Horticulture Group Newsletter - November 2011

Cider production

The harvest
The Horticulture Group made two visits in October to study different aspects of cider production. First, in conjunction with the Professional Horticulture Group South West we toured the cider orchards of Bob and Bridget Wadey, near Shepton Mallett, Somerset. They have 42,000 of cider apple trees spread over 160 acres of two farms. Their main variety is Dabinett, a bitter-sweet apple but they also have areas of Harry Masters Jersey another bitter-sweet and Browns, a bitter-sharp apple. Rows of another bitter-sweet variety, Michelin, are planted regularly through the orchards. Michelin is an excellent pollinator and ensures good fruit set. Bee hives are brought into the orchards at flowering time for this purpose.

Most of the trees are grafted on to M111 rootstocks to the control their vigour although some are on M25 and the Browns, a particularly vigorous variety, are on the more dwarfing rootstock M106.

Our tour coincided with the harvest. This starts with a 'shaker' (pictured right) mounted on the back of a tractor. This device is steered to grab the base of the tree and shake it violently, causing most of the apples to drop to the ground. Any remaining apples are knocked off manually with sticks. The harvester then picks up the apples. Since these are randomly scattered, brushes on the front of the tractor sweep those in front of tractor and side sweep the apples into a 'windrow' which is then picked up by a pair of counter-rotating belts. These cleverly pick up hard ripe apples leaving any rotten windfalls behind. This first pass with the harvester usually leaves a proportion of good apples so a further sweep by a second pass is made to collect these. The harvested apples are then ready for the journey to the cider plant.

Pictures of the harvesting process can be viewed here.

Small scale production
Cider production was the subject of our second visit which started at Peter Mitchell's Orchard Centre at Hartpury near Gloucester. Peter does not grow any apples but buys in local hand-picked fruit. He demonstrated how the apples are first floated on water to enable any that are too badly damaged to be removed before they are milled to produce a coarse pulp. The pulp is placed in a series of polypropylene pockets which are then squeezed in a hydraulic press (pictured right) to extract the juice. This is then fermented in temperature controlled vats. A selected strain of bottom fermenting yeast is added together with nitrogen and protein supplements to aid the growth of the yeast.

The yeast is probably a hybrid between Saccharomyces cerevisiae and S. bayanus and related to the yeast used in champagne production. These strains prefer a lower temperature than the top fermenting strains of S. cerevisiae used for beer production. Initially the juice is maintained at 18-20^oC to start the ferment but this is then dropped to around 14^oC. It takes 14 days for fermentation to completely use up all the available sugar and the temperature is then raised to kill the remaining yeast. This settles out over two days after which this base cider can be drawn off.

Peter stores this in large bags of silvered plastic very similar to those in wine boxes. These keep the contents free from contact with the air and the base cider will store for up to 18 months. This raw cider is not very drinkable and must be blended to make the finished product. Fructose sugar is invariably added, even to 'dry' cider, as is some water and acid to 'balance' the pH before the final product is bottled for sale.

Pictures of this process can be viewed here.

Industrial production
The Group then went on to Westons Cider at Much Marcle in Herefordshire. Here cider production is similar to that described by Peter Mitchell but on an industrial scale. They can press 10 tons of fruit in 90min, fill 28,000 bottles an hour and last year sold over 6million bottles of cider. With such large scale production storage becomes a major issue especially the large oak vats where they 'finish' the cider. In addition to 24 ciders, they produce pear cider and perry.

The artisan
The final visit was to Gregg's Pit Cider run by James Marsden. James is an artisan producer and like Peter Mitchell, prefers his apples picked by hand. Some apples come from his own orchard and usually some from a neighbour. Unfortunately this year winds brought down his neighbour's apples which were then eaten by the cows he grazes in the orchard. His own orchard is some 300 years old and contains 33 varieties of cider apples and perry pears.

He uses an old stone press but polypropylene fabric replaces the traditional jute sacking to separate the layers of pulp. The cider is produced using a traditional method still widely used in France. This involves using apples that are rich in tannin but low in nutrient. These are macerated at low temperature (around 5^oC) and then calcium chloride added. At these low temperatures the pectin in the fruit turns to pectic acid which forms a gel with the calcium. This rises to the surface form a brown layer called a 'brown hat' or 'chapeau brun'. The clear liquid left when this 'hat' is removed is fermented slowly at low temperature with natural yeast to produce a naturally sweet cider.

Plant of the Month

Hydrangea quercifolia, Hydrangeaceae

This medium-sized shrub (picture top right by Anne Norman), which comes from South Eastern USA has leaves shaped like an oak tree (as its name suggests) - albeit, magnificent large oak leaves which turn a flaming red in the autumn (picture lower right by Derek Ramsey). The name hydrangea comes from the Greek hydor, meaning water and angos, meaning a jar and describes the cup-shaped fruit characteristic of this genus.

