Assessing Gypsy Moth (Lepidoptera: Lymantriidae) Larval Mortality Caused by the Parasitoid Cotesia melanoscela (Hymenoptera: Braconidae): Host Age Effects

1990 ◽  
Vol 19 (3) ◽  
pp. 771-775 ◽  
Author(s):  
Kevin W. Thorpe ◽  
M. J. Raupp ◽  
T. M. Odell
Keyword(s):  
Gypsy Moth ◽  
Larval Mortality ◽  
Age Effects ◽  
Host Age ◽  
Cotesia Melanoscela

scholarly journals Effectiveness of Diflubenzuron and Bacillus thuringiensis Against Gypsy Moth Populations

1997 ◽  
Vol 14 (3) ◽  
pp. 135-140 ◽  
Author(s):  
Kevin W. Thorpe ◽  
Richard L. Ridgway ◽  
Ralph E. Webb
Keyword(s):  
Bacillus Thuringiensis ◽  
Population Density ◽  
Gypsy Moth ◽  
Mass Density ◽  
Larval Mortality ◽  
Larval Density ◽  
Egg Mass ◽  
Percent Reduction ◽  
Moth Population ◽  
Oak Trees

Abstract Aerial applications of Bacillus thuringiensis Berliner subsp. kurstaki (74.1 billion international units/ha per application; single and double applications), diflubenzuron [69 g (ai)/ha], and no treatment were evaluated. Treatment effects were estimated from frass collections, defoliation, counts of pupae under burlap, and egg-mass counts. Estimates of larval density in the canopy 20 days after treatment ranged from 318.3 to 55.5 larvae per m² in the control- and diflubenzuron-treated plots, respectively. Larval density was reduced in all treatments, and was lowest in the plots treated with diflubenzuron and two applications of B. thuringiensis. Population density rapidly declined in the control plots, and by June 20, when larvae were predominantly in the fifth and sixth instars, no significant differences in larval density were detected among the treatments. Significantly less defoliation occurred to oak trees in the treated plots, but no differences were detected among the spray treatments. Counts of pupae under burlap, postseason egg-mass counts, and percent reduction in egg-mass density did not differ significantly among treatments or versus controls. These results suggest that diflubenzuron and double B. thuringiensis treatments caused higher levels of larval mortality than occurred with a single B. thuringiensis application, but that with a naturally declining gypsy moth population the final levels of damage were the same under all treatments. North. J. Appl. 14(3):135-140.

The fisheries management implications of maternal-age-dependent larval survival

2006 ◽  
Vol 63 (10) ◽  
pp. 2249-2258 ◽  
Author(s):  
Michael R O'Farrell ◽  
Louis W Botsford
Keyword(s):  
Mortality Rate ◽  
Fisheries Management ◽  
Maternal Age ◽  
Egg Production ◽  
Larval Mortality ◽  
Reproductive Potential ◽  
Larval Survival ◽  
Age Effects ◽  
Fishing Mortality ◽  
Black Rockfish

A common goal of conventional fisheries management is to maintain fishing mortality at a rate that ensures an adequate level of lifetime egg production (LEP) for population sustainability. However, larvae from young spawners can experience higher mortality rates than larvae of older spawners, reducing the effect of egg production by young females (hereafter, maternal age effects). This reduction leads to an error in LEP that can be accounted for by reducing the fishing mortality rate, but raises the question of the magnitude of these errors if they are present but not accounted for. Calculations using parameters from a typical long-lived fish demonstrated that maternal age effects resulted in large errors in estimates of lifetime reproduction when there was a large contrast in the larval mortality rate extending over the reproductive life span. Errors were small when maternal age effects reduced the reproductive potential of only the very youngest spawners, at ages when a small fraction of females are mature. A specific example using the empirically derived maternal age effect for black rockfish (Sebastes melanops) indicated that errors in traditional management would be small for this species.

Temperature and host age effects on the life history of Tamarixia radiata, a dominant parasitoid of citrus psyllid Diaphorina citri

2018 ◽  
Vol 114 ◽  
pp. 32-38 ◽  
Author(s):  
Yi-Han Li ◽  
Ya-Ting Zhou ◽  
Chang-Fei Guo ◽  
Da Ou ◽  
Jawwad A. Qureshi ◽  
...  
Keyword(s):  
Life History ◽  
Age Effects ◽  
Host Age ◽  
Diaphorina Citri ◽  
History Of

Host Age Effects on Ovipositional and Developmental Biology of Baryscapus chrysopae (Hymenoptera: Eulophidae), a Parasitoid of Chrysopid Larvae

1995 ◽  
Vol 30 (2) ◽  
pp. 287-293
Author(s):  
John R. Ruberson ◽  
Timothy J. Kring
Keyword(s):  
Developmental Biology ◽  
Sex Ratio ◽  
Developmental Time ◽  
Age Effects ◽  
Host Age ◽  
Larval Stages ◽  
Chrysoperla Rufilabris ◽  
Host Stage ◽  
Gregarious Parasitoid

