Effect of Arceuthobium vaginatum (Willd.) Presl. subsp. vaginatum in Pinus hartwegii Lindl. in Colima State

Abstract

Although mistletoes are abundant in Mexico, very little is known about their behavior on different hosts. There is some work on damage assessments and less on the behavior of trees infested with varying degrees of attack. The aim of this study was to determine the effect of Arceuthobium vaginatum subsp. vaginatum in height, diameter and volume of Pinus hartwegii in the Nevado de Colima Volcano National Park. 18 trees were chosen in a natural stand in the presence of dwarf mistletoe: nine sick and nine healthy, aged between 30 and 40 years to which stem analyzes were performed to reconstruct their history of growth. Based on the classification system of Hawksworth, the degree of infection was considered 6. Schumacher and Chapman-Richards equations to find the most appropriate model for the description of the phenomenon were tested. The first one showed better fit in predicting growth. Dwarf mistletoe infestation reduced it at 22 % in height, 9 % in diameter and 50 % in volume; it also affected by similar percentages the current annual increment and the mean annual increment, which lowers the volume of timber produced and the wooden technical rotation increases, at an average of 10 years. These results suggest the application of practices to prevent and combat the parasite and the establishment of continuous monitoring sites for the generation of knowledge about the host-parasite relationship.