Biological control (1995) 5: 113-122.
A COMPARISON OF VARIOUS APPROACHES FOR EVALUATING POTENTIAL BIOLOGICAL CONTROL AGENTS USING INSECTS ON Lythrum salicaria
Bernd Blossey
International Institute of Biological Control
European Station I, Chemin des Grillons
CH-2800 Delémont, Switzerland
ABSTRACT
The selection of biological weed control agents that become successfully established and provide good control has prvoen difficult. During a program aimed at controlling Lythrum salicaria, a perennial Eurasion plant invading North American wetalnds, various approaches developed for prioritizing potential biocontrol agents were utilized to rank nine insect species. In addition, species were ranked according to characteristics of successful agents identified by the analysis of past biological weed control programs. Different approached produced contradictory results. Therefore, species selected for host-specificity screening and release were ranked according to thier impact on plant perfomance, feeding niche, and distribution. Hylobius transversovittatus, a root-boring weevil, was given the highest priority, followed by two leaf-eating beetles, Galerucella calmariensis and Galerucella pusilla. Curently existing protocols for selecting the most promising candidates from an existing species pool are not satisfactory. Carefully planned release and follow-up studies on the effect of single and multiple species herbivory as well as type of herbivore feeding on plant performance and population dynamics can eventually improve the sucess of biological weed control.
Proceedings of the Eighth International Symposium on Biological Control of Weeds
2-7 February, 1992, Lincoln University, Canterbury, New Zealand
IMPACT OF Galerucella pusilla Duft. AND G. calmariensis L. (COLEOPTERA: CHRYSOMELIDAE) ON FIELD POPULATIONS OF PURPLE LOOSESTRIFE (Lythrum salicaria)
Bernd Blossey
IIBC, European Station, 1, Chemin des Grillons
2800 Delémont, Switzerland
ABSTRACT
Lythrum salicaria, a perennial weed of Eurasian origin, was introduced into North America some 200 years ago. It's spread into wetlands in the northern parts of the US and Southern Canada degraded the value of infested areas for wildlife. A biocontrol programme was initiated by USDA and US Fish and Wildlife Service and the leaf-feeding chrysomelids Galerucella calmariensis and G. pusilla were selected for further study in Europe. Investigations in Northern Germany on the impact of both species at five study site between 1988 and 1990 provided data on interactions within the native range of their host plant. On three of the five sites investigated the impact of these herbivores caused high plant mortality, reduced shoot growth, suppressed flowering and reducted seed output to less than 1%. Attack strongly affected the compensation ability of plants in consecutive years, but even previously unattacked plants were unable to compensate for damage caused by three larvae per cm shoot. The data collected demonstrate that the two Galerucella species are key factors in the population dynamics of purple loosestrife and therefore suitable agents for successful biological control in North America.
OIKOS, in press
COEXISTENCE OF TWO LEAF-BEETLES IN THE SAME FUNDAMENTAL NICHE.
I. DISTRIBUTION, ADULT PHENOLOGY AND OVIPOSITION
Bernd Blossey
New York Cooperative Fish and Wildlife Research Unit
Department of Natural Resources, Fernow Hall
Cornell University, Ithaca, New York 14853, USA
Email: bb22@cornell.edu
ABSTRACT
This study investigated the coexistence of two leaf-beetles, Galerucella calmariensis and G. pusilla, on purple loosestrife (Lythrum salicaria). G. pusilla and G. calmariensis share their distribution on a continental, regional, and local scale. Models of stable coexistence of two competitors assume access of inferior species to resources or refuges that are temporarily or spatially unexploited by the superior species. Field and laboratory studies indicated that both species have inclusive fundamental niches on their host plant. Cytological studies and crossing experiments confirmed their status as true, reproductively isolated species. G. calmariensis and G. pusilla showed no differences in adult phenology, winter mortality, colonization pattern nor oviposition, thus no temporal variation in resource use. Adults aggregated at the same sites and on the same host plant individuals and their distributions are not independent. Aggregation or differences in resource use do not appear to play an important role in the coexistence of G. calmariensis and G. pusilla. This study indicated that both species have identical competitive abilities.
