Fenusa Pusilla Research Articles

Biological Control ofFenusa pusilla(Hymenoptera: Tenthredinidae) in the Northeastern United States: A Thirty-Four Year Perspective on Efficacy

ABSTRACT Parasitoid releases against the birch leafminer Fenusa pusilla (Lepeletier) (Hymenoptera: Tenthredinidae) in eastern North America began in 1974, with releases in eastern Canada, followed by others in the Middle Atlantic States and New England. Of 4 parasitoids released, only 1, the ichneumonid Lathrolestes nigricollis (Thompson), established and spread widely. Studies of its preliminary impacts were made in several locations in the 1980s and 1990s, but full impact of the parasitoid on host density was not yet achieved in that period. Here we report results of surveys in 7 states (MA, CT, RI, NY, PA, NJ, DE) in 2007 documenting the current birch leaf miner levels (as % of leaves mined in spring) and parasitism. Survey results show that the pest has declined dramatically to barely detectable levels in 5 states (MA, CT, RI, NY, PA) but that in southern NJ, the pest remains abundant (ca 50% leaves mined) despite significant parasitism levels. Survey results, in context with previous evaluations made...

Effectiveness of Interspecific Hybridization for Incorporating Birch Leafminer (Fenusa pusilla) Resistance into White-barked Betula

A significant pest affecting commonly planted Betula spp. is the birch leafminer (Fenusa pusilla Lepeletier), an insect that can be present in large populations in the landscape and can greatly reduce the vigor and ornamental value of these trees. Twenty-two interspecific crosses were performed between leafminer resistant and susceptible Betula species in an attempt to create the novel combination of ornamental white bark and significant leafminer resistance. Of the nine successful crosses, two produced resistant offspring. Progeny of the diploid × hexaploid cross B. turkestanica Litvin (2x) × B. alleghaniensis Britt. (6x) displayed a broad range of resistance levels, likely the result of segregating alleles contributed by the hexaploid parent. All crosses involving highly resistant individuals of B. costata Trautv. (2x) yielded leafminer susceptible progeny. These results suggest that the larval antibiosis demonstrated by B. alleghaniensis and B. costata is inherited as a recessive trait, and exhibits a gene dosage effect as evidenced by the B. turkestanica × B. alleghaniensis offspring. While most progeny of the B. populifolia Marsh (2x) × B. maximowicziana Regal (2x) cross were susceptible, a single resistant offspring, which was found to be triploid (3x), displayed a mechanism of resistance similar to that of a hypersensitive response. No strong intersectional barriers to hybridization were observed and all interploidy crosses were successful. The chromosome numbers of B. costata (2n = 2x = 28) and B. turkestanica (2n = 2x = 28) are reported here for the first time. The results of this study indicate that the potential exists for the development of insect resistant, ornamental white-barked birch clones through the implementation of a planned, systematic breeding program.

Evaluation of Dogwood and Birch Species and Cultivars for Resistance to Key Insect Pests and Diseases

Abstract Ten cultivars of dogwoods (Cornus spp.) were evaluated in multi-year trials for relative reisistance to the dogwood borer, Synanthedon scitula (Harris); cold injury; canker disease, Botryosphaeria dothidea; spot anthracnose, Elsinoe corni; and powdery mildew, Oidium sp., Microsphaera sp., and Phyllactinia sp. Similarly, eight cultivars of birch (Betula spp.) were evaluated for resistance to the birch leafminer, Fenusa pusilla (Lepeletier); Japanese beetle, Popillia japonica Newman; aphids, Hamamelistes spinosus Shimer; the bronze birch borer, Agrilus anxius Gory; and leaf-spot, Cryptocline betularum. All cultivars of C. florida, C. kousa and C. kousa x florida were susceptible to dogwood borer, although the C. florida cultivars were surviving better than the others. Cornus mas and C. kousa cultivars were relatively resistant to powdery mildew while C. florida x kousa hybrids and C. florida ‘Cherokee Brave’ were intermediately resistant. Betula platyphylla szechuanica ‘Purpurea’ was highly susceptible to the bronze birch borer, whereas B. nigra and B. n. ‘Heritage’ were the most susceptible birches to aphid damage. Betula jacquemontii was highly susceptible to Japanese beetle defoliation. Betula pendula, B. nigra, and B. n. ‘Heritage’ were most susceptible to defoliation by birch leaf spot. This study suggests that dogwood and birch cultivars vary in susceptibility to key insect pests and diseases. Planting relatively resistant cultivars may be useful in managing perennial pests in urban landscapes.

