Low Temperature Damage to Dwarf Mistletoe Fruit

Abstract

Early frost damage to dwarf mistletoe (Arceuthobium sp.) fruit was observed in the field, but the intensity of cold and duration of freezing temperatures were not recorded. In a controlled environment, exposure to −3.9 °C for about 2.3 h for lodgepole pine dwarf mistletoe (A. americanum Nutt. ex Engelm.) and for 2.0–4.8 h for hemlock dwarf mistletoe (A. tsugense (Rosend.) G. N. Jones) was necessary to cause permanent damage to the fruit. Field observations indicated that early fall frosts reduced the capacity of hemlock dwarf mistletoe to disperse seeds forcibly by 95%.