Scope And Limitations of Carbendazim H2PO4 Injections In Dutch Elm Disease Control

Abstract

Since Dutch elm disease (DED) was first discovered in North America in 1929 and its full impact on our native elms became obvious, many control methods have been developed and implemented in an effort to save the elm. At first, attempts were made to eradicate the disease; when the attempts failed and it became apparent that DED was here to stay, efforts were made to restrict the spread of the disease by quarantine and sanitation measures. The quarantine measures were designed essentially to prevent movement of elm material from a diseased region to a non-diseased region. Sanitation measures were designed to reduce the populations of elm bark beetles (the insects responsible for transmitting the disease-causing fungus from infected to healthy elms) by removal and destruction of all elm material that was suitable for bark beetle breeding purposes. Despite these measures, the disease continued its rapid spread. Insecticide spray programs (first with DDT and later methoxychlor) were initiated but for the most part these failed when DDT was banned and an effective and ecologically safe substitute could not be found. To date, none of these measures, when used alone, has proved successful over the long run. Countless cities, towns, villages and countrysides have lost most of their elms to the disease. In North America DED now extends from the Atlantic to the Pacific. Most of the early control measures were designed to reduce losses of elms within a designated control area, wherein all elms were considered equal. Therefore, once an elm became infected, regardless of its value, it was slated for removal. No elm, regardless of its historic or aesthetic value, could be protected with any assurance. However, with the development of solubilized carbendazim and various in