We went for a picnic at Lake Rotoiti, Nelson Lakes National Park, last Saturday (24 January 2015) and went for a walk through the southern beech forest along Bellbird and Honeydew tracks on the eastern side of the lake. As weather conditions over much of New Zealand are being described as pre-drought (at some point government will agree that it is a drought (Manning, 2015)) I was surprised to see any mushrooms at all.On the side of the track under Nothofagus menziesii and N.solandri was a small group of lonely chalkcaps (Russula solitaria) with their pale brown caps. All of the mushrooms that I saw were drying out and past their best for good identification. Further along the track, under Nothofagus solandri, where a few isolated magenta chalkcaps (Russula umerensis) [see A mainland island in the making: Kaipupu Point]. I saw a single specimen of a Cortinarius, probably Cortinarius alboroseus. This was originally in a small genus call Cuphocybe as Cuphocybe alborosea. However molecular analysis has reduced Cuphocybe to a synonym of Cortinarius. Cuphocybe was recognised by its slimy cap. obviously missing under these dry conditions, and a flat foot to the base of the stem. All in all not too bad for drought conditions. References Department of Conservation. Lake Rotoiti walking tracks. Link here Manning B 16 January 2015. New Zealand faces drought if rain brushes past. New Zealand Herald Link here
The last few weeks have seen a series of cold wet fronts push across New Zealand interspersed with hot dry highs giving a very mixed bag of weather – typical Wellington. As today was such a beautiful day we walked up to the Te Ahumairangi Trig lookout and then down through the town belt, the Northern Walk, to St Mary St, Thorndon.The vegetation of is described in from the Wellington Town Belt Management Plan – June 2013:
Te Ahumairangi (formerly known as Tinakori Hill) is a prominent ridge rising to 300m between the suburbs of Northland and Wadestown providing a backdrop to the central business district and Thorndon. Its height and dark colour make it [the escarpment] a dominant backdrop to inner city high-rise buildings.
The escarpment comprises the steep eastern vegetated hillsides facing the city containing a mosaic of pine forest and regenerating native forest, with deciduous woodland of primarily oak trees below Wadestown Road. On the lower slopes and in some places further up the steep gullies are large infestations of sycamore. The steep topography coupled with the abrupt edge at the base of the escarpment next to Grant Road limits access along this edge. The landscape is in a period of change following the removal of 10.5ha of hazardous trees in 2005 and 2006.
Te Ahumairangi Hill has undergone major changes in vegetation structure as a result of the storms of February and August 2004 that caused severe damage to the existing conifer forest. Over 10.5ha of conifer forest were damaged and subsequently removed. It is essential that during this period of major landscape change the distinct character of the hill is maintained as far as is practicable.
Just below the lookout the track cuts through the remain standing of pines [Pinus raditata]. The weather has stimulated some of the mycorrhizal mushroom species associated with pine to fruit early.Two species were seen fruiting on the damp ground between the edge of the track and the bank. The first was the pine chalkcap [Russula amoenolens]. See my earlier comment about this species here. The second species was the sticky-bun bolete [Suillus granulatus]. Read my earlier comments on this species here and here. Having got to St Mary St and Glenmore Rd we walked up the other side of the Valley through the Botanic Garden. Here was a third mycorrhizal mushroom species – the slippery-jack bolete [Suillus luteus].
After eating far too much for Christmas lunch we went for a walk across Ian Galloway Park to Karori Cemetery. A the edge of the playing field in Ian Galloway Park there is a row of pines (Pinus radiata) [see earlier blog].Under the pines there was a small cluster of large, immature, Agaricus mushrooms. I had some correspondence with Edward Bowers last year about a similar mushroom and he suggested that this might be Agaricus bitorquis. The association with pine may be only incidental as Agaricus bitorquis is considered a grassland or pasture species.
It is a week before Christmas and we have been having wet humid weather so after doing some Christmas shopping this morning I walked home from the central city home to Northland. The harbinger of Christmas are the pohutukawa [Metrosideros excela] which are beginning flowering all through the city. These are by the Civic Centre near the harbour foreshore.On the edge of the central business district is the Bolton Street Memoral Park. Back in May I lamented the removal of a stump that I had been recording the fungi on. Well you can’t keep a good fungus down and although the stump had been removed most of the major roots are still in place. This photo shows Crumble inkcap [Coprinellus micaceus] grow on a dead root. In the fuchia garden that runs along the edge of the main garden and Glenmore St there was a clump of roundhead [Psathyrella] possibly Psathyrella conophila see earlier blog. These little roundheads are common on wood mulch. Close to the roundhead was a disintegrating Common scabbard [Volvariella gloiocephala = V. speciosa].
