An overview of biological control programs against invasive insects and plants for protection of forested ecosystems in the United States

2016 ◽  
Author(s):  
Sharlene E. Sing
Keyword(s):  
United States ◽  
Biological Control ◽  
The United States ◽  
Invasive Insects ◽  
Control Programs ◽  
Forested Ecosystems

Assessing the role of generalist predators in the biological control of alfalfa weevil (Coleoptera: Curculionidae)

2017 ◽  
Vol 149 (4) ◽  
pp. 525-533 ◽  
Author(s):  
Tatyana A. Rand
Keyword(s):  
United States ◽  
Biological Control ◽  
Experimental Work ◽  
United States Of America ◽  
Acyrthosiphon Pisum ◽  
The United States ◽  
Generalist Predators ◽  
Alfalfa Weevil ◽  
Exclusion Experiment ◽  
Predator Exclusion

AbstractAlfalfa weevil (Coleoptera:Curculionidae) is a major pest of alfalfa throughout the United States of America. Biological control research has disproportionately focussed on introduced parasitoids. Generalist predators may also be important, but experimental work evaluating their impacts is lacking. I combined a cross-site survey with a predator exclusion experiment to identify key predators, and test for impacts on weevil survival and plant defoliation levels in Montana and North Dakota, United States of America. Spiders (Araneae) dominated the complex, followed by Nabidae (Hemiptera) and Coccinellidae (Coleoptera). None of the dominant predators showed aggregative responses to weevil (Hypera postica (Gyllenhal); Coleoptera: Curculionidae) or pea aphid (Acyrthosiphon pisum (Harris); Hemiptera: Aphididae) densities across 10 sites surveyed. However, weevil densities were positively correlated with both coccinellid and nabid densities across transects at the experimental site. Thus, predator groups traditionally associated with aphids can show strong aggregative numerical responses to alfalfa weevil larvae at smaller scales. Predator exclusion revealed no significant predator effects on larval survival or alfalfa damage. However, final densities of pea aphids were significantly higher in exclusion treatments relative to controls. The results suggest that even under conditions where predators exert significant pressure on aphids, they may still have minimal impacts on weevils. Additional experimental work is necessary to determine the broader potential of generalist predators as alfalfa weevil control agents.

scholarly journals Laurel Wilt: Current and Potential Impacts and Possibilities for Prevention and Management

Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 181
Author(s):  
Rabiu O. Olatinwo ◽  
Stephen W. Fraedrich ◽  
Albert E. Mayfield
Keyword(s):  
United States ◽  
Tree Mortality ◽  
The United States ◽  
Persea Americana ◽  
Laurel Wilt ◽  
Important Species ◽  
Invasive Insects ◽  
Raffaelea Lauricola ◽  
Redbay Ambrosia Beetle ◽  
The Impact

In recent years, outbreaks of nonnative invasive insects and pathogens have caused significant levels of tree mortality and disturbance in various forest ecosystems throughout the United States. Laurel wilt, caused by the pathogen Raffaelea lauricola (T.C. Harr., Fraedrich and Aghayeva) and the primary vector, the redbay ambrosia beetle (Xyleborus glabratus Eichhoff), is a nonnative pest-disease complex first reported in the southeastern United States in 2002. Since then, it has spread across eleven southeastern states to date, killing hundreds of millions of trees in the plant family Lauraceae. Here, we examine the impacts of laurel wilt on selected vulnerable Lauraceae in the United States and discuss management methods for limiting geographic expansion and reducing impact. Although about 13 species belonging to the Lauraceae are indigenous to the United States, the highly susceptible members of the family to laurel wilt are the large tree species including redbay (Persea borbonia (L.) Spreng) and sassafras (Sassafras albidum (Nutt.) Nees), with a significant economic impact on the commercial production of avocado (Persea americana Mill.), an important species native to Central America grown in the United States. Preventing new introductions and mitigating the impact of previously introduced nonnative species are critically important to decelerate losses of forest habitat, genetic diversity, and overall ecosystem value.

scholarly journals Fungicide Resistance Management Guidelines for the Control of Tomato Diseases in the Mid-Atlantic and Northeast Regions of the United States

2010 ◽  
Vol 11 (1) ◽  
pp. 32 ◽  
Author(s):  
Christian A. Wyenandt ◽  
Steven L. Rideout ◽  
Beth K. Gugino ◽  
Margaret T. McGrath ◽  
Kathryne L. Everts ◽  
...  
Keyword(s):  
United States ◽  
Fungicide Resistance ◽  
Resistance Management ◽  
The United States ◽  
Management Tool ◽  
Fresh Market ◽  
Management Guidelines ◽  
Control Programs ◽  
Action Committee ◽  
Tomato Diseases