Establishment and spread of two introduced parasitoids (Ichneumonidae) of the birch leafminer, Fenusa pusilla (Lepeletier) (Tenthredinidae)

Lathrolestes nigricollis(Thomson) and Grypocentrus albipes Ruthe,Palearctic specialist parasitoids of thebirch-leafmining sawfly Fenusa pusilla(Lepeletier), were imported from central Europe andreleased at three locations in Edmonton, Alberta,Canada during 1994–1996. Parasitoids becameestablished at two locations, L. nigricollis atboth and G. albipes at one, and were recoveredfor 3–5 years after release. Lathrolestesnigricollis has dispersed throughout most ofEdmonton, and at least 13 km from release sites, butG. albipes has been recovered only 400–500 mfrom one release site. Five years after introductionat one site, percent parasitism by L.nigricollis was 78% and 84% for the first andsecond generations, respectively, and about 48% ofparasitoid eggs were encapsulated.

Mortality of Birch Leafmining Sawflies (Hymenoptera: Tenthredinidae): Impacts of Natural Enemies on Introduced Pests

Larvae of introduced birch leafmining sawflies in Alberta, Canada suffered light mortality from native generalist parasitoids of the family Eulophidae (Hymenoptera: Chalcidoidea). Eggs of Profenusa thomsoni (Konow) were attacked by 2 native species of Trichogramma (Chalcidoidea: Trichogrammatidae), and larvae of P. thomsoni were attacked by a more specialized native koinobiont parasitoid, Lathrolestes luteolator (Gravenhorst) (Ichneumonidae: Ctenopelmatinae). Spiders, beetles, hemipterans, thrips, ants, neuropterans, and flies preyed on Fenusa pusilla (Lepeletier) and P. thomsoni . Mortality levels differed between F. pusilla and P. thomsoni and tended to be higher in earlier instars, on urban trees, and during 1993. Experiments during 1993 revealed little predation of larval F. pusilla when population densities were uniformly high, but during the 1994 experiments, predators efficiently exploited branches having high densities of immature P. thomsoni within a matrix of low background P. thomsoni density.

Breeding for Leafminer Resistance within the Genus Betula

The birch leafminer (Fenusa pusilla) is an important insect pest of white-barked ornamental birches (Betula spp.). Although genetic resistance to birch leafminer exists within this genus, it has not been identified in the desirable white-barked species. Twenty-three interspecific crosses were performed in an attempt to combine ornamental white bark and leafminer resistance. The parental species and resulting hybrid populations were assayed for resistance. All assays utilized adult birch leafminers reared in our laboratory using a method we developed to provide a year-round supply of fresh leafminer adults. Previous studies viewed birch leafminer resistance as the unwillingness or inability of the female leafminer to oviposit eggs into the leaves of resistant Betula species. Our work has shown that female birch leafminers are unable to distinguish between suitable and nonsuitable host species. This work also has discovered two separate mechanisms of inherent resistance to the birch leafminer: leaf chemistry and a hypersensitive response. Two native species, B. alleghaniensis and B. lenta, kill the leafminer larvae shortly after hatching. Analyses suggest that a specific compound or class of compounds is responsible for leafminer mortality in these species and that this resistance is reduced in F1 hybrids that include a susceptible white-barked parent. The second resistance mechanism involves a hypersensitive response to the deposition of the leafminer egg and results in failure of the egg to hatch. Interestingly, this response is seen in one of our breeding lines (B. populifolia × B. maximowicziana), but has not been observed in either parental species. These hybrid progeny are currently in field test plots for further evaluation of leafminer resistance and ornamental characteristics.

