Some samples can be destructive in nature, though staff try to minimize the operational and economic impact. Surveying for JB in containers is done by removing plants from pots, examining the potting media for life stages, namely grubs and pupae. More details on the JBHP that was revised in 2016 and became effective Janucan be found at: This is meant to discourage egg laying in and around nursery containers. This certification method requires that container grown stock must be kept on an impervious surface such as gravel. It is important to note that even stock that is in compliance with the Japanese Beetle Harmonization Plan (JBHP) for container accreditation can become infested. The adults can cause significant damage to a number of plants feeding on and skeletonizing leaves and feeding on flowers and fruits. Turf that is fertilized and irrigated is particularly attractive for adult beetles to lay their eggs and for grubs to happily munch away until they pupate and emerge from the soil as the adult beetles the following year. Japanese beetle grubs spend their lives below ground feeding on roots. As a result, nursery stock has become more commonly infested both by the adult beetles, and in a recent incident as grubs and pupae in container grown nursery stock. Minnesota has seen an increase in population and spread of Japanese beetle ( Popillia japonica) to more locations around the state over the past few years. Steven Shimek, Nursery Program Coordinator Some of the many true fir needle and shoot blights also cause damage to Sitka spruce, and white spruce foliage.Having trouble viewing this email? View it as a Web page.Ī Newsletter for the Minnesota Nursery Industry There are three species of true fir, Abies spp., in the Pacific region: amabilis fir, occurs west of the Coast Mountains alpine fir, occurs generally above 1200 m along the Coast and is scattered throughout the Interior into the Yukon Territory, and grand fir, occurs at lower elevations on Vancouver Island and the adjacent mainland coast, inland to the Hope area, and in the southern region of the southwest Kootenays.
Canadian Forest Service Publicationsįir needle cast ( Lirula abietis-concoloris) Information on host(s)
No asexual spores are produced by this fungus. The sexual spores are wind-borne and can infect only the new needles, thus completing a 2-year life cycle. The following spring, the infected needles turn pale and tawny the fruiting bodies become very dark, large and conspicuous, and split open when mature. Immature fruiting bodies appear as thin, dark brown lines on the underside of these reddened needles in late summer. Wind disseminated sexual spores infect needles on the newest growth from June until August, and by the following spring, the needles turn red and die. Discoloured infected needles are often intermingled with a few healthy green needles, unlike frost or drought discolouration, when whole branches or portions of the crown are uniformly discoloured.Įach blight has a different life history and many are incompletely known that of Isthmiella quadrispora is presented as an example.
This discolouration is frequently restricted to particular annual increment of foliage. The most conspicuous symptoms of needle blights are red, yellow or brown discoloured needles, which may later turn grey. the "sexual" fruiting body, which is generally large, occurs along the mid-ribs of the lower needle surface e.g., Lirula punctata.the "asexual", which occurs like small dots on the upper surface of the needles, e.g., Lirula punctata.Generally two types of fruiting bodies develop during the life cycle of blight fungi: Lower branches and understory trees are frequently the most seriously blighted as the more humid conditions favor infections.Įconomic damage caused by the needle blights is conjectural. Blights are more common following wet springs. Lirula abietis-concoloris causes damages on 1-year old infected needles.Ĭlimatic conditions influence spore dissemination and germination, and thus the frequency and severity of infection. The degree of damage can be influenced by the age of the host tree older trees are more resistant to damage and infection of older needles is eventually harmless. Heavily infected trees have an unsightly appearance caused by needle discolouration.
Seedlings may be severely damaged if a high percentage of the foliage is infected. Only a few of the many blight diseases in British Columbia are known to cause serious damage which is limited to increment loss tree mortality is not known. Severe infection can result in significant growth reduction. Needle and shoot blights are caused by a related group of fungi (Ascomycetes), which cause more damage to coniferous foliage in North America than any other group of fungi. This blight is widely distributed throughout the range of its hosts in the interior and coastal regions of British Columbia.
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