Foliar diseases and fruit rots occur routinely on tomato, an important crop grown throughout the Mid-Atlantic and Northeast regions of the United States where it is produced for both fresh-market and processing. To enable these tomato growers to more effectively manage economically important diseases, a fungicide resistance management table has been developed which promotes the importance of understanding FRAC (Fungicide Resistance Action Committee) codes and provides an integrated pest management tool for tomato growers which will allow them to develop season-long disease control programs with an emphasis on fungicide resistance management. Accepted for publication 19 July 2010. Published 27 August 2010.

scholarly journals First Report of Stem Canker of Salsola tragus Caused by Diaporthe eres in Russia

Plant Disease ◽  
2009 ◽  
Vol 93 (1) ◽  
pp. 110-110 ◽  
Author(s):  
T. Kolomiets ◽  
Z. Mukhina ◽  
T. Matveeva ◽  
D. Bogomaz ◽  
D. K. Berner ◽  
...  
Keyword(s):  
United States ◽  
Biological Control ◽  
Biological Control Agent ◽  
Aqueous Suspension ◽  
Stem Canker ◽  
The United States ◽  
Invasive Weed ◽  
Voucher Specimen ◽  
First Report ◽  
Stem Lesions

Salsola tragus L. (Russian thistle) is a problematic invasive weed in the western United States and a target of biological control efforts. In September of 2007, dying S. tragus plants were found along the Azov Sea at Chushka, Russia. Dying plants had irregular, necrotic, canker-like lesions near the base of the stems and most stems showed girdling and cracking. Stem lesions were dark brown and contained brown pycnidia within and extending along lesion-free sections of the stems and basal portions of leaves. Diseased stems were cut into 3- to 5-mm pieces and disinfested in 70% ethyl alcohol. After drying, stem pieces were placed into petri dishes on the surface of potato glucose agar. Numerous, dark, immersed erumpent pycnidia with a single ostiole were observed in all lesions after 2 to 3 days. Axenic cultures were sent to the Foreign Disease-Weed Science Research Unit, USDA, ARS, Ft. Detrick, MD for testing in quarantine. Conidiophores were simple, cylindrical, and 5 to 25 × 2 μm (mean 12 × 2 μm). Alpha conidia were biguttulate, one-celled, hyaline, nonseptate, ovoid, and 6.3 to 11.5 × 1.3 to 2.9 μm (mean 8.8 × 2.0 μm). Beta conidia were one-celled, filiform, hamate, hyaline, and 11.1 to 24.9 × 0.3 to 2.5 μm (mean 17.7 × 1.2 μm). The isolate was morphologically identified as a species of Phomopsis, the conidial state of Diaporthe (1). The teleomorph was not observed. A comparison with available sequences in GenBank using BLAST found 528 of 529 identities with the internal transcribed spacer (ITS) sequence of an authentic and vouchered Diaporthe eres Nitschke (GenBank DQ491514; BPI 748435; CBS 109767). Morphology is consistent with that of Phomopsis oblonga (Desm.) Traverso, the anamorph of D. eres (2). Healthy stems and leaves of 10 30-day-old plants of S. tragus were spray inoculated with an aqueous suspension of conidia (1.0 × 106 alpha conidia/ml plus 0.1% v/v polysorbate 20) harvested from 14-day-old cultures grown on 20% V8 juice agar. Another 10 control plants were sprayed with water and surfactant without conidia. Plants were placed in an environmental chamber at 100% humidity (rh) for 16 h with no lighting at 25°C. After approximately 24 h, plants were transferred to a greenhouse at 20 to 25°C, 30 to 50% rh, and natural light. Stem lesions developed on three inoculated plants after 14 days and another three plants after 21 days. After 70 days, all inoculated plants were diseased, four were dead, and three had more than 75% diseased tissue. No symptoms occurred on control plants. The Phomopsis state was recovered from all diseased plants. This isolate of D. eres is a potential biological control agent of S. tragus in the United States. A voucher specimen has been deposited with the U.S. National Fungus Collections (BPI 878717). Nucleotide sequences for the ribosomal ITS regions (ITS 1 and 2) were deposited in GenBank (Accession No. EU805539). To our knowledge, this is the first report of stem canker on S. tragus caused by D. eres. References: (1) B. C. Sutton. Page 569 in: The Coelomycetes. CMI, Kew, Surrey, UK, 1980. (2) L. E. Wehmeyer. The Genus Diaporthe Nitschke and its Segregates. University of Michigan Press, Ann Arbor, 1933.

