An Assessment of Gypsy Moth Eradication Attempts in Michigan (Lepidoptera: Lymantriidae)

Michigan\u27s infestation of gypsy moth, Lymantria dispar, extends over 600,000 acres, First discovered in Michigan in the 19505, gypsy moth was reportedly eradicated through the use of DDT then reintroduced in the 1970s, Substantial circumstantial biological evidence, however, points to the probability that gypsy moth has resided continuously in Michigan for over 30 years, Environmental factors may be largely responsible for containing Michigan\u27s gypsy moth popUlations

Gypsy Moth (Lepidoptera: Lymantriidae): History of Eradication Efforts in Michigan, 1954-1981

Gypsy moth, Lymantria dispar, was first discovered in Michigan in 1954, Aerial spraying operations were conducted to eradicate gypsy moth infestations with synthetic insecticides (DDT, carbaryl, and diflubenzuron)

Effects of Hybrid Poplar (Salicaceae) Clone and Phenology on Gypsy Moth (Lepidoptera: Lymantriidae) Performance in Wisconsin

Gypsy moth (Lymantria dispar) developmental interactions with two hybrid Populus species clones were studied in laboratory trials. Significant differences in larval performance were found between clones and within the same clone at different phenological states. No larvae were able to complete development on clone NM6. All gypsy moth larvae feeding on clone NC5271 survived when leafflush was synchronized with gypsy moth eclosion in early May. However, neonates feeding on NC5271 foliage in July experienced in- creased mortality. Weights of surviving gypsy moth larvae feeding on NC5271 foliage in May versus July were not significantly different

Susceptibility of the Endangered Karner Blue Butterfly (Lepidoptera: Lycaenidae) to \u3ci\u3eBacillus Thuringiensis\u3c/i\u3e Var. \u3ci\u3eKurstaki\u3c/i\u3e Used for Gypsy Moth Suppression in Michigan

We investigated the phenological and physiological susceptibility of the endangered Karner blue butterfly (Lycaeides melissa samuelis) to Bacillus thuringiensis var. kurstaki (Bt), a product widely used for gypsy moth (Lymantria dispar) suppression in Michigan and other infested states. We monitored phenology of the bivoltine Karner blue in two regions of Michigan from 1993 to 1995 to determine if larval stages overlapped temporally with the period of Bt application for gypsy moth suppression. Karner blue larvae of the spring generation were found during the period that Bt was applied in nearby areas in 1993 only. However, spring-generation adults or newly laid eggs were observed up to 11 days before applications in 1994 and 1995. Since Karner blue eggs develop within one week, summer-generation larvae were most likely present during or shortly after 1994 and 1995 Bt application periods. These larvae would have been at risk, assuming Bt persistence of 4 to 6 days. Physiological susceptibility of Karner blue larvae to Bt was determined in a laboratory bioassay. Larvae were reared on wild lupine (Lupinus perennis) foliage that was untreated, or sprayed with Bt formulations at rates of 30-37 or 90 BIU/ha. A similar bioassay with second instar gypsy moth larvae on similarly treated white oak (Quercus alba) foliage was conducted concurrently. Karner blue survival was 100%, 27% and 14% on control, low and high Bt treatments, respectively. Early and late Karner blue instars were equally susceptible to Bt. Survival of gypsy moth was 80%, 33% and 5% on control, low and high Bt treatments, respectively, and did not differ significantly from Karner blue survival. We conclude that Karner blue is both phenologically and physiologically susceptible to Bt used for gypsy moth suppression, although the larval generation at risk and extent of phenological overlap may vary from year to year

Enhancement of biological control agents for use against forest insect pests and diseases through biotechnology

Research and development efforts in our research group are focused on the generation of more efficacious biological control agents through the techniques of biotechnology for use against forest insect pests and diseases. Effective biological controls for the gypsy moth and for tree fungal wilt pathogens are under development. The successful use of Gypchek, a formulation of the Lymantria dispar nuclear polyhedrosis virus (LdNPV), in gypsy moth control programs has generated considerable interest in that agent. As a consequence of its specificity, LdPNV has negligible adverse ecological impacts compared to most gypsy moth control agents. However, LdNPV is not competitive with other control agents in terms of cost and efficacy. We are investigating several parameters of LdNPV replication and polyhedra production in order to enhance viral potency and efficacy thus mitigating the current disadvantages of LdNPV for gypsy moth control, and have identified LdNPV variants that will facilitate these efforts. Tree endophytic bacteria that synthesize antifungal compounds were identified and an antibiotic compound from one of these bacteria was characterized. The feasibility of developing tree endophytes as biological control agents for tree vascular fungal pathogens is being investigated

