Eastern Hemlock Looper Research Articles

Lambdina fiscellaria (eastern hemlock looper)

Lambdina fiscellaria (eastern hemlock looper)

Cytology of Leidyana canadensis (Apicomplexa: Eugregarinida) in Lambdina fiscellaria fiscellaria Larvae (Lepidoptera: Geometridae)

The eugregarine Leidyana canadensis infects the larval gut of the eastern hemlock looper, Lambdina fiscellaria fiscellaria. Guts of infected larvae were chemically fixed, embedded in epoxy resin, and sectioned for light and electron microscopy to describe the cytology of L. canadensis and its pathology in the larval host. Oocysts of L. canadensis are ingested by larval hemlock looper. Trophozoites emerge from the oocysts, pass through the peritrophic membrane into the ectoperitrophic space, and attach to the epithelium of the midgut by means of an apical epimerite. The epimerite does not actually penetrate the affected epithelial cell; instead, it causes an invagination of the plasma membrane of the cell. The center of the epimerite contains membrane cisternae, and mitochondria line its periphery. Microtubules and mitochondria in the host cell cytoplasm surround the epimerite. At the light microscopic level, there appeared to be septa between the epimerite and the protomerite and between the protomerite and the deutomerite; however, in the electron microscope, no septa were evident. Only differences in the concentrations and nature of the inclusions in the cytoplasms of these three regions were apparent. The deutomerite contains a single nucleus in the central-posterior area. After an undetermined period, the epimerite detaches from the host gut epithelium and is withdrawn into the protomerite, and the trophozoites float freely in the ectoperitrophic space before differentiating into gamonts. Division of the single, large nucleus into numerous small nuclei appears to occur prior to syzygy. Gamonts pair and a cyst wall is laid down around them, forming a gametocyst. Oocysts are extruded from mature gametocysts, in chains, through sporoducts.

The relative performance of pheromone and light traps in monitoring the seasonal activity of both sexes of the eastern hemlock looper, Lambdina fiscellaria fiscellaria

AbstractThe seasonal flight activity of both sexes of the eastern hemlock looper, Lambdina fiscellaria fiscellaria Guenée (Lepidoptera: Geometridae) was studied during two consecutive years in Quebec and Newfoundland, using light (L), pheromone (P) and combined light and pheromone (LP) traps. Moth density significantly affected the performance of the different traps, with P traps being more effective at low than high density. However, P trap catches decreased just prior to the onset of female captures, probably as a result of competition between traps and virgin calling females. Nearly all females caught in L and LP traps were already mated and even the first females caught had laid at least half of their egg complement. In Quebec under warm nights, the pattern of male activity occurred at different times, with peak P catches being later in the scotophase than those of L traps, but overall similar numbers of males were caught in both traps. In contrast, under cool nights, males were caught early in the night in both P and L traps, suggesting a strong competition effect between traps, although more males were caught in P than L traps overall. In Newfoundland, the pattern of male captures in L and P traps was similar at both high and low temperatures, so competition between trap types would always be high. Under these conditions P traps were more effective than L traps. Irrespective of the region, year or temperature, significantly more males were captured in LP, with the effect of L and P being additive. In both regions, females responded similarly to L and LP traps with peak activity occurring early in the night. Captures of females were lower than those of males under cool temperatures, suggesting that the temperature threshold for flight is higher for females. The use of L and P traps simultaneously and/or in combination is discussed in relation to integrated pest management programs and ecological considerations.

SCREENING FOUR EXOTIC PARASITOIDS AS POTENTIAL CONTROLS FOR THE EASTERN HEMLOCK LOOPER,LAMBDINA FISCELLARIA FISCELLARIA(GUENÉE) (LEPIDOPTERA: GEOMETRIDAE)

AbstractAmong the 20 geometrid species recovered from annual surveys in coniferous forests in the Swiss Alps, three species,Epirrita autumnata(Borkhausen),Agriopis aurantiariaHübner, andPoecilopsis isabellaeHarrison, were identified as sources for parasitoids that might be suitable as candidates for introduction to Newfoundland to control the eastern hemlock looper,Lambdina fiscellaria fiscellaria(Guenée). Four univoltine Hymenoptera were identified as candidates:Dusona contumax(Forster) (Ichneumonidae) fromA.aurantiaria,Dusonasp. fromP.isabellae,Aleiodescf.gastritor(Thunberg) (Braconidae) fromE.autumnata, andAleiodes. sp. fromP.isabellae. The candidate parasitoids were confined with their native hosts in the laboratory and observations made to gather basic biological information and define protocols for screening.Small numbers of these parasitoids were shipped to Newfoundland and screened in the laboratory against hemlock looper larvae. Although attacks byD.contumax,Dusonasp., andA. cf.gastritorwere observed, parasitoid development did not occur. All parasitoid eggs recovered from the hemlock looper larvae attacked were encapsulated.Dusona contumax,Dusonasp. fromP.isabellae,A. cf.gastritor, andAleoidessp. fromP.isabellaeare not recommended for introduction against the eastern hemlock looper.