scholarly journals Leaf Anthracnose, a New Disease of Swallow-Worts Caused by Colletotrichum lineola from Russia

Plant Disease ◽  
2011 ◽  
Vol 95 (12) ◽  
pp. 1586-1586 ◽  
Author(s):  
D. Berner ◽  
C. Cavin ◽  
Z. Mukhina ◽  
D. Kassanelly
Keyword(s):  
United States ◽  
Biological Control ◽  
Dna Sequences ◽  
Aqueous Suspension ◽  
Science Research ◽  
The United States ◽  
Research Unit ◽  
Leaf Spots ◽  
Pure Cultures ◽  
Appressoria Formation

Black swallow-wort, Vincetoxicum nigrum (L.) Moench (= Cynanchum louiseae Kartesz & Gandhi), and pale swallow-wort, V. rossicum (Kleopow) Borhidi (= Cynanchum rossicum (Kleopow) Borhidi), are invasive plants belonging to the family Apocynaceae and are the targets of biological control efforts to control their spread in the United States. In 2010, a disease on a related species, V. scandens Sommier & Levier, was observed in the Krasnodar area of Russia. Disease symptoms were many small, dark red-to-purple leaf spots, approximately 2 to 5 mm in diameter, with white centers. Leaf spots were found on the upper leaf surface. Leaf tips and margins of leaves bearing many of these spots were necrotic. Symptomatic leaves were collected and sent to the BSL-3 containment facility at the Foreign Disease-Weed Science Research Unit (FDWSRU) of the USDA, ARS in Frederick MD. Surface-disinfested symptomatic leaves were incubated at 20 to 25°C in sterile moist chambers. After several days, acervuli and brown setae were observed inside the leaf spots. Pure cultures, designated FDWSRU 10-002, were obtained by transferring spore masses with sterile glass needles onto 20% V8 juice agar. Seeds of V. scandens, collected in Russia, were placed in a freezer at –20°C for 6 weeks and then germinated in sterile petri plates on moist filter paper. The seedlings were then transplanted and grown in a 20°C greenhouse under 12 h of light. Koch's postulates were fulfilled as follows: 2-month-old plants each of V. scandens, V. nigrum, and V. rossicum were inoculated with spores from 2-week-old cultures of isolate 10-002. Plants were inoculated by spraying an aqueous suspension of 106 spores per ml onto each plant until all leaves were wet. Plants were placed in 20 to 24°C dew chambers for 18 h and then placed in a 20°C greenhouse. Two weeks later, diseased leaves with the same symptoms observed in the field were harvested from each species, and the fungus was reisolated from seven of seven inoculated V. scandens plants, one of two V. nigrum plants, and four of four V. rossicum plants. Measurements of fungus fruiting structures were taken from cultures grown on synthetic nutrient-poor agar (SNA) (1). Conidiophores were brown, septate, and branched. Conidia were one-celled, hyaline, smooth walled, ovoid to oblong, falcate, and 20.1 to 26.2 × 1.7 to 3.6 μm (mean ± s.d. = 23.5 ± 1.3 × 2.6 ± 0.4 μm). Lengths of the conidia conformed to the description of Colletotrichum lineola Corda (1), but the conidia were slightly narrower than described. To induce appressoria formation, approximately 104 conidia were placed on sterile dialysis membranes on top of SNA in petri dishes that were wrapped in foil and incubated at 24°C for 24 h. After this time, appressoria were observed with a microscope at ×400 magnification. The appressoria were dark brown, smooth walled, ellipsoidal, and 5.5 to 25.5 × 3.6 to 12.1 μm (mean ± s.d. = 13.4 ± 4.0 × 7.3 ± 2.1 μm), which conformed to the description of appressoria of C. lineola Corda (1). DNA sequences of ITS1, 5.8S, and ITS2 were submitted to GenBank (No. HQ731491), and after BLAST analysis, aligned 100% to 15 previously identified isolates of C. lineola in GenBank. Voucher specimens of the fungus have been deposited in the U.S. National Fungus Collection and were designated as BPI 881105 and BPI 881106. Host range and efficacy tests are planned to determine the suitability of C. lineola for biological control of swallow-worts in the United States. Reference: (1) U. Damm et al. Fungal Divers. 39:45, 2009.

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