ESTABLISHMENT, DISTRIBUTION, AND IMPACT IN SOUTHERN NEW ENGLAND OF LATHROLESTES NIGRICOLLIS (THOMPSON) (HYMENOPTERA: ICHNEUMONIDAE), AN INTRODUCED PARASITOID OF THE BIRCH LEAFMINER, FENUSA PUSILLA (LEPELETIER) (HYMENOPTERA: TENTHREDINIDAE)

AbstractLathrolestes nigricollis (Thompson) (Hymenoptera: Ichneumonidae) was released in New England against Fenusa pusilla (Lepeletier) in 1979–1980 and again in 1989–1990. By 1991, the parasitoid was widely established in southern New England. From 1979 to 1990 the commonness of leafminers at the original release site in the first generation declined from 50–54% of leaves mined to under 3%. Over 4 years at five sites, parasitism of larval birch leafminers increased between leafminer generations from 10.3% (G1) to 27.6% (G2) to 39.2% (G3). In Massachusetts, parasitism decreased (from 28 to 14%) with increasing distance from the original release site, while corresponding damage increased (from 6% of leaves mined to 33%). In areas local to the original release site (<4 km) parasitism has reduced damage from birch leafminer to inconsequential levels. Some sites in other parts of southern New England, particularly roadside sites, still have high levels of mined leaves in spite of the parasitoid’s presence in the general area.

STUDIES ON THE TRIBE FENUSINI OF CHINA (HYMENOPTERA: TENTHREDINIDAE)

Abstract The following new taxa from China are proposed in the Fenusini : Profenusa chrysichlorita sp. nov., Nefusa sinica sp. nov., Nefusa brevis sp. nov., Metallus sichuanensis sp. nov. , Metallus wangi sp. nov. , Metallus mai sp. nov., Nefusa sinica sp. nov. Nefusa bratis sp. nov., Metatlus sichuanensis sp. nov., Birmella discoidalisa sp. nov., Okutanius pekingensis sp. nov. All these genera except for Birmella with Fenusa pusilla (Lepel.), Fenella monilicornis Thomson and Profenusa hirashima Togashi are new records from China. New taxa are described and figured. Keys to genera and species of the tribe Fenusini from China are proposed.

Ant Predation on Two Species of Birch Leaf-Mining Sawflies

-The impact of ant predation on two species of leaf-mining sawflies, Fenusa pusilla, which uses newly unfolding birch leaves, and Profenusa thomsoni, which uses older birch leaves, is examined. Ants prey upon F. pusilla larvae while they are still in their mines more often than they do on P. thomsoni larvae. The upper and lower epidermal layers of the mines of P. thomsonz are thicker than those of F. pusilla. Ant predation of F. pusilla larvae is related negatively to the density of birch saplings in the immediate vicinity of a mined leaf. Additionally, the presence of a neighboring ant nest appears to create a spatial refuge for F. pusilla in the area of overlap between the two nests.

Systemic Activity of Neem Extract Against the Birch Leafminer

Pressurized micro-injection of neem seed extract into trunks of Betula papyrifera was evaluated for control of the birch leafminer, Fenusa pusilla (Lepeletier). Concentrations of 1.5 and 3.0% caused a significant decrease in foliar damage by birch leafminer when injected with the Mauget® microinjection system. Neem was as effective in reducing the number of adult leafminers reared from foliage of treated plants as Injecticide B® (bidrin) or Meta-Systox-R® . Phytotoxicity was not observed in any treatments. Micro-injections of neem may be an effective application technique as an integral part of IPM programs for controlling insect pests of trees.

Relationship Between Color Intensity of Leaf Supernatants from Resistant and Susceptible Birch Trees and Rate of Oviposition by the Birch Leafminer (Hymenoptera: Tenthredinidae)1

In no-choice laboratory tests, young leaves from trees of Betula davurica Pall. Fl. Ross., Betula maximowicziana Reg., Betula schmidtii Reg., and Betula costata Trautv. exhibited 95–100% reductions in oviposition by the birch leafminer Fenusa pusilla (Lepeletier) compared with leaves from Betula populifolia Marsh. Visible absorbance ratios (500 nm: 400 nm) of aqueous supernatants from leaves which exhibited high reductions in oviposition were 2.5- to 4-fold greater than ratios from leaves of B. populifolia. Results suggest these trees offer high resistance against birch leafminer damage and that absorbance characteristics of supernatants from young leaves can be used to detect high levels of resistance.