Leidyana canadensis N. Sp. (Apicomplexa: Eugregarinida) from Larval Eastern Hemlock Looper, Lambdina fiscellaria fiscellaria (Lepidoptera: Geometridae)

ABSTRACT. Leidyana canadensis n. sp. (Apicomplexa: Eugregarinida) is described from larvae of the eastern hemlock looper, Lambdina fiscellaria (Lepidoptera: Geometridae) collected near St. Stephen, Charlotte County, New Brunswick, Canada. Gamonts solitary, located between host ventricular peritrophic membrane and ventricular epithelium. Protomerite very broadly ellipsoid with transverse posterior margin; length 43.7 μm, width 42.7 μm; protomerite‐deutomerite septum strongly constricted. Deutomerite narrowly obovoid with anterior transverse margin; length 186.6 μm, width 58.7 μm; total length 227.1 μm. Nucleus spherical to broadly ellipsoid; length 26.3 μm, width 20.2 μm; placement abaxial in the posterior 2/3 of the deutomerite. Nucleus often obscured in late gamonts. Association late, caudofrontal, ephemeral and leading directly to syzygy. Gametocysts roughly spherical; diameter 216.7 μm; hyaline coat increasing diameter to 359.1 μm. Gametocysts mature and dehisce through six short spore tubes within 48 hours. Oocysts axially symmetric, dolioform in dorsal aspect, compressed in the plane perpendicular to the major axis, very uniform in size and shape; length along major axis 5.2 μm, terminal width 1.8 μm, medial width 3.8 μm; extruded in chains.

EFFICACY OF AERIAL APPLICATIONS OF BACILLUS THURINGIENSIS BERLINER AND TEBUFENOZIDE AGAINST THE EASTERN HEMLOCK LOOPER (LEPIDOPTERA: GEOMETRIDAE)

AbstractThe formulated product of the insect-molting hormone analog, tebufenozide (MIMIC 240LV), and two aqueous formulations of Bacillus thuringiensis subsp. kurstaki, ABG6387 and ABG6414, were aerially applied over prethinned commercial stands of balsam fir infested with the eastern hemlock looper. MIMIC® was applied once at the rate of 65.1 g active ingredient (ai) in 1.86 L/ha and twice at the rate of 33.4–35.4 g ai in 1.91–2.02 L/ha. The formulations of B. thuringiensis were applied twice at rates of 19.3–24.1 billion International Units (BIU) in 1.54–1.93 L/ha for ABG6387 and 33.2–36.0 BIU in 1.67–1.80 L/ha for ABG6414.Nine of the 10 plots treated with the single application of MIMIC showed reductions resulting from treatment, ranging from 3 to 93% within 9–11 days and 8 to 100% after 3 weeks. Plots treated twice with the lower dosage of MIMIC generally had larval population reductions of over 50% within 9–11 days of treatment and over 60% 3 weeks after treatment. For both treatments with MIMIC, plots with poor efficacy were clearly associated with low foliar deposition of the active ingredient. Overall, the results suggest that deposits of tebufenozide of less than 1.5 μg/g foliage do not give acceptable control of hemlock looper. Pupal population reductions resulting from treatment ranged from 8 to 99% for plots treated with the single application and 76 to 100% for plots treated twice at the half-dosage. Ground assessments of defoliation occurring after treatment ranged from 10 to 51% (year-old foliage) and 0 to 16% (current-year foliage) for the plots treated once, and 1 to 33% (year-old foliage) and 0 to 8% (current-year foliage) for the plots treated twice at the half-dosage. Thirty-five to 65% of year-old foliage and 15–39% of current-year foliage was defoliated in untreated check plots.Reductions resulting from treatment by ABG6387 ranged from 27 to 91% 10 days after the first application, from 73 to 99% 8 days after the second application, and from 90 to 100% for pupae. Plots treated with ABG6414 had larval population reductions from 76 to 93% 10 days after the first application and from 98 to 100% 7 days after the second application. No pupae were recovered in the plots treated with ABG6414. Defoliation assessed from ground level was less than 5% in the plots treated with ABG6387 and ABG6414 compared with defoliation of 10–29% of year-old foliage and 8–12% defoliation of current-year foliage in the check plots.

