Rarity of a Fungal Pathogen and a Parasitic Flowering Plant Versus the Commonness of a Mycorrhizal Fungus in Pecan Orchards in New Mexico

Abstract

This study documents the occurrence of the fungal pathogen Inonotus rickii, which causes wood rot or heart rot; the leafy mistletoe Phoradendron tomentosum (subsp. macrophyllum); and the mycorrhizal fungus Pisolithus tinctorius in pecan orchards in southern New Mexico. The prevalence of orchards with I. rickii and P. tomentosum was low (3.3 to 3.6%). To our knowledge, I. rickii has not been previously described in association with pecan in New Mexico and the United States. Although the occurrence of P. tomentosum on pecan has been documented in the southeastern United States, it has not been reported in New Mexico. In contrast to the rarity of I. rickii and P. tomentosum, the mycorrhiza P. tinctorius was commonly found in pecan orchards surveyed. With the expansion of the pecan industry in New Mexico, it is important to continually monitor pecan orchards for emerging pests and pathogens that may impose an economic threat to production and to enhance the proliferation of biological entities with known beneficial properties for pecan health.