Use of Foliar-Applied Neem (Azadirachta indica A. Juss.) Seed Extract for the Control of the Birch Leafminer, Fenusa pusilla (Lepeletier) (Hymenoptera:Tenthredinidae)

The effect of 1.0% neenl (Azadirachta indica A. Juss.) seed extract applied as a foliar spray against the birch leafminer (Fenusa pusilla (Lepeletier)) was compared to sprays of water and Metasystox-R™. Sprays were applied against the season's first generation, at oviposition (V-3-86) or early instar (V-10-86). Sprayed foliage was harvested and weighed at late instar, and adults were reared. The extract caused significantly more leafminer mortality than did water, and caused as much mortality as Metasystox-R™. Observations suggested that the extract took longer to kill leafminer larvae than did Metasystox-R™ thereby allowing for more foliar damage. There were no differences in efficacy between times of extract application.

Introduction of Exotic Parasites for Biological Control of the Birch Leafminer (Hymenoptera: Tenthredinidae) in the Middle Atlantic States

Approximately 9,600 Lathrolestes nigricollis (Thomson), 2,600 Grypocentrus albipes Ruthe (Hymenoptera: Ichneumonidae), 50 Phanomeris sp. probably catenator Haliday (Hymenoptera: Braconidae), and 550 Chrysocharis nitetis (Walker) (Hymenoptera: Eulophidae) were released in the Middle Atlantic states from 1976 to 1982 in efforts to establish populations for biological control of the birch leafminer, Fenusa pusilla (Lepeletier). Releases of these parasites, all of European origin, were made in birch (Betula spp.) stands at 16 localities in Delaware, Maryland, New Jersey, and Pennsylvania. Two species, L. nigricollis and C. nitetis, are established in Pennsylvania.

RESISTANCE OF BETULA DAVURICA TO THE BIRCH LEAFMINER, FENUSA PUSILLA (HYMENOPTERA: TENTHREDINIDAE)

To our knowledge, reports of Betula spp. resistance against damage caused by the birch leafminer, Fenusa pusilla (Lepeletier), have not been published. Becker (1938), Friend (1933), and Johnson and Lyon (1976) stated that B. populifolia Marsh., B. papyrifera Marsh., and B. alba L. are the most commonly attacked species. Friend (1933) and Johnson and Lyon (1976) stated that B. lenta L., B. alleghaniensis Britt, and B. nigra L. have never been observed infested or are rarely fed upon.

INTRODUCTION DE PARASITES ICHNEUMONIDES POUR LA LUTTE BIOLOGIQUE CONTRE FENUSA PUSILLA (HYMENOPTERA: TENTHREDINIDAE) AU QUEBEC

RésuméEnviron 1,300 Lathrolestes nigricollis (Thompson) et 900 Grypocentrus albipes Ruthe (Hymenoptera: Ichneumonidae), ont été libérés au Québec, en 1974 et 1975, pour lutter contre la petite mineuse du bouleau, Fenusa pusilla (Lep.). Ces deux espèces de parasites européens ont été relâchées dans des peuplements de bouleau gris (Betula populifolla Marsh.) de quatre localités de la Vallée du St-Laurent. Les deux espèces ont engendré une progéniture mâle et femelle malgré l’absence d’accouplement bien caractérisé chez G. albipes. Trois générations de parasitoïdes, dont la première a hiverné, ont été enregistrées à la fin de l’été 1975. L’implantation de parasites de F. pusilla se présente jusqu’à date comme une réussite.

OBSERVATIONS ON MATING AND OVIPOSITION BEHAVIOUR OF PRIOPODA NIGRICOLLIS (HYMENOPTERA: ICHNEUMONIDAE), A PARASITE OF THE BIRCH LEAF-MINER, FENUSA PUSILLA (HYMENOPTERA: TENTHREDINIDAE)

AbstractThe premating period in the parasitoid Priopoda nigricollis (Thos.) is about 2 days, and females are receptive for up to 4 days, after which time the oviducts contain mature eggs. Copulation behaviour in specially built chambers, and oviposition pattern are described. The structure of the ovaries is illustrated. Host feeding by adult P. nigricollis was observed, but it is not a prerequisite for initial egg maturation. Hosts are located by random stabbing with the ovipositor into the mines of Fenusa pusilla (Lep.). Data on the age-specific fecundity of this parasite in laboratory experiments are given. The importance of liberating mated parasite populations is emphasized for successful biological control.