Characterization of Nuclear Polyhedrosis Viruses from Three Subspecies ofLambdina fiscellaria

The eastern hemlock looper (EHL),Lambdina fiscellaria fiscellaria,the western hemlock looper (WHL),L. fiscellaria lugubrosa,and the western oak looper (WOL),L. fiscellaria somniaria,are closely related insects that are pests in Canadian forests. We have used restriction endonuclease (REN) and Southern blot analyses to characterize DNA of nuclear polyhedrosis viruses (NPVs) isolated from each of the three subspecies ofL. fiscellaria.REN analysis of EHL-NPV, WHL-NPV, and WOL-NPV DNAs revealed that they have nonidentical REN-banding patterns. NPV DNA extracted from WOL larvae collected from Douglas fir trees had a different REN pattern than NPV DNA extracted from WOL larvae collected from Garry oak trees. Hybridization of radiolabeled EHL-NPV genomic DNA revealed that the EHL- and WHL-NPVs share considerable DNA sequence similarity, as radiolabeled EHL-NPV DNA hybridized strongly with all WHL-NPV DNA bands. The EHL-NPV polyhedrin gene hybridized strongly with WHL-NPV DNA, but the hybridization patterns of the two NPVs were different. Very weak hybridization was detected between the EHL-NPV polyhedrin gene and DNAs of the two WOL-NPVs. Nucleotide sequence analysis revealed that the polyhedrin genes of EHL-NPV and WHL-NPV differ in sequence by only eight nucleotide substitutions (five third position and three second position changes, resulting in four amino acid substitutions). Phlyogeneitc analysis using the polyhedrin genes of EHL-NPV and WHL-NPV indicate that these two viruses cluster with the Group II NPVs as described by Zanotto, Kessing, and Maruniak (1993,J. Invertebr. Pathol.62,147).

Effects of Relative Humidity and Temperature on Entomophaga aulicae Conidium Discharge from Infected Eastern Hemlock Looper Larvae and Subsequent Conidium Development

The effects of relative humidity (RH) and temperature on conidium discharge from Entomophaga aulicae-infected eastern hemlock looper ( Lambdina fiscellaria fiscellaria) larvae and subsequent conidium development were examined. Fourth-instar larvae were injected with 460 fungal protoplasts (=LC 50 dosage). At 20°C, RH (66, 86, and 93%) had no effect on the level of larval mortality. At 93% RH, more primary, secondary, tertiary, quaternary, and quinary conidia were produced over a 2-day period than at either 66 or 86% RH. At 66% RH, only primary conidia were produced and only on 1 day. At 20°C, the highest level of germ tube formation by primary conidia occurred at 86% RH, whereas the highest level of secondary conidium production and the longest germ tubes occurred at 93% RH. Sixty-six percent RH was unsuitable for either germ tube or secondary conidium production. Injected larvae were initially incubated at 4, 10, 15, 20, 25, and 30°C. The highest level of larval mortality occurred at 20°C (93% RH). The time to host death decreased with increasing temperature. The number of degree-days to host death at 93% RH was 75 to 90 at 15°C, 80 to 100 at 20°C, and 75 to 100 at 25°C. At 20°C and 93% RH, the fungus produced an average of 1.2 × 10 5 primary conidia per fourth-instar larva.

Object-oriented modeling and GIS integration in a decision support system for the management of eastern hemlock looper in Newfoundland

Abstract Recently available system design tools were used to explore the re-engineering of pest management models and the computer system frameworks used to deliver these models in order to improve model expansion and to apply them to new problems. These models and frameworks were integrated with software tools to form decision support systems (DSS) for operational use by managers in the field. Modeling of insect management could then be supported by these systems. In a test case, a DSS that modeled the predicted impact of the eastern hemlock looper Lambdina fiscellaria fiscellaria (Gn.) lacked expressiveness and was difficult to modify and apply to new situations. As well, the architecture of the DSS did not promote reusability and extensibility of the code. To help solve these problems, the insect application was redesigned in an object-oriented (OO) structure. Analysis and design was supported by the OMTool software. The design was ther prototyped in the ProKappa system development environment to determine the effectiveness of the design. The OO paradigm provided a new approach to rebuild the models based on natural, hence more stable, abstractions rather than artificial ones contrived to suit computer processing, which is the situation normally encountered with traditional, procedural styles of programming. The flexible structure of the design enabled easier construction of new applications in the pest management domain.

