Increment cores were collected from 10 stands in mixed-conifer forest stands which had suffered varying levels of Douglas-fir tussock moth defoliation during 1946, 1964, and 1973 infestations in north central Idaho. Ring-width measurements, standardized to remove inherent growth trends, were compared between host (Douglas-fir and grand fir) and nonhost (western larch, ponderosa pine, western white pine) species for evidence of growth losses due to defoliation. Heavy defoliation caused growth of host species to decrease 75 %-90% in one year. Normal growth rates returned within 3-4 years after maximum defoliation, however. The effect of moderate defoliation could not be reliably identified in the data.

No description available.

No description available.

Digitized by Kansas Correctional Industries

Naturalists, state administrators and farmers in France and its colonies developed a myriad set of techniques over the course of the long eighteenth century to manage the circulation of useful and harmful insects. The development of normative protocols for classifying, depicting and observing insects provided a set of common tools and techniques for identifying and tracking useful and harmful insects across great distances. Administrative techniques for containing the movement of harmful insects such as quarantine, grain processing and fumigation developed at the intersection of science and statecraft, through the collaborative efforts of diplomats, state administrators, naturalists and chemical practitioners. The introduction of insectivorous animals into French colonies besieged by harmful insects was envisioned as strategy for restoring providential balance within environments suffering from human-induced disequilibria. Naturalists, administrators, and agricultural improvers also collaborated in projects to maximize the production of useful substances secreted by insects, namely silk, dyes and medicines. A study of these scientific and administrative techniques will shed light on how scientists, administrators and lay practitioners in the French Enlightenment came to assess and manage the risks and opportunities afforded by the related processes of commercial and ecological globalization.

No description available.

Includes bibliography.

Chrysopa carnea Stephens is widely distributed throughout the world. The larva is a potential control agent of pests in greenhouses, field crops and orchards. Its use as a biocontrol agent in integrated control is enhanced by its tolerance to some insecticides. Because of its considerable usefulness, studies to investigate the bionomics of this predator under both laboratory and field conditions were initiated. The study of population dynamics in alfalfa fields indicated that the major factors which govern the fluctuation of Chrysopa are: climate, food (e.g. aphids), diseases, parasites and agricultural practices (e.g. cutting of alfalfa hay). In each year and for each field, it was apparent that population levels of larvae rose to peaks five to six times; this suggests that there are five to six generations per year. The study of the effect of temperature and photoperiod on development in the laboratory showed that the egg, larva and pupa responded significantly to both temperature and photoperiod and an interaction between these two parameters was detected. Relative to fecundity and longevity, the investigations revealed that there was a photoperiod response only with respect to number of eggs laid and preoviposition period and that interaction between temperature and photoperiod was absent. In the case of the oviposition period, a response to temperature was detected and interaction between temperature and photoperiod existed. The different regimes had no significant effect on longevity of either sex. Consumption of prey differed significantly--being highest with beet armyworm eggs (Spodoptera exigua (Hubner) followed by corn earworm (Heliothis zea (Boddie) and tobacco budworm (Heliothis virescens (Fabricius). Fewer pea aphids (Acyrthosiphon pisum (Harris) were consumed than any of the lepidoterous eggs. Resistance to starvation differed significantly among the three instars; the newly-emerged Chyrsopa larvae had the shortest survival period. Studies on consumption of different instars of tobacco budworm by different instars of the predator indicated that the first instar was most vulnerable to attack by each of the first and third instars of the predator. Experiments were conducted to determine the effects of cold storage (4.4°C) of eggs and pupal cocoons for different periods of time. The results indicated that percent egg hatch and survival of emerging larvae were highest when stored for one week. Pupal storage for different periods had no detrimental effect on survival of pupae nor fecundity of emerging adults.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.