REVIEW OF NORTH AMERICANCHRYSOCHARIS(KRATOCHVILIANA) (EULOPHIDAE: CHALCIDOIDEA) NORTH OF MEXICO, ESPECIALLY SPECIES ATTACKING BIRCH CASEBEARER (LEPIDOPTERA: COLEOPHORIDAE) AND BIRCH LEAFMINER (HYMENOPTERA: TENTHREDINIDAE)

AbstractThis study provides information on the species ofChrysocharis(Kratochviliana) found in North America with special emphasis on the Canadian species attacking the birch casebearer,Coleophora serratella(L.) (=fuscedinellaZeller), and the birch leafminer,Fenusa pusilla(Lepeletier).The genusChrysocharisFörster in North America north of Mexico consists of two subgenera,KratochvilianaMaláč andChrysochariss. str. There are 15 Nearctic species ofKratochviliana, of which 10 species are described herein as new. These are:C. (Kratochviliana)robustan. sp.,C. (K.)incertan. sp.,C. (K.)stipitisn. sp.,C. (K.)hirsutiventrisn. sp.,C. (K.)walleyin. sp.,C. (K.)protolithocolletidisn. sp.,C. (K.)millerin. sp.,C. (K.)alutan. sp.,C. (K.)coptodiscaen. sp., andC. (K.)cuspidigastern. sp. Relationships and distribution of species-groups in North America and Europe are discussed. Keys to subgenera and species and host records are included.

MAJOR FACTORS IN SURVIVAL OF THE IMMATURE STAGES OF FENUSA PUSILLA IN SOUTHWESTERN QUEBEC

AbstractIntensive studies on the population dynamics of the birch leaf miner, Fenusa pusilla (Lepeletier), were carried out in two stands of blue birch at the Morgan Arboretum, Macdonald College, Que., from 1964 to 1966. Life tables for nine and two generations, respectively, showed that mortality of the immature stages was lower on 3- to 5-year-old trees than on 9-year-old trees. The analysis of successive age-interval survivals in relation to generation survival revealed that predation during the late larval stages was the key factor in generation survival of the insect on the younger trees. Desiccation of the leaf during the early larval stages along with predation were key factors on the older trees.

Systemic Insecticides Against the Spirea Aphid Birch Leaf Miner, and Nantucket Pine Tip Moth12345

Granular 10% disulfoton used at rates of 20 or 30 lb and aldicarb used at a rate of 20 lb active ingredient per acre gave excellent control of 3 generations of birch leaf miners, Fenusa pusilla (Lepeletier), on gray birch when applications were made either Feb. 29 or Mar. 27. Granular 10% phorate applied Apr. 4 at a rate of 30 lb active ingredient per acre and cultivated into the soil in 7-inch hands at both sides of the rows gave good control of the 2nd summer generation of Nantucket pine tip moths, Rhyacionia frustrana (Comstock), on Japanese black pine. No material tested was effective against the 1st summer generation. Granular 10% disulfoton applied May 3 at rates of 10 or 20 lb active ingredient per acre to rock cotoneaster in containers was effective against the spirea aphid, Aphis spiraecola Patch, until at least Aug. 11.

PARASITES AND PREDATORS OF THE BIRCH LEAF MINER, FENUSA PUSILLA (HYMENOPTERA: TENTHREDINIDAE), IN QUEBEC

AbstractTwenty-two species of insect parasites of Fenusa pusilla (Lepeletier) are listed. Fifteen of these species were reared in the present study from F. pusilla in Quebec, 1 on eggs and 14 on larvae; 4 of them act as both primary and secondary parasites. Of the 15, only 1 has previously been reported as a parasite of F. pusilla. Host–parasite relationship and the degree of parasitism are given for the 15 species reared in Quebec.Thirteen species of predators are listed. Of these, 9, three birds and six insects, were observed feeding on F. pusilla larvae during this study.