Juniper dwarf mistletoe, Arceuthobium oxycedri (DC.) M. Bieb, in Balochistan Province, Pakistan

Abstract

Arceuthobium oxycedri, occurs from central Spain, across southern Europe, North Africa, the Near East, the Himalayas and western China where it infects Juniperus species and other hosts of the family Cupressaceae. In Pakistan, A. oxycedri is presently known from a single location, the Ziarat Forest, an 88,000 ha forest of J. excelsa in northern Balochistan Province where it presently encompasses a more or less contiguous area of approximately 3,500 ha, or about 4% of the total forest area. A. oxycedri occurs over much of the upper headwaters of the Chasnak and the Sasnamana Valleys of the Ziarat Forest. In the infested portions of the Chasnak Valley, an estimated 31.76% of the host trees are infected with a mean area dwarf mistletoe rating (DMR) of 1.53 and an estimated 2.03% annual mortality rate. Nearly 50% of the infected trees have a DMR of 6. By contrast, an estimated 22% of the trees in the Sasnamana Valley are infested with a mean area DMR of 0.52. No recent tree mortality, directly attributable to A. oxycedri, was detected in the Sasnamana Valley and nearly 50% of the infected trees have a DMR of 1. A. oxycedri was also detected in portions of four adjoining drainages. It is estimated that these infestations have been present for at least 25 to 30 years. In two of the drainages, the host tree is widely scattered and there is only a limited potential for tree-to-tree spread. In the remaining two valleys, infestations occur in relatively well stocked forests and there is a high potential for tree-to-tree spread.