1. INTRODUCTION

Dwarf mistletoes are parasitic seed plants of the genus Arceuthobium. This group of plants parasitizes conifers of the families Cupressaceae and Pinaceae and is the only mistletoe genus present in both the eastern and western hemispheres. Many dwarf mistletoes are destructive pests of forests, causing reduced increment and tree mortality. This is especially true in North America (Canada, Mexico and the United States) where the greatest number of dwarf mistletoe species are found. Dwarf mistletoes are also found in other parts of the world including Central America and the Caribbean Basin, the Mediterranean region of Europe and North Africa, East Africa, the Near East and Asia.

The damaging effects of the dwarf mistletoe, A. oxycedri, has caused concern about the future of extensive juniper forests in the Province of Balochistan, Pakistan. These forests are considered to be among the most extensive juniper forests in the world and are known to contain individual trees which are at least 2000 years old. The management of this potentially destructive parasitic plant is being considered as an integral component of a Balochistan Natural Resources and Conservation Project financed by The World Bank. This review of dwarf mistletoes is a first step in the planning and execution of a forest pest management program directed against minimizing the effect of this parasitic plant on the Juniperus forests of Balochistan.

Objectives of this review are to:

  1. Present a general overview of dwarf mistletoes, their biology and control.

  2. Provide an in-depth review of the biology and management of dwarf mistletoes which affect conifers of the family Cupressaceae.

  3. Review the current status of dwarf mistletoe in Balochistan.

Dwarf mistletoes in general and, more specifically the North American species, have been the subject of two comprehensive reviews, Hawksworth & Wiens 1972 and Hawksworth & Wiens 1996. In addition, this group of plants has been the subject of two national workshops held in the USA (Scharpf & Parmeter 1978, Hawksworth & Scharpf 1984). These documents, plus the computerized data base on dwarf mistletoe literature, maintained by the Rocky Mountain Forest and Range Experiment Station, USDA Forest Service, Fort Collins, Colorado, (Scharpf et al 1976) formed the basis of this review.