Near the west entrance near the intersection of Glenmore St and Orangi Kaupapa Rd there is the fallen oak [Quercus robur] which has been mulched under to control weeds. There was a good fruiting of scarlet pouch [Weraroa erythrocephalus = Leratiomyces erythrocephalus] see earlier blog. Leaving the Botanic Garden and begin the climb up Orangi Kaupapa Rd this Ganoderma applanatum was grown on a stump just below the intersection with Garden Rd. All around the footpath here is a thick mat of the invasive weed Tradescantia fluminensis which can be seen in the photo.
Almost home. Looking back from Garden Rd across the Botanic Garden to the city and harbour.
As we move towards late spring and early summer in the southern Pacific mushrooms are few and far between as conditions become dryer. The bit of rain that we had last weekend and early in the week produced this flush of crumble inkcap [Coprinellus micaceus]. Although appearing to be growing on soil the wood decay fungus is growing from the dead root of a near by tree [pohutukawa, Metrosideros excelsa].
A feature of spring in Wellington is tulip day at the Botanic Garden. According to the Friends of the Wellington Botanic Garden tulip day started in the 1940s. It is possible that the first tulip day was 16 October 1944 from information supplied by the Wellington City Archive however it became a significant event in 1948 following a donation of tulip bulbs by the Netherland’s government as a thank you for sheltering children during WWII. The gardeners plant about 24,000 bulbs for the spring display.Since moving back to Wellington last year I walk to work through the main garden and have watched the preparation, planting, and the emergence of the tulips over the last few months. At the end of last week large area of tulips in one bed were removed and the bed mulched over. Signs have been erected and articles in the local papers explain that this bed has been badly affected by the disease ‘tulip fire’ (Anon, 2014). The disease is caused by a fungus Botrytis tulipae which infects all parts of the plant causing grey to brown lesions which may join up to cause a general dieback of the emerging tulips. For a disease to develop there needs to a pathogen (Botrytis tulipae), a susceptible host (tulip), and a favourable environment. This is known as the disease triangle. In this case we have had the pathogen since before 1948 (Dingley, 1969) but do we have the other two factors? According to Cornell University’s fact sheet a favourable environment is “cool (15°C), rainy spring and summer weather … can be particularly damaging when rainy, drizzly weather continues over several days”. Well, that pretty much describes Wellington weather most of the time.
So, we have two of the factors for disease development. That just leaves a susceptible host? The Botanic Garden has been growing tulips annually in these flower beds for 70 years with a low incidence of disease. The tulip cultivar most affected is the bright pink ‘Carola’ which was planted for the first time last year. So here is our susceptible host.Botanic Garden staff members removed many of the worst diseases plants to control the spread of the disease and intend to apply “a one-off fungicide to nip it in the bud” (Anon, 2014). While this will solve the immediate problem what other long term solutions are available? Then most obvious is to break the triangle and not grow susceptible cultivars such as ‘Carola’.
The second is to reduce the presence of the pathogen in the soil. Botrytis tulipae forms black survival bodies or sclerotia which survive in the soil when tulips are not present.These could be eliminated by treating the soil with fungicide or other chemicals but this is not environmentally friendly. The other approach is to implement crop rotation as you would do in a vegetable garden. Interestingly there is not much written about this and I found only one article about in the Otago Daily Times (2014):
Crop rotation in the flower garden is also possible. Stocks and wallflowers in mass displays exhaust the soil in similar ways and should not follow each other. Likewise, if dahlias are grown in the same soil year after year, they will make excessive demands on some soil elements and plant quality will drop. Ideally, dahlias, gladioli, pansies, violas, tulips, hyacinths and narcissi should be planted in different areas of the garden each year. Rose-planting time has arrived and nurseries soon will be full of this most popular shrub.
The challenge in gardening is to work with natural processes to achieve the desired outcome. Look forward to seeing you at Tulip Sunday 21 September 2014 – enjoy the flowers and understand the fungus.
Amand, J. The tulip gallery. http://www.thetulipgallery.com/view/859
Anon, 2014. Council gardeners fight fire for tulip Sunday. Independent Herald (Wellington, 17 September 2014): 18.
Cornell University, 2013. Botrytis blight of tulip. Plant Disease Diagnostic Clinic. http://plantclinic.cornell.edu/factsheets/botrytisblighttulip.pdf
Dingley, J.M. 1969. Records of Plant Diseases in New Zealand. DSIR Bulletin No. 192. Government Printer: Wellington, New Zealand.
Friends of the Wellington Botanic Garden. Tulips. http://friendswbg.org.nz/newTULIPS.htm
Jensen, S. 2012. Mycelial neck rot. Cornell University, Bugwood.org http://www.insectimages.org/browse/detail.cfm?imgnum=5458101
Otago Daily Times, 2014. Crop rotation important for healthy garden. 27 June 2014. http://www.odt.co.nz/lifestyle/home-garden/307255/crop-rotation-important-healthy-garden
Plant Pathology at the University of Wisconsin-Madison, General Master Gardener Training. The disease triangle. http://www.plantpath.wisc.edu/PDDCEducation/ppt/img1.php
The photo below was taken 7 October when the last of the disease affected ‘Carola’ tulips had been removed from yhe infected bed. What was left was the ‘Black Diamond’ cultivar which is obviously has a resistance to the pathogen.