The parasitoid, Baryscapus (=Tetrastichus) chrysopae (Crawford), is a widely-distributed gregarious parasitoid of chrysopid larvae. The ovipositional and developmental biology of this parasitoid in relation to the stage of its host, Chrysoperla rufilabris (Burmeister), was examined. Female B. chrysopae attacked all larval stages of the host tested (instars 1 to 3), and paralyzed all hosts soon after mounting and stinging. During the host's paralysis, females oviposited in and fed on hosts. The time females spent on hosts was directly related to host stage. All hosts recovered from paralysis. Parasitoid developmental time was inversely related to host stage and ranged from 27.5 d in 1-d-old hosts to 20.5 d in 10-d-old hosts. Most development of parasitoid larvae appears to occur after the host has spun its pupal cocoon. The number of parasitoids produced per host was unrelated to host stage, ranging from 10.5 (in 1-d-old hosts) to 14.2 (in 7-d-old hosts) parasitoids per host. The sex ratio was skewed toward females (81.6% pooled across host stages) and was unrelated to host stage. The developmental biology of B. chrysopae appears to be well synchronized with that of its host.

Comparison of Aerially-Applied Gypchek Strains Against Gypsy Moth (Lepidoptera: Lymantriidae) in the Presence of an Entomophaga maimaiga Epizootic

2005 ◽  
Vol 40 (4) ◽  
pp. 446-460 ◽  
Author(s):  
R. E. Webb ◽  
G. B. White ◽  
J. D. Podgwaite ◽  
V. D'Amico ◽  
J. Slavicek ◽  
...  
Keyword(s):  
Gypsy Moth ◽  
Larval Mortality ◽  
Larval Population ◽  
Usda Forest Service ◽  
Entomophaga Maimaiga ◽  
Wave Effects ◽  
Late Instar ◽  
Fungal Entomopathogen ◽  
Occlusion Bodies ◽  
Second Wave

The standard strain (LDP-226) of Gypchek®, a nucleopolyhedrovirus product registered by the USDA Forest Service against the gypsy moth, Lymantria dispar (L.), was compared against a strain, LdMNPV-203NL (NL = nonliquefying), that was developed for production in cell culture. Both strains were applied by air to U.S. government property in Prince Georges Co., MD, in early May 2003 at the rate of 1 × 1012 occlusion bodies per ha. The two goals of the study were (1) to compare the first and second wave effects of the two strains against gypsy moth populations; and (2) to delineate the combined effects of the applied virus and the expected epizootic of the gypsy moth specialist fungal entomopathogen Entomophaga maimaiga Humber, Shimazu, and Soper. Heavy rainfall in May and June preceded a massive epizootic of E. maimaiga, whose effects did not mask the first wave of viral mortality. When the effect of application sequence was considered, it was concluded that the two strains were equivalent in their first-wave impacts. High fungal-induced mid and late-season gypsy moth larval mortality suppressed the second wave of virus at all evaluation sites. There were no obvious differences in the second waves engendered by the two LdNPV strains in the greatly reduced late-instar larval population.

DIFFERENCES IN THE UTILIZATION OF TREE SPECIES AS LARVAL HOSTS AND PUPATION SITES BY THE GYPSY MOTH, LYMANTRIA DISPAR (LEPIDOPTERA: LYMANTRIIDAE)

1984 ◽  
Vol 116 (5) ◽  
pp. 685-690 ◽  
Author(s):  
Yves Mauffette ◽  
Martin J. Lechowicz
Keyword(s):  
Gypsy Moth ◽  
Host Species ◽  
Quercus Rubra ◽  
Larval Mortality ◽  
Coniferous Species ◽  
Juglans Cinerea ◽  
Ostrya Virginiana ◽  
Carya Ovata ◽  
Host Trees ◽  
Late Instar

AbstractIn the summer of 1980, gypsy moth populations were monitored in 13 sparsely infested forests in southwestern Quebec; counts of living and dead larvae and pupae were made on 1,870 trees representing 28 deciduous and one coniferous species. Contrary to our null expectations, the proportionate numbers of pupae compared with larvae on the various host species were not equal. Hosts more preferred by larvae were less preferred by pupae, and vice versa. For example, pupae were disproportionately abundant on host species like Acer pensylvanicum L., Carya ovata (Mill.) K. Koch, and Juglans cinerea L. which are not generally favored larval hosts. Conversely, favored larval hosts like Quercus rubra L. and Ostrya virginiana (Mill.) K. Koch carried lower numbers of pupae than expected from the numbers of larvae feeding on them. Such differential utilization of host trees by larvae versus pupae, which can arise either from host-dependent differences in larval mortality or from late instar migration between hosts, may contribute to maintaining the broad polyphagy of gypsy moth larvae.

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