Procedures for Laboratory Studies on Wood Decay Resistance

Laboratory studies on wood decay resistance are useful in both research and teaching. These studies have been used extensively to determine decay resistance of tropical woods to wood rot fungi found in the temperate regions of North America (9, 16, 20, 25, 26, 27). The methods have been used or suggested as tools in basic research on fungal ecology (4, 13, 14, 17), abnormal wood (5, 6, 12, 24) and wood variability (8, 21, 22, 28). The techniques also are adapted for use as laboratory exercises in a Plant Pathology course, especially if conducted in conjunction with other laboratory deterioration procedures (18, 23, 29). Because of these uses, the suggestion was made that these laboratory procedures be presented in their entirety. This paper is an attempt to achieve this purpose

The Status of Oak Wilt in lowa

This paper is intended to review critically and briefly the research being conducted on the oak wilt disease caused by the fungus, Endoconidiophora fagacearum Bretz. Although conditions and work in Iowa will be referred to constantly throughout the course of this review, much of the material will be applicable to the other oak wilt areas of this country. Many old time woodsmen maintain the presence in oak stands at the turn of the century of what we now call oak wilt; but the first definite occurrence of this disease is indicated by photographs taken in the McGregor area in 1932 (Dietz and Young 1948). By 1943, oak wilt became a serious threat to the oak areas in northeastern Iowa and in the state parks of Dolliver and Pilot Knob. Since that time, oak wilt has been found to be present throughout the oak range in Iowa. At this writing, nationally, this disease is considered the most serious forest tree disease in the eastern half of the United States. Research was begun on this disease in the early 1940\u27s by workers in Iowa and Wisconsin with the support of their respective conservation commissions. As the disease became known in other areas of the country, more research programs developed. In 1950 the National Oak Wilt Research Committee, a group of men in the hardwood industry, was formed and has financially supported oak wilt research at six research institutions since that date. The federal government as well as other state and local agencies have also actively supported oak wilt research in the oak regions of this country. At this time, eleven states are active in research on this disease

A New Look at Dutch Elm Disease Control

Dutch elm disease, caused by the fungus, Ceratocystis ulmi, has become the most serious tress disease in North America

Notes on Stem Rusts of Hard Pines in Iowa

Tree disease specimens sent to Iowa State College for identification, during the past two years, have yielded what is believed to be two new rust records for Iowa. Because of this, and the fact that under certain conditions these diseases could become important, a few comments on these collections are presented

Measurement of Xylary Fluid Movement in Elm by the Thermoelectric Method

The thermoelectric method was used to determine the effect of external conditions and diurnal variation on the direction of xylary fluid movement in elm branches. Upward movement was detected under conditions favoring normal transpirational rates. No movement was detected during darkness or rainy conditions. Possible downward movement of branch fluid was indicated during late afternoon. Further refinement of the technique is needed for clarifying the latter observation