Hydrangeas are well known by gardeners for their showy inflorescence, which are composed of small and insignificant fertile flowers surrounded by far larger, yet sterile ray florets. Many hydrangeas have coloured flowers, with the flower colour being somewhat dependant on the pH of the soil the plant is growing in. The anthocyanin pigments turn from red in alkaline soil to blue in acid soil, dependant on the availability of Al³⁺ ions. The oak-leaved hydrangea, however, has snowy white flowers from mid-summer to mid-autumn and there are several cultivars available such as 'Snow Queen' and Snow Flake'. The flowers on these plants will be white regardless of the soil type upon which they grow.

Medicinal Plant of the Month

Dichroa febrifuga, Hydrangeaceae

This member of the hydrangea family is much less commonly grown in the UK. In part this is because it is not fully hardy and so unlikely to have survived the rigours of the past two winters. It is native to the mountains of China and Nepal.

The name Dichroa means twice-coloured from the Greek dis and chroa. The flowers are white to pale pink but the fruits when they form are a stunning royal blue colour. Febrifuga means fever-dispelling, and indeed this plant has long been used in traditional Chinese medicine against malarial fever. The active principles were isolated as long ago as the 1940s and found to be two isomers in equilibrium with each other whilst in solution. Named febrifugine and isofebrifugine, they rapidly kill the malarial parasite and there are no resistance problems. They are however too toxic to the liver to be progressed as a clinical drug. Research is underway to develop analogues that have a better safety profile.

News from our Associates

Commercial Horticultural Association
The CHA will be running the UK Pavilion at Hortifair in Amsterdam from 1 - 4 Nov. It will be hosting a seminar at the event on 3 Nov to promote the latest developments and technology from the British commercial horticulture industry.

In addition the CHA is still recruiting companies wishing to exhibit at IPM Essen, Fruit Logistica (Berlin), Salon du Vegetal (Angers) and Hortec Kenya

Horticulture Industry News

For the very latest horticultural news follow us on Facebook and or Twitter.

Money for tree research
Millions of trees could be lost to disease in the UK in the next few years unless urgent action is taken, Environment Secretary Caroline Spelman has warned. She was speaking at the launch of a new government drive to combat the exotic pests and diseases threatening the health of trees in the UK. People trying to smuggle potentially-infected plants and cuttings into the UK will face more robust enforcement, and the government is putting £7 million into research on combating new or exotic tree and plant pathogens. The Tree Health and Plant Biosecurity Action Plan, a joint initiative with the Forestry Commission, sets out how to tackle serious tree and plant pests and diseases. However, the funding is not new money from the Treasury. It is funding from within Defra's existing science budget that will be allocated to tree health and biosecurity research. More

Artificial vision to detect rotten oranges
A machine that uses artificial vision and Ultra-Violet rays to scan through citrus fruits and get rid of rotten ones has been developed in Spain. Usually the inspection is done manually in dark rooms, also using UV light. But this can harm workers' eyes and skin, so they must wear protective clothing and goggles. The team from the Valencian Institute of Agrarian Research said that their technology could eliminate these risks. More

Robot strawberry pickers
Scientists at the National Physical Laboratory have developed an imaging technology which can identify the ripeness of strawberries before they are picked. The developers now hope to work with the agricultural industry to turn it into fruit picking robots that will reduce food waste and improve productivity. Successful trials have been completed on strawberries as well as a number of other crops. The software has also been designed to 'learn' based on past experience, so tests for new crops can be quickly developed. The work began in 2009, as a project to identify the ripeness of cauliflowers, which was a problem for pickers due to their leafy exterior is now being developed for a wider range of fruit and vegetables. More

Trees boost African crop yields and food security
Planting trees that improve soil quality can help boost crop yields for African farmers, an assessment shows. Fertiliser tree systems (FTS) also help boost food security and play a role in 'climate proofing' the region's arable land. The system is based on the familiar use of nitrogen-fixing legumes to boost soil fertility. Instead of clovers or alfalfa the system uses nitrogen-fixing trees like the pigeon pea, Cajanus cajan, Gliricidia sepium (picture right by Wibowo Djatmiko) and the apple-ring acacia, Faidherbia albida. More

Phytophthora lateralis found in Devon
The first outbreak in England of Phytophthora lateralis has been confirmed on Lawson's cypress at an industrial site in the southwest. There have been previous outbreaks in Scotland and Northern Ireland, as well as in the Netherlands and France. Phytophthora lateralis causes an often fatal disease of trees, mainly in the genus Chamaecyparis. Lawson's cypress (C. lawsoniana) is the primary host, other potential hosts include the Pacific Yew (Taxus brevifolia) and White Cedar (Thuja occidentalis). The infection is thought to have been introduced several years ago and an investigation is underway aimed at identifying the cause of the outbreak.

