single applications. The highest control efficacy of 100% was achieved by laminarin. Expression analysis of the selected genes by RT-qPCR revealed different kinetics of induction. In laminarin-treated plants, for most of the tested genes a higher induction rate (p < 0.05) was observed at 3 days post application. Pal, Lox, Cuao and Mpol were the genes with the higher inductions in laminarin-treated and artificially inoculated plants. The results of this study are expected to contribute towards a better understanding of PRIs in olive culture and the optimization of OLS control, while they provide evidence for potential contributions in the reduction of copper accumulation in the environment.


2006 ◽  
Vol 36 (6) ◽  
pp. 1435-1450 ◽  
Author(s):  
Anne K Eschtruth ◽  
Natalie L Cleavitt ◽  
John J Battles ◽  
Richard A Evans ◽  
Timothy J Fahey

Hemlock woolly adelgid (HWA; Adelges tsugae Annand) infestations have resulted in the continuing decline of eastern hemlock (Tsuga canadensis (L.) Carrière) throughout much of the eastern United States. In 1994 and 2003, we quantified the vegetation composition and structure of two hemlock ravines in the Delaware Water Gap National Recreation Area. This is the first study to use pre-adelgid disturbance data, annual monitoring of infestation severity, and annual records of hemlock health to assess forest response to HWA infestation. In 2003, 25% of monitored hemlock trees were either dead or in severe decline. Measures of hemlock decline (crown vigor, transparency, density, and dieback) were correlated with HWA infestation severity and changes in light availability over the study period. Average percent total transmitted radiation more than doubled at these sites from 5.0% in 1994 to 11.7% in 2003. The total percent cover of vascular plants increased from 3.1% in 1994 to 11.3% in 2003. Species richness increased significantly, and more species were gained (53) than lost (19) from both ravine floras over the 9-year study period. Though exotic invasive plants were absent from these ravines in 1994, our 2003 resurvey found invasive plants in 35% of the permanent vegetation plots.


Forests ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 558
Author(s):  
Molly Darr ◽  
Rachel Brooks ◽  
Nathan Havill ◽  
E. Hoebeke ◽  
Scott Salom

The hemlock woolly adelgid (HWA), Adelges tsugae, is an invasive pest of Tsuga spp. in eastern North America. Scymnus coniferarum is a predaceous beetle that was collected from HWA in the western United States. Limited knowledge of this insect in its native habitat led to studies to evaluate its potential for biological control of HWA. Seasonal abundance was sampled at six sites in Tacoma, WA, twice monthly, for one year on different host trees of potential adelgid prey. Tree species included Pseudotsuga menziesii, Pinus contorta, Pinus monticola, and Tsuga heterophylla. Scymnus coniferarum adults were found on all conifer species, except P. menziesii. Each conifer species supported a different adelgid species, suggesting S. coniferarum feeds on multiple adelgid species. More S. coniferarum were found on pine than hemlock. DNA barcoding of S. coniferarum found two distinct clusters that differed by 6% divergence. Beetles in each cluster were co-habiting the same conifer species, and they could not be distinguished morphologically. Further taxonomic studies are needed to understand the significance of DNA barcode sequence divergence. Because S. coniferarum was more frequently associated with pine adelgids than HWA, and because of remaining taxonomic uncertainty, S. coniferarum may not be suitable for HWA biological control.


Insects ◽  
2018 ◽  
Vol 9 (4) ◽  
pp. 172 ◽  
Author(s):  
Aaron Ellison ◽  
David Orwig ◽  
Matthew Fitzpatrick ◽  
Evan Preisser

The nonnative hemlock woolly adelgid is steadily killing eastern hemlock trees in many parts of eastern North America. We summarize impacts of the adelgid on these forest foundation species; review previous models and analyses of adelgid spread dynamics; and examine how previous forecasts of adelgid spread and ecosystem dynamics compare with current conditions. The adelgid has reset successional sequences, homogenized biological diversity at landscape scales, altered hydrological dynamics, and changed forest stands from carbon sinks into carbon sources. A new model better predicts spread of the adelgid in the south and west of the range of hemlock, but still under-predicts its spread in the north and east. Whether these underpredictions result from inadequately modeling accelerating climate change or accounting for people inadvertently moving the adelgid into new locales needs further study. Ecosystem models of adelgid-driven hemlock dynamics have consistently forecast that forest carbon stocks will be little affected by the shift from hemlock to early-successional mixed hardwood stands, but these forecasts have assumed that the intermediate stages will remain carbon sinks. New forecasting models of adelgid-driven hemlock decline should account for observed abrupt changes in carbon flux and ongoing and accelerating human-driven land-use and climatic changes.


2013 ◽  
Vol 15 (7) ◽  
pp. 2043-2062 ◽  
Author(s):  
Carol D. von Dohlen ◽  
Usha Spaulding ◽  
Kathleen Shields ◽  
Nathan P. Havill ◽  
Cristina Rosa ◽  
...  

1998 ◽  
Vol 38 (7) ◽  
pp. 263-270 ◽  
Author(s):  
C. C. C. Cheung ◽  
P. K. S. Lam

The effects of cadmium on early life stages of a freshwater snail, Physa acuta (Draparnaud), were investigated. The 24- and 48-hour LC50 for embryos were 1.27 mg/l (95% confidence interval: 1.13 - 1.42) and 0.85 mg/l (0.71 - 1.01), respectively. The 24- and 48-hour LC50 for juveniles were 1.32 mg/l (1.13 - 1.54) and 1.05 mg/l (0.81 - 1.36), respectively. An increase in cadmium concentrations at sublethal levels resulted in a significant reduction in embryo growth rate and embryo hatchability. Developmental deformities of the embryos were also observed. The NOEC and LOEC for embryonic growth were 0.32 and 0.50 mg/l, respectively, and the LOEC for hatchability was 0.13 mg/l. These results suggest that embryonic growth and hatchability are useful endpoints in chronic toxicity tests. In addition, the potential use of early life stages of pulmonate snails in ecotoxicological tests is discussed.


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