Mating Success of Gypsy Moth (Lepidoptera: Lymantriidae) Females in Southern Wisconsin

Mating success of laboratory-reared gypsy moth Lymantria dispar (L.) females exposed for 24 hr on tree boles and its relationship to male moth counts in pheromone-baited traps was studied in southern Wisconsin. The relationship between mating probability of gypsy moth females and male moth counts in traps corresponded to an exponential model that can be used for predicting mating probabilities in sparse isolated populations. Relative attractiveness of females compared with traps was 0.23, which is similar to earlier estimated relative attractiveness of females in Virginia. The mortality of females from predation, however, was found to be significantly lower in Wisconsin than in Virginia, which may contribute to a larger degree of mating success. Increased long-distance dispersal of males could also contribute to the increased mating success of females. The higher rate of spread of gypsy moth populations in Wisconsin compared with other areas may be due to the increased mating success caused by the lower female mortality and higher long-distance dispersal of males

Alternatives to the Gypsy Moth Eradication Program in Michigan

Responding to questions of what the gypsy moth, Porthetria dispar, would do in Michigan forests, a computer simulation model was constructed. The model consisted of three subunits: a submodel of gypsy moth population dynamics, a submodel of forest growth and a submodel of tree defoliation and mortality. Several different policies were simulated for an 80 year period. The eradication policy now employed in Michigan failed due to survival of small portions of the population. Allowing the gypsy moth to become established in Michigan forests and then responding by spraying when defoliation is visible provided a policy with the least economic and environmental cost

Indirect effects between deer, mice, and the gypsy moth in a forest community

White-tailed deer are ecosystem engineers that dramatically alter forest understory vegetation. Consequently, deer can impact many species in a forest through both direct and indirect effects. One species that deer may indirectly affect is the gypsy moth, whose pupae are preyed upon by the white-footed mouse. Through alterations to understory habitat of mice, deer may reduce mouse predation on gypsy moth pupae. In this study, I tested for indirect effects of deer on the gypsy moth by comparing mouse abundance, vegetation properties, and predation on pupae inside, and outside, of long-term deer exclosures. Overall, I did not find evidence for indirect effects of deer on the gypsy moth. There was little effect of the exclosures on mouse abundance, predation rates, and habitat measures. High mouse abundances, which likely resulted from a large acorn mast the previous year, may be obscuring indirect effects that would be detected at lower mouse abundances

Development of gypsy moth (Lymantria dispar L) on the foliage of Quercus cerris L., Q. Petraea (matt) Liebl. and Q. Robur L. in the controlled conditions

The development of Gypsy moth (Lymantria dispar L) was monitored in laboratory conditions, on the foliage of the species Quercus cerris L. Quercus petraea (Matt) Liebl. and Quercus robur L. The experiment was established in the controlled environmental conditions, at the temperature of 25°C, photoperiod 14:10 (day: night) and relative humidity 70%. The objective of the research was to determine the suitability of the study host plant species for gypsy moth development. The study results show that Gypsy moth caterpillars cultivated on Q. petraea foliage had a lower survival, higher number of moultings, longer preadult development and lower fecundity, which makes this species less suitable compared to the other two. Gypsy moth caterpillars cultivated on Q. cerris foliage had the highest survival degree the lowest number of moultings, the shortest preadult development and the highest fecundity, which makes this species the most favourable for gypsy moth development. Q. robur was between the former two species in this respect

Gypsy moths and American dog ticks: Space partners

An experiment intended for the space shuttle and designed to investigate the effects of weightlessness and total darkness on gypsy moth eggs and engorged American dog ticks is described. The objectives are: (1) to reevaluate the effects of zero gravity on the termination of diapause/hibernation of embryonated gypsy moth eggs, (2) to determine the effect of zero gravity on the ovipositions and subsequent hatch from engorged female American dog ticks that have been induced to diapause in the laboratory, and (3) to determine whether morphological or biochemical changes occur in the insects under examination. Results will be compared with those from a similar experiment conducted on Skylab 4