scholarly journals Impact of Imidacloprid for Control of Hemlock Woolly Adelgid on Nearby Aquatic Macroinvertebrate Assemblages

2011 ◽  
Vol 35 (1) ◽  
pp. 26-32 ◽  
Author(s):  
Melissa A. Churchel ◽  
James L. Hanula ◽  
C. Wayne Berisford ◽  
James M. Vose ◽  
Mark J. Dalusky

Abstract Imidacloprid, a systemic insecticide that acts on the nervous system, is currently being used to control hemlock woolly adelgid (Adelges tsugae Annand), which is damaging hemlock trees. The objective of this study was to determine whether soil injection with imidacloprid for hemlock woolly adelgid control near streams adversely affects aquatic invertebrates. Eastern hemlocks (Tsuga canadensis) in the watersheds surrounding four streams in the southern Appalachian region of Georgia and North Carolina were treated with imidacloprid. Addie Branch was the only stream that exhibited a possible effect from imidacloprid treatment. However, the data followed the same pattern as the other treatment streams, but with a more pronounced decrease in taxa due to adult emergence. Only a trace amount of imidacloprid was detected in one water sample from Holcomb Tributary over a period of 2 years, and no effect was observed on the aquatic macroinvertebrates in that stream. However, caution should be used when applying these results to other areas with different soil types (e.g., low organic matter content) that may not bind imidacloprid as tightly. Our results indicate that soil injections of imidacloprid can safely be used in the southern Appalachian area to control hemlock woolly adelgid.

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.


Weed Science ◽  
1969 ◽  
Vol 17 (1) ◽  
pp. 69-77 ◽  
Author(s):  
R. P. Upchurch ◽  
F. T. Corbin ◽  
F. L. Selman

Rates of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron) up to 2.4 lb/A were applied as layby weed control treatments for cotton (Gossypium hirsutum L., var. Coker 100-A) in association with 0.0 or 1.0 lb/A of diuron as a preemergence treatment. Soybeans (Glycine max L. Merr., var. Lee) were grown as an alternate year rotational crop or as a rotational crop after cotton had been grown 3 years under diuron treatment. Similar rotational systems were evaluated in which corn (Zea mays L., var. Coker 71), tobacco (Nicotiana tabacum L., var. NC-95 or NC-2326), wheat (Triticum sativum Lam., var. Wakeland), cotton, and peanuts (Arachis hypogaea L., var. NC-2) served as the rotational crops in place of soybeans. In this mixed crop rotation, herbicidal treatments were 1.0 lb/A of diuron applied as a preemergence treatment plus 0.6 or 1.2 lb/A of diuron or 1.2 lb/A of 3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea (linuron) applied as a layby treatment. Two soil types near Rocky Mount, North Carolina were used. Herbicidal residues were determined by bioassay analyses in the fourth year of the experiment and by evaluating crops grown in the years when no herbicides were applied. Diuron residues were greater on Duplin soil than on Norfolk soil, but residues on Duplin soil were less phytotoxic to crops than those on Norfolk soil. The higher organic matter content of Duplin soil (1.2 vs 0.6%) is cited to account for both of these observations. When diuron was applied to Norfolk soil as a preemergence treatment at 1.0 lb/A plus 0.6 lb/A as a layby treatment, the residues frequently injured wheat, peanuts, and tobacco grown subsequently. Soybeans sometimes were injured by this treatment, but corn and cotton tolerated it even when the layby rate was increased to 1.2 lb/A. At equal layby rates, linuron produced residues of less consequence than diuron. At the higher application rates, greater residues occurred following 3 years of application than where application had been on an alternate year basis.


Weed Science ◽  
1976 ◽  
Vol 24 (1) ◽  
pp. 120-126 ◽  
Author(s):  
G. W. Harrison ◽  
J. B. Weber ◽  
J. V. Baird

Preemergence applications of atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine], chloramben (3-amino-2,5-dichlorobenzoic acid), fluometuron [1,1-dimethyl-3-(α,α,α-trifluro-m-tolyl)urea], propachlor (3-chloro-N-isopropylacetanilide), and trifluralin (α,α,α-trifluro-2,6-dinitro-N,N-dipropyl-p-toluidine) were compared in 10 North Carolina soils and the relationship of activity to soil physical and chemical properties appraised. Oats (Avena sativaL. ‘Carolee’) were used as the indicator plant in bioassays under greenhouse conditions. Fifteen soil properties were measured and correlated with herbicide I50(50% fresh weight inhibition) values. Organic matter was the soil variable most highly correlated with herbicide phytotoxicity. There was an inverse relationship between herbicide water solubility and inactivation by organic matter. Volume weight determinations and water holding capacity values (0.1 bar) provided relatively good estimates of soil organic matter contents, but were not as highly related to herbicide activity as organic matter content.


2011 ◽  
Vol 29 (4) ◽  
pp. 197-204 ◽  
Author(s):  
Shimat V. Joseph ◽  
S. Kristine Braman ◽  
Jim Quick ◽  
James L. Hanula

Abstract Hemlock woolly adelgid (HWA), Adelges tsugae Annand is a serious pest of eastern and Carolina hemlock in the eastern United States. A series of experiments compared commercially available and experimental insecticides, rates, application methods and timing for HWA control in Georgia and North Carolina. Safari 20 SG (dinotefuran) provided an average of 79 to 87% suppression of adelgid populations within one month after spring application. Arena 50 W (clothianidin) and Merit 75 WP (imidacloprid) were slower acting but provided longer-term adelgid suppression than dinotefuran. However, 26 months after application in spring 2006 HWA re-colonized trees treated with dinotefuran while imidacloprid treatments were still effective. High volume treatments like soil drenches of dinotefuran did not improve adelgid control over low volume applications such as soil injection. Evaluation in July 2008 of a fall 2007 application of Tristar 30 SG (acetamiprid) using arborjet trunk injectors showed no reduction of nymphal populations. Treatment timing and rates did not affect HWA relative to untreated check. The Xytect 75 WSP (imidacloprid) soil injection treatments applied during May, August, or November 2007 and Xytect root-flare micro injection system treatment in November 2007 provided 99 to 100% control in all treatments.


Author(s):  
O. A. Lipatnikova

The study of heavy metal speciation in bottom sediments of the Vyshnevolotsky water reservoir is presented in this paper. Sequential selective procedure was used to determine the heavy metal speciation in bottom sediments and thermodynamic calculation — to determine ones in interstitial water. It has been shown that Mn are mainly presented in exchangeable and carbonate forms; for Fe, Zn, Pb и Co the forms are related to iron and manganese hydroxides is played an important role; and Cu and Ni are mainly associated with organic matter. In interstitial waters the main forms of heavy metal speciation are free ions for Zn, Ni, Co and Cd, carbonate complexes for Pb, fulvate complexes for Cu. Effects of particle size and organic matter content in sediments on distribution of mobile and potentially mobile forms of toxic elements have been revealed.


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