Sex pheromone components of the spring hemlock looper,Lambdina athasaria (Walker) (Lepidoptera: Geometridae)

Two methylated hydrocarbons, 7-methylheptadecane (7) and 7,11-dimethylheptadecane (7,11), are female sex pheromone components of the spring hemlock looper (SHL),Lambdina athasaria (Walker). Compounds extracted from female pheromone glands were identified by coupled gas chromatographic-electroantennographic detection (GC-EAD) and coupled GC-mass spectrometry (GC-MS) in selected ion monitoring mode. In field trapping experiments, (7) and (7,11) by themselves were behaviorally inactive, but in combination attracted numerous male moths. (5,11)-Dimethylheptadecane (5,11) was detected in female SHL pheromone gland extracts, but did not enhance attraction to the binary blend of (7) and (7,11). The sex pheromone of SHL is related to that of congeneric eastern hemlock looper (EHL),Lambdina fiscellaria fiscellaria (Guen.) [(5,11) and 2,5-dimethylheptadecane (2,5)] and western hemlock looper (WHL),L.f. lugubrosa (Hulst) [(5,11), (2,5) and (7)]. Specificity of the pheromonal blend, spatial separation of coseasonal EHL and WHL, and temporal separation of sympatric EHL and SHL contribute to reproductive isolation.

Chirality of 5,11-dimethylheptadecane, the major sex pheromone component of the hemlock looper,Lambdina fiscellaria (Lepidoptera: Geometridae)

Of the four possible stereoisomers of 5,11-dimethylheptadecane, the major sex pheromone component of the eastern hemlock looper (EHL),Lambdina fiscellaria fiscellaria Guen., and the western hemlock looper (WHL),Lambdina fiscellaria lugubrosa Hulst, (5R,11S)-5,11-dimethylheptadecane was the only stereoisomer eliciting electrophysiological responses by male EHL and WHL antennae. In field bioassays with EHL and WHL populations, traps baited with (5R,11S)-5, 11-dimethylheptadecane caught as many males as did traps baited with all four stereoisomers combined or a synthetic mixture of 5,11-dimethylheptadecanes. Catches in traps baited with the other three stereoisomers did not significantly differ from those in the unbaited control traps. We conclude that male antennae lack chemoreceptors for the other three stereoisomers of 5,11-dimethylheptadecane and hypothesize that only (5R,115)-5,11-dimethylheptadecane is produced by female EHLs and WHLs.

An inexpensive medium for mass fermentation production of Entomophaga aulicae hyphal bodies competent to form conidia

A mass fermentation medium for growth and morphogenesis of the entomopathogenic fungus Entomophaga aulicae was developed. This fungus is a major pathogen of larval eastern hemlock looper and spruce budworm. The medium consists of a basal medium plus 0.8% tryptic soy broth and 0.4% calcium caseinate. This medium is a major breakthrough in that (i) the E. aulicae developmental sequence from protoplast inoculum to hyphal bodies competent to form conidia can be carried out in a single medium without adjustment, (ii) by examining the fermentation product it can be determined if conidia can be produced prior to engaging in costly field spraying, (iii) this medium supports the growth of E. aulicae isolates from different geographical areas, (iv) the medium is relatively inexpensive, (v) the hyphal bodies are easily separated from the spent growth medium, and (vi) the hyphal body yield is high.Key words: Entomophaga aulicae, mass fermentation medium, hyphal bodies, conidia, insect biocontrol.

Sex pheromone of the western hemlock looper,Lambdina fiscellaria lugubrosa (Hulst) (Lepidoptera: Geometridae)

The sex pheromone of the western hemlock looper (WHL),Lambdina fiscellaria lugubrosa (Hulst), comprises three methylated hydrocarbons: 5,11-dimethylheptadecane (5,11), 2,5-dimethylheptadecane (2,5), and 7-methylheptadecane (7). Compounds extracted from female pheromone glands were identified by coupled gas chromatographic-electroantennographic (GC-EAD) analysis and coupled GC-mass spectroscopy in selected ion monitoring mode. In trapping experiments, (5,11) alone attracted male moths, but addition of either (7) or (2,5) significantly enhanced attraction. (5,11) combined with both (7) and (2,5) was significantly most attractive. (5,11) and (2,5) are also sex pheromone components of the eastern hemlock looper (EHL),Lambdina fiscellaria fiscellaria (Guen.). Although (7) is produced by the EHL, it is a pheromone component only in the WHL. It constitutes the first behaviorally active monomethyl-branched hydrocarbon to be found in a geometrid and is a novel lepidopteran sex pheromone component. The different 2- versus 3-component sex pheromone supports taxonomic division of EHL and WHL.