New York Fish Cooperative Fish and Wildlife Research Unit Newsletter
March 1995
INSTRUCTIONS FOR FIELD RELEASE OR PROPAGATION OF Hylobius transversovittatus FOR THE BIOLOGICAL CONTROL OF PURPLE LOOSESTRIFE (Lythrum salicaria)
B. Blossey and R. A. Malecki
New York Fish and Wildlife Research Unit
Department of Natural Resources
Cornell University, Ithaca, NY 14853
NO ABSTRACT
Journal of Ecological Enotomology 1995, in press
PERFORMANCE OF A LEAF-BEETLE ON DIFFERENT NORTH AMERICAN POPULATIONS OF PURPLE LOOSESTRIFE
Bernd Blossey and Marjolein Schat
New York Cooperative Fish and Wildlife Research Unit
Department of Natural Resources
Fernow Hall, Cornell University
Ithaca, New York 14853 U.S.A.
ABSTRACT
1. The success of a biological weed control programme depends on the ability of control agents to develop on various genotypes of their host plants, thereby reducing the competitive ability of their target plant species. We studied the performance of the chrysomelid beetle Galerucella calmariensis, introduced as a biological control agent of Lythrum salicaria, on plants from three different North American populations.
2. Plants for the experiments were obtained from Ithaca, New York; St. Paul, Minnesota; and Salem, Oregon, representing different climates and colonization histories. We studied the survival and impact of G. calmariensis at three herbivore densities with plants grown under identical conditions at Ithaca.
3. Plant growth and biomass allocation patterns were significantly different between the three tested populations. Survival rates of the leaf feeder (egg to adult) were not significantly different between sites or between herbivore attack levels. Herbivory caused significant reductions in plant height, leaf, shoot, root, and total plant biomass with increase in attack levels. We found no significant interaction of herbivory and plant origin.
4. Plants compensated for the loss of photosynthetic tissued by replacing foliage at the expense of below ground storage, thus, herbivory altered the biomass allocation pattern of L. salicaria. This might have important implications for other control agents attacking the roots of L. salicaria.
Weed Science, 1994. Volume 42:134-140
HOST SPECIFICITY AND ENVIRONMENTAL IMPACT OF TWO LEAF BEETLES (Galerucella calmariensis and G. pusilla) FOR BIOLOGICAL CONTROL OF PURPLE LOOSESTRIFE (Lythrum salicaria)
Bernd Blossey, Dieter Schroeder, Stephen D. Hight, and Richard
A. Malecki
Address of first author:
New York Cooperative Fish & Wildlife Research Unit
Fernow Hall, Cornell University, Ithaca, NY 14853
ABSTRACT
Many prime wetlands in North America have been degraded following encroachment by the exotic plant purple loosestrife. Conventional methods are unsuccessful in providing long-term control. Host specificity studies demonstrated the suitability of two leaf beetles, Galerucella calmariensis and G. pusilla, as biological weed control agents. Adults oviposited only on plants within the genus Lythrum. The only species other than purple loosestrife where adult feeding and oviposition occurred and that supported successful larval development was winged lythrum. Swamp loosestrife and winged lythrum may be vulnerable to limited attack by newly emerged teneral adults. Evaluation of the potential environmental impact of the two leaf beetles showed that benefits of an introduction out weigh potential risks to winged lythrum or swamp loosestrife. Their field release was approved in 1992.
Biological Control (1995) 5: 47-53
HOST SPECIFICITY OF THREE POTENTIAL BIOLOGICAL WEED CONTROL AGENTS ATTACKING FLOWERS AND SEEDS OF Lythrum salicaria (PURPLE LOOSESTRIFE)
Bernd Blossey and Dieter Shroeder
International Institute of Biological Control
European Station I, Chemin des Grillons
CH-2800 Delémont, Switzerland
ABSTRACT
Lythrum salicaria is a Eurasian herbaceous perennial that has become a serious invader of wetalnds in the United States and Canada. Dense monospecific stands replace a diverse native flora resulting in the degradation of theses wetland habitats. There are presently no satisfactory means of control. Biological control offers the most promising method of resolving this problem. A root-mining weevil and two leaf-eating chrysomelids from Europe were released in North America in 1992. The host specificity of three additional flower- and seed-eating species was investigated. The two weevils, Nanophyes marmoratus and N. brevis, have a wide geographic and ecological range. Both develop exclusively on Lythrum salicaria within its native European range and were found to be highly host specific during screen tests. Minor adult feeding was observed in no-choice tests on a few other speices within Lythraceae. Successful larval development was restricted to purple loosestrife. The only known field host of the third species, the gall midge, Bayeriola salicariae, is purple loosestrife. Oviposition and successful larval development of B. salicariae in cages and open field occured on potted test plants of another three Lythrum species. The introduction of N. marmoratus and N. brevis into North America is expected to futher reduce seed output and lessen the competitive ability of purple loosestrife. Their introduction was approved in 1994.