My first recollection of eating field mushrooms [Agaricus bisporus] collected from cattle paddocks just outside of Shannon in 1968. What I recall most about the meal was the ample black liquid that they cooked in and how it turned the toast grey and soggy. This reminiscence was prompted by an article in the business pages of the Dominion Post (Harris 2014) about Clive Thompson, owner of Parkvale Mushrooms in Carterton. Parkvale Mushrooms sells 7-8 tonnes of mushroom a week as well as 50 tonnes of used compost a week and an annual turnover of $3.2m.
New Zealand has 7 commercial mushroom growers producing 8,500 tonnes of mushrooms annually which are worth $41.1 million in domestic sales (Fresh Facts, 2013). Our biggest producer, Meadow Mushrooms in Christchurch, produces on average 147 tonnes of mushrooms a week.
Because fruit rots so easily in a fruit bowl and bread goes mouldy in the bag growing mushrooms should be easy. All you need to do is introduce the fungus to the compost, let it rot and out will pop the mushrooms! Biology is never quite that simple. There is a great article although a little old now written by Stephen Brightwell in New Zealand Geographic in 1993 about commercial mushroom production. For a more recent description see the Mushroom Growers Federation NZ’s website.
The basic process is shown in this diagram from Brightwell (1993).
Compost is made from wet straw, animal manure (usually chicken), and gypsum (calcium sulphate). In a large operation like Meadow Mushrooms the wet straw is heaped into rows and a machine used to turn the composting straw to keep it aerated which helps to maintain a temperature of 65–80°C and to speed decomposition. At this high temperature carmelisation occurs where water is driven out and carbon is concentrated and the compost has a strong smell of ammonia. This is the end of phase I composting.
In phase II composting the compost is kept warm and aerated to promote a second bloom of microorganisms and cause the buildup of heat which will pasteurise the compost. Pasteurisation effective kills any unwanted pests and pathogens of mushrooms. In the cool down period following pasteurisation an array of microorganism flourish which convert any remaining ammonia into protein and other nitrogen compounds the mushroom can use. This is called conditioning of the compost.
When the composts temperature drops to 30°C it is inoculated with fungal spawn. Spawn is made by growing the fungus on cooked rye or other seed. When the seed has been fully colonised by the fungus it is mixed with the compost and the fungus grows out through, colonising, the compost.
The colonised compost is then packed into wooden, stackable trays or onto long metal shelves in mushroom shed where temperature and humidity are controlled for optimal colonisation of the compost. Once this occurs the trays or shelves are cased. Casing is putting a 4-5cm layer of peat and lime across the surface of the compost.
When the casing has been colonised the sheds’ environment is regulated to control the levels of carbon dioxide, humidity and air temperature. Under these controlled conditions mushrooms begin to form. Generally 3 or 4 flushes can be expected over 4-6 weeks.
Once picked the mushrooms are ready for eating. Richard Till’s (2011) recipe is probably as close as it gets to what I remember as a kid.
Mushrooms on toast
½ cup flour
1.5kg cleaned field mushrooms
(or flat cultivated mushrooms)
Melt butter in a large saucepan.
Add flour and stir over a low heat for two minutes.
Add milk and whisk together over a medium heat until the mixture thickens. It will be very thick. Add one teaspoon of salt.
Roughly chop, or crumble the mushrooms into the white sauce, and mix together.
Cover and reduce heat to low. Stir frequently.
The mushrooms will release liquid and the mixture will become quite watery. Remove cover and cook for a further 30 minutes to an hour, until the mixture is thick.
Allow to cool and, if possible, refrigerate overnight.
Reheat and serve on thick slices of buttered toast.
Brightwell S 1993. Feasting on fungi. New Zealand Geographic 18 (June): 34-58. http://www.nzgeographic.co.nz/archives/issue-18/feasting-on-fungi
Fresh Facts 2013. http://www.freshfacts.co.nz/file/fresh-facts-2013.pdf
Harris C 2014. Dream mushrooms into 43m venture. The Dominion Post (1 September 2014): B5. http://www.stuff.co.nz/business/small-business/10444484/Dream-mushrooms-into-3m-venture
Mushroom Growers Federation New Zealand. Myshroom growing process. http://www.mushroomgrowers.org.nz/mushroom-growing-process.php
Parkvale Mushrooms http://www.parkvale.co.nz/index.php
The Profit 2013. Mushroom magic. http://www.theprofit.co.nz/mushroom-magic/
Till R 2011. Man about the land: Magic mushrooms. Sunday Star Times (10 April 2011): E19.