Pathological Anatomy of Eastern White Pine Needles Injured by Exposure to Known Dosages of Ozone and to Ambient Conditions in Acadia National Park [Final Report]

Merrill, William; Wenner, Nancy

'1. Several foliage-feeding insects are associated with Pinus strobus throughout the northeastern U.S. In 1993, two of these, the pine chafer [Anomala oblivia (Coleoptera:Scarabeidae)] and the pine chrysomelid [Glyptoscelis pubescens (Coleoptera:Chrysomelidae)], caused various amounts of damage, often extensive, to current-year needles of trees throughout Acadia NP. Their injuries are easily diagnosed. These insects play no role in the recurring 'blighting' of current-year needles on 'normally symptomatic' trees.' '2. Five needlecast fungi have been found infecting Pinus strobus in the eastern U.S. These are Lophodermium nitens, L. seditiosum, Bifusella linearis, Meloderma desmazierii, and a previously undescribed genus and species that we have temporarily named the 'BLA fungus'. These fungi sometimes occur in mixed infections, and they apparently have been confused with one another for years.' '3. The BLA fungus is the only organism thus far consistently associated with early summer blighting of current-year needles. It has been found associated with such symptoms from North Carolina to central Maine.' '4. Eight other fungi, often mixed infections, are often associated with blighted needles. Two are known secondary organisms. The specific identities and roles of the other six have not yet been determined.' '5. None of these fungi were found on damaged foliage in the open-top chambers.' '6. Needle damage to clonal materials in the open-top chambers was not related to levels of ozone exposure.' '7. The pathological anatomy of 'blighted' foliage from symptomatic field trees differed from that of damaged needles from clonal materials in the open-top chambers.' '8. The pathological anatomy of 'blighted' foliage from symptomatic field trees generally agrees with the pathological anatomy of 'simi-mature tussue needle blight' described by Linzon.' '9. The pathological anatomy of damaged needles from clona materials in the open-top chambers was different from that described for needles damaged by ozone, and also somewhat different from that described for drought.' 'We conclude that whatever is happening to the trees within the open-top chambers that results in needle necrosis is no what is affecting their parent trees in the field.' Contains descriptions of the insects and fungi observed on blighted needles /STUDY LOCATIONS:/ /ACADIA NATIONAL PARK/