Comparative toxicity of the HD-1 and NRD-12 strains of Bacillus thuringiensis subsp. kurstaki to defoliating forest Lepidoptera

Insecticidal activities of sporulated cultures of the HD-1 and NRD-12 strains of Bacillus thuringiensis subsp. kurstaki were compared against four species of defoliating forest lepidopterans in diet-incorporation assays. There was no difference in LC 50 between the two strains to larvae of spruce budworm ( Choristoneura fumiferana), gypsy moth ( Lymantria dispar), eastern hemlock looper ( Lambdina fiscellaria fiscellaria), and whitemarked tussock moth ( Orgyia leucostigma), whether expressed as total alkaline soluble protein, activated toxin protein, or International Units as determined by bioassay against Trichoplusia ni. Both strains were consistently more toxic than HD-1-S-1980 when compared on the basis of alkali-soluble protein, but not on the basis of activated toxin or International Units. Hybridization of genomic DNA after restriction with HindIII revealed the presence of all three cryIA toxin genes in each of the isolates used in this study, including HD-1-S-1980, which was previously reported to have lost the cryIA(b) gene.

A sequential decision plan for the management of the eastern hemlock looper, Lambdinafiscellariafiscellaria (Lepidoptera: Geometridae), in Newfoundland

A sequential decision plan based on Wald's sequential probability ratio test for the negative binomial distribution was derived for eastern hemlock looper (Lambdinafiscellariafiscellaria (Guen.)) egg populations in Newfoundland. An average sample number of not more than six midcrown branches was feasible, and both α and β error rates were defined. Monte Carlo simulation of operating characteristic and average sample number values for static and dynamic K of the negative binomial showed that Wald's sequential probability ratio test was acceptable. More eggs were found on midcrown balsam fir (Abiesbalsamea (L.) Mill.) branches than on other sampling substrates, such as ground mosses (mainly comprising Hylocomiumsplendens (Hedw.) B.S.G., Pleuroziumschreberi (Brid.) Mitt., and Ptiliumcrista-castrensis (Hedw.) De Not.), loose bark from paper birch (Betulapapyrifera Marsh.), and crown lichens (primarily Usnealongissima Ach.).

Development of Entomophaga aulicae protoplasts in synthetic eastern hemlock looper hemolymph

The protoplast stages of Entomophaga aulicae grew in a medium based on the amino acid and amine composition of the hemolymph of the eastern hemlock looper, Lambdina fiscellaria fiscellaria. The optimum temperature and pH ranges for spindle-shaped protoplast growth were 15 to 25 °C and 5.5 to 6.5, respectively. Spindle-shaped protoplast development progressed asynchronously through the formation of mesoprotoplasts, elliptical mesoprotoplasts, and rod-shaped and spherical hyphal bodies. The production of these stages was not influenced by either medium pH or osmolality. Conidia were formed on conidiophores arising from spherical hyphal bodies near the surface of the culture medium. Changes in amino acid and amine levels during growth were correlated with the stage of fungal development. The major amino acids utilized during development included L-glutamine, L-asparagine, L-proline, L-leucine, L-isoleucine, L-tyrosine, and the amine O-phosphoethanolamine.Key words: Entomophaga aulicae, Lambdina fiscellaria fiscellaria, protoplasts, hemolymph, ninhydrin-positive compounds.

EFFICACY OF OIL-BASED FORMULATIONS OF BACILLUS THURINGIENSIS BERLINER VAR. KURSTAKI AGAINST THE HEMLOCK LOOPER, LAMBDINA FISCELLARIA FISCELLARIA (GUEN.) (LEPIDOPTERA: GEOMETRIDAE)

AbstractOil-based formulations of Bacillus thuringiensis Berliner var. kurstaki, Dipel 132, Dipel 176, and Dipel 264, were aerially applied at rates of 1.18–2.36 L/ha over five 30-ha plots in a balsam fir, Abies balsamea (L.) Mill., forest in efficacy tests against the eastern hemlock looper, Lambdina fiscellaria fiscellaria (Guen.), in Newfoundland. Double applications of 30 Billion International Units (BIU) per hectare of each formulation and single applications of 40 BIU per hectare of Dipel 176 and Dipel 264 were tested. Larval population reductions of more than 95% and no defoliation of old or new foliage were observed in the plots receiving double applications and in the plot treated with a single application of Dipel 264. Larval numbers were reduced by 85% and defoliation was 4% in the plot treated once with Dipel 176.These treatments were applied against low to moderate larval populations, and their success was attributed to excellent spray coverage and early application when 50% or more of the larvae were still in their first instar.