July 1992
THE DESIRABILITY OF USING BIOCONTROL AGAINST PURPLE LOOSESTRIFE IN CANADA
Rosemarie DeClerck-Floate
Agriculture Canada
Box 3000 Main
Lethbridge, Alberta T1J 4B1 Canada
ABSTRACT
Purple loosestrife, Lythrum salicaria L. is an introduced perennial from Eurasia that is rapidly invading and reducing the quality of wetland habitats in temperate areas of N.A., including southern Canada. No effective means of control currently exist in Canada except in cases where the infestations are small and isolated. Classical biological control is the best option, and promises to be the most environmentally and economically satisfactory. Three insect species from Europe recently have been screened for host specificity and approved for release in the U. S. for control of purple loosestrife. The root-feeding weevil, Hylobius transversovittatus (Goeze)(Curculionidae), and the leaf-feeding beetles, Galerucella calmariensis (L.) and G. pusilla (Duft.)(Chrysomelidae) also are recommended for release in Canada based on their narrow host ranges, climatic origins compatible with those of Canada, and potential for causing extensive damage to L. salicaria. Because of potential conflicts of interest arising from Canadian beekeeping and horticultural industries, it also is suggested that initial releases only be made in provinces where formal, provincial approval has been given.
Natural Areas Journal Vol. 11(3), 1991; 129 - 142.
PAST SUCCESSES AND CURRENT PROSPECTS IN BIOLOGICAL CONTROL OF WEED IN THE UNITED STATES AND CANADA
C. Jack DeLoach
US Department of Agriculture
Agricultural research service
808 East Blackland Road
Temple, Texas 76502
The introduction of insects or pathogens has safely controlled many weeds in over 50 countries during the past 100 years. In Hawaii, nine weeds have been completely or substantially controlled since 1902. In continental North America since 1945, St. Johnswort (Hypercium perforatum), puncturevine (Tribulus terrestris), tansy ragwort (Senecio jacobaea), musk thistle (Carduus thoermeri), and skeletonweed (Chondrilla juncea) have been controlled in rangelands; and alligatorweed (Alternanthera philoxeroides) and waterhyacinth (Eichhornia crassipes) have been controlled in aquatic areas. Prospects are good for successful control of knapweeds and yellow starthistle (Centaurea spp.), leafy spurge (Euphorbia esula), toadflaxes (Linaria spp.), and snakeweeds (Gutierrezia spp.) in rangelands; for waterlettuce (Pistia stratiotes) and hydrill (Hydrilla verticillata) in aquatic sites; and for melaleuca tree (Melaleuca quinquenervia), and purple loosestrife (Lythrum salicaria), Brazilian peppertree (Schinus terebinthefolius), and saltcedar (Tamarix spp.) in natural areas. Many other weeds have the potential for biological control. Biological control reduces the abundance of selected weeds but does not harm nontarget (including rare) species; it is non-polluting. Because of it permanence and relatively low cost, the introductory approach is more appropriate in natural areas than is augmentation. The ecological consequences of biological control of pests and of vegetation change in natural areas, and future opportunities and directions for biological control of weeds are discussed.
Natural Areas Journal 11(3): 151-157
PROSPECTS FOR A CLASSICAL BIOLOGICAL CONTROL PROJECT AGAINST PURPLE LOOSESTRIFE (Lythrum salicaria L.)
Stephen D. Hight and John J. Drea, Jr.
Insect Biocontrol Laboratory, PSI
Agricultural Research Service, USDA
10300 Baltimore Avenue
BARC-East, Building 406
Beltsville, Maryland 20705-2350
ABSTRACT
Purple loosestrife, Lythrum salicaria, was introduced into North America from Europe at the beginning of the nineteenth century. The plant has progressively spread westward and now occurs throughout the northern half of the United States and southern Canada. It aggressively invades wetlands and displaces native vegetation. The high cost and transitory nature of various chemical and cultural control methods have led to the development of a classical biological control program against purple loosestrife. Research has shown that three phytophagous European insects--a weevil, Hylobius tranversovittatus, and two leaf-eating beetles, Galerucella calmariensis and G. pusilla--are very host-specific and highly damaging to the plant. These insects are being considered for release into North America in an attempt to control L. salicaria. If these insects are as effective as research indicates, the outlook for successful classical biological control against purple loosestrife is excellent.
