Treesearch

Gypsy moth cohorts from 10 near-wild strains (one to six previous generations in culture), six wild strains (field-collected egg masses), and the standard "New Jersey" lab strain (34th and 35th generation in culture) were reared on Otis wheat germ-based artificial diet, in a constant environment. Rearings were begun with newly-hatched first instars; pupae were later collected daily, sexed, and weighed. Pupal lengths and maximum body widths were measured for some lab strain females. Collected pupae were classified as morphologically "normal" or as possessing at least one of seven types of...

The fungal pathogen causing extensive mortality in gypsy moth larval populations during the 1989 field season has been identified as Entomophaga maimaiga. Identification was based on morphology and in vitro culture requirements, as well as results from allozyme and restriction fragment linked polymorphism analyses. E. maimaiga is well known to cause spectacular epizootics in Japanese gypsy moth populations but has not been reported from North America previously.

The Otis New Jersey gypsy moth (Lymantria dispar L.) strain is considered the "white rat" of gypsy moth research. This strain has been laboratory reared for 34 generations. It currently consists of 35 subcolonies or cohorts that have been genetically isolated from one another for several generations. Usually, larvae that hatch at the same time develop synchronously; however, in recent years this strain has been plagued by periods of asynchronous larval growth (straggling) and other performance abnormalities. These abnormalities are now collectively called Abnormal Performance Syndrome (APS).

Within the last ten years considerable research has been directed toward the development of a gypsy moth monitoring system for project planning at a regional level and for making control decisions at a local level. Pheromones and pheromone-baited traps have been developed and widely used and several egg mass sampling techniques have also been developed. Recently these sampling techniques have been combined into a pheromone trap-based monitoring system which uses pheromone trap results to assist in prioritizing areas to received egg mass samples. This approach has also made extensive use of...

The techniques and methodology for sampling gypsy moth, Lymantria dispar L., at low densities, less than 100 egg masses/ha (EM/ha), are compared. Forest managers have constraints of time and cost, and need a useful, simple predictable means to assist them in sampling gypsy moth populations. A comparison of various techniques coupled with results of recent habitat research studies indicates that a series of burlap banded trees can be utilized to monitor egg-mass density change over time. Egg masses beneath bands accurately reflect densities on unbanded trees, yet are easier to deploy and...

Specimens of gypsy moth, Lymantria dispar (L.) sensu lato were displayed in museum trays. Many specimens were quarantine laboratory reared during the 1989 season to provide samples (wing venation, frozen adults, prepupal haemolymph, larval feeding behavior, egg mass hair color, head capsule coloration and larval development) for various studies. Material reared was from HOKkaido, HONshu, and KYUshu, JAPAN; BEIjing, CHINA; Sibenik, YUGOSLAVIA; Queen Annes, MARYLAND (QAMD); and our standard BIRL culture. All (except HON) were individually reared (60 specimens each) in the first rearing using...

Defoliation of trees by the gypsy moth (Lymantria dispar L.) has many and varied effects. It causes economic losses through lost forest production and reduced aesthetic qualities of the forest. However, defoliation may improve habitat for many species of wildlife and contribute to increased diversity of eastern forests. Effects on water resources, recreation, and other values differ with different levels of defoliation and different forest types. Primary and secondary effects of defoliation on forested ecosystems are reviewed.

The manager needs tools for assistance in planning and interpreting monitoring systems. We are building a system that designs sampling programs by interpreting data about Gypsy Moth, stand condition and management objectives. The system prioritizes areas within the management unit within budgetary constraints and defines the areas to be monitored. The system proposes monitoring procedures to guarantee an effective monitoring program. These tasks are accomplished by the following modules in the GypsES system: The Egg Mass Sampling Designer (EMSD), the Pheromone Trapping System Designer...

During a 1985 European expedition, 5 species of microsporidia were obtained from gypsy moth collected in Portugal Czechoslovakia, and Bulgaria. From 1986-1989, we released all 5 species of these microsporidia into gypsy moth populations in isolated woodlots in Maryland. This presentation is a summary of the conclusions and recommendations based on the results of our experimental releases.

Recent experimental findings demonstrate that two distinct waves of mortality of gypsy moth larvae from nuclear polyhedrosis virus (NPV) occurs during larval development. The evidence suggests that early instars acquire lethal doses of NPV from the surface of the egg mass and the cadavers of these larvae produce inoculum that causes a second wave of mortality among late instars. Transmission of NPV between gypsy moth generations appears to occur primarily by way of contamination of egg masses from environmental sources during oviposition. Other factors influencing NPV epizootiology...