Comparative Physiology of Two Isolates ofEntomophthora Egressa

Isolate 458 of Entomophthora egressa from larvae of the eastern hemlock looper and isolate 521 from larvae of the spruce budworm differed in colony morphology on coagulated egg yolk medium, protoplast growth rate in modified Grace's medium, regeneration sequence, effect on growth medium [pH, osmolality, individual and total ninhydrin-positive compound (NPC) levels, total protein and glucose concentration], rate of glucose uptake, protein synthesis, degree of amino acid utilization and growth response to CO2. The major NPC utilized included t.-aspartic acid, iL-glutamic acid, L-lysine, L-histidine, L-tyrosine, L-leucine, L-valine, I-glutamine, glycine, DL-serine and /3-alanine. The major endogenous protoplast NPC were L-glutamic acid, L.histidine, L-alanine, DLt.-serine and glycine with moderate levels of L.-aspartic acid, t-arginine, i.-proline, t.-glutamine, tL-asparagine and /f-alanine. As a result of the observed developmental and physiological differences, we conclude that isolates 458 and 521 are representatives of two distinct physiological races of E. egressa.

Response of eastern hemlock looper hemocytes to selected stages of Entomophthora egressa and other foreign particles

Indirect evidence for the natural existence of the free-protoplast stage of the fungus Entomophthora egressa in the eastern hemlock looper, Lambdina fiscellaria fiscellaria, is presented. The protoplasts were viable after 72 hr postinjection and subsequent development in the host produced conidia characteristic of E. egressa. The hemocytes studied (plasmatocytes, granular cells, and spherule cells) did not adhere to the protoplasts either in vivo or in vitro. Cells of Escherichia coli and sporangiospores of Absidia repens adhered to the granular cells in vitro. The granular cells adhered to the hyphae of Rhizopus nigricans in vitro. The spherule cells strongly adhered to the hyphae and hyphal bodies of E. egressa in vitro. The protoplasts, hyphae, and conidia of E. egressa and the hemocytes of L. fiscellaria fiscellaria adhered to positively charged DEAE-Sephadex beads and not to negatively charged CM-Sephadex beads. Aspects of active and passive strategies for protoplast evasion of host hemocytes are discussed with some emphasis on hemocyte-protoplast electrostatic repulsion and active secretion of hemocyte inhibitors by the protoplasts.

NINHYDRIN-POSITIVE SUBSTANCE ANALYSIS OF LARVAL HEMOLYMPH OF THE EASTERN HEMLOCK LOOPER, LAMBDINA FISCELLARIA FISCELLARIA (LEPIDOPTERA: GEOMETRIDAE) AND GROWTH OF ENTOMOPHTHORA EGRESSA PROTOPLASTS

AbstractA ninhydrin-positive substance analysis of fourth instar larval hemolymph of the eastern hemlock looper, Lambdina fiscellaria fiscellaria (Guenée), was conducted. Two separate larval populations were reared on a defined diet during the early stages and later on fresh, young balsam fir foliage. The results indicated the presence of at least 38 compounds. L-glutamine and(or) L-asparagine, L-histidine, and L-lysine occurred at high concentrations (> 5000 nM/ml). Ammonia, L-arginine, L-threonine, L-serine, L-glutamic acid, glycine, L-alanine, L-valine, L-isoleucine, L-leucine, L-tyrosine, and L-phenylalanine occurred at intermediate levels (1000–5000 nM/ml). The current report of the presence of L-1-methylhistidine and L-3-methylhistidine is the second report of any methylated derivative of histidine in insect hemolymph. The results of the analytical study were used to modify the composition of Grace’s insect tissue culture medium which had previously been found to support growth of protoplasts of the looper pathogen Entomophthora egressa MacLeod and Tyrrell. Fungal growth indicated a shorter generation time (4.7 h) on the medium modified to more closely approximate the looper hemolymph as compared with the generation time (6.2 h) on Grace’s medium.