Environmental Entomology 24(4): 967-977 (1995)
ESTABLISHMENT OF INSECT BIOLOGICAL CONTROL AGENTS FROM EUROPE AGAINST Lythrum salicaria IN NORTH AMERICA
Stephen D. Hight, Bernd Blossey, John Laing, and Rosemarie
Declerck-Floate
Address of first author:
Insect Biocontrol Laboratory
USDA-ARS, Beltsville, MD 20705
ABSTRACT
Three European biological control agents of the exotic, wetland perennial plant purple loosestrife, Lythrum salicaria L., were released in North America in 1992 and 1993. Two leaf-feeding beetles, Galerucella calmariensis L. and G. pusilla Duftschmidt, from 2 climatically different source populations in Germany, were released in 10 different states and 6 Canadian provinces. The importance for establishment success of climatic preadaption, number of individuals released, release of laboratory or field-collected material, and confinement of release were investigated in a series of experimental releases. Both Galerucella species became established at all 1992 release sites regardless of their origin or release method. Higher survival in cages was found for releases of 600 beetles compared with releases of 200 beetles. The amount of litter, number of standing dead stems, or host-plant density did not affect establishment. A root-feeding weevil, Hylobius transversovittatus Goeze, was released in 9 states and 2 Canadian Provinces, and established in the field in 6 states and both provinces. The 3 species successfully passed the most critical phase for establishment in North America; production of the generation following release.
Transactions of the 59th North American Wildlife & Natural Resources Conference (1994); pages 400 - 404
INSECT BIOLOGICAL WEED CONTROL: AN IMPORTANT AND UNDERUTILIZED MANAGEMENT TOOL FOR MAINTAINING NATIVE PLANT COMMUNITIES THREATENED BY EXOTIC PLANT INTRODUCTIONS
Richard Malecki and Bernd Blossey
New York Cooperative Fish and Wildlife Research Unit
Ithaca, New York
NO ABSTRACT
Bioscience Vol. 43 (10), 1993; 680 - 686.
BIOLOGICAL CONTROL OF PURPLE LOOSESTRIFE: A CASE FOR USING INSECTS AS CONTROL AGENTS, AFTER RIGOROUS SCREENING, AND FOR INTEGRATING RELEASE STRATEGIES WITH RESEARCH
Richard A. Malecki*, Bernd Blossey, Stephen D. Hight, Dieter
Schroeder, Loke T. Kok, and Jack. R. Coulson
*US Fish and Wildlife Service
New York Cooperative Fish and Wildlife Research Unit
Cornell University
Ithaca, New York 14853
NO ABSTRACT
Natural Areas Journal 11(3) : 148-150
HISTORY OF PURPLE LOOSESTRIFE (Lythrum salicaria L.) BIOLOGICAL CONTROL EFFORTS
Daniel Q. Thompson
623 Del Norte Place
Forte Collins, Colorado 80521 USA
Retired U. S. Fish and Wildlife Service
(Paper presented at a session on the exotic species control at the Sixteenth Annual Natural Areas Conference, October 17-20, 1989 in Knoxville, Tennessee.)
ABSTRACT
After a relatively slow beginning on the northeastern maritime coast, purple loosestrife (Lythrum salicaria L.) has spread across temperate North America to the West Coast. It has displaced native wetland vegetation in pastures, marshes, and riparian hay meadows. Thus far, all methods of cultural, mechanical, and chemical controls have been unsatisfactory for widespread use in natural areas. An attempt to establish a biological control program in the late 1960's failed because there was not enough information to justify the cost of the program, and because regional interest was low in this weed, which was so well-established as to seem part of the natural setting. Subsequent research on purple loosestrife continued part-time and consisted of field surveys and literature searches to establish the background of the weed and its potential impact on the native biota. In 1968, a questionnaire on purple loosestrife spread and impact was mailed to wetland managers throughout the Northeast and Midwest. The response formed the beginnings of a purple loosestrife monitoring network that eventually succeeded in obtaining congressional support for the biological control of purple loosestrife.
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