Protein tags that measure light
Plant movement in response to light, phototropism, is controlled by a series of molecular-level signals between proteins inside and between plant cells. University of Missouri scientists report for the first time the role a critical protein plays in this molecular signalling pathway. Directional light is sensed through the action of two light-sensing proteins, phototropin 1 and phototropin 2. These proteins initiate the phototropic signalling response in conjunction with a third protein, called NPH3. Using a combination of genetic and biochemical methods, the scientists found that NPH3 functions as part of a protein complex that modifies phototropin 1 by adding a small protein 'tag' called ubiquitin. Either a single ubiquitin or a chain of ubiquitin proteins is added, depending on the amount of light the plant 'sees.' More

The return of 2-4-D
Dean Riechers of the University of Illinois and his team suggest that tank-mixing auxinic herbicides with glyphosate may be the best short-term option available to farmers interested in broad-spectrum, post-emergence weed control. 'Resistance has become a big problem,' Riechers said. 'In 1997, researchers predicted that glyphosate resistance would not be a big issue in Round-Up Ready crops. For the most part, they were right. But they underestimated a few weed species and resistance mechanisms.' Since the 1950s, 29 auxin-resistant weed species have been discovered worldwide. In comparison, 21 glyphosate-resistant weed species have been discovered since 1996 when Round-Up Ready soybeans were commercialised. Interestingly enough, two of the most problematic weeds in Round-Up Ready soybean and cotton, common waterhemp (Amaranthus tuberculatus) and Palmer amaranth (Amaranthus palmeri) are not yet on the list of auxin-resistant weeds. More

Is chlorophyll decomposition misunderstood?
A team at the University of Innsbruck have discovered a previously unknown chlorophyll decomposition product in the leaves of Norway maples. The different spatial arrangement of its atoms is indicative of a different decomposition pathway than those of other deciduous trees. In the autumn, deciduous trees reabsorb critical nutrients, such as nitrogen and minerals, from their leaves. This releases the chlorophyll from the proteins that normally bind it.

However, chlorophyll is phototoxic in this free form, and can damage the tree when exposed to light. It must therefore be 'detoxified' by decomposition. Various colourless tetrapyrroles, molecules with a framework of four nitrogen-containing five-membered carbon rings, accumulate in the dying leaves of higher plants, and have been classified as decomposition products of chlorophyll.

This premise is beginning to get a little shaky. The current study found none of the typical breakdown products in yellow-green or yellow Norway maple leaves. Instead, the main product found was a dioxobilane, which resembles a chlorophyll breakdown product found in barley leaves. There is clearly a chlorophyll breakdown pathway occurring in Norway maple leaves that differs from those previously known. The structure of this newly discovered dioxobilane is reminiscent of bile pigments, which are products of the breakdown of blood heme. This supports the idea that chlorophyll breakdown is not only a detoxification process; the resulting decomposition products could also play a physiological role (picture by FlickrLickr). More

Early Detection of Plant Disease
Each year, plant viruses and fungal attacks lead to crop losses of up to 30 percent. That is why it is important to detect plant disease early on. Yet laboratory tests are expensive and often time-consuming. Researchers at the Fraunhofer Institute for Molecular Biology and Applied Ecology are now working on a new quick test that will provide the farmer a low-cost analysis in the field. At the heart of the test is a magnetic reader. The device has several excitation and detection coils arrayed in pairs.

The excitation coils generate a high- and low-frequency magnetic field, while the detection coils measure the resulting mixed field. If magnetic particles penetrate the field, the measuring signal is modified. The result is shown on a display, expressed in millivolts. This permits conclusions about the concentration of magnetic particles in the field. Researchers are making use of this mechanism to track down pathogens. What is detected is not the virus itself but the magnetic particles that bond with the virus particles. More

Smarter toxins help crops fight resistant pests
One of the most successful strategies in pest control is to endow crop plants with genes from the bacterium Bacillus thuringiensis, or Bt, which code for proteins that kill pests attempting to eat them. But insect pests are evolving resistance to Bt toxins, which threatens the continued success of this approach. A research team at the University of Arizona reports the discovery that a small modification of the toxins' structure overcomes the defences of some major pests that are resistant to the natural, unmodified Bt toxins.

Unlike conventional broad-spectrum insecticides, Bt toxins kill only a narrow range of species because their potency is determined by a highly specific binding interaction with receptors on the surface of the insects' gut cells. Resistance occurs when these receptors are modified by mutation. A simple modification of the Bt gene enables the BT toxin to by-pass these receptors and thus the resistance. More

Weevils tackle the invasive water fern Azolla
The fast-growing water fern, Azolla filiculoides, can rapidly become a major nuisance in ponds and waterways. It forms a dense mat on the surface of the water, depriving other plants, fish and invertebrates of light and oxygen. A recent outbreak has covered a 2.5 mile (4km) stretch of the River Till near Lincoln. The Environment Agency is using the azolla weevil, Stenopelmus rufinasus, to control this outbreak. The weevil feeds off the Azolla without harming native species. The Environment Agency put 8,000 weevils in at this particular site and in a couple of weeks they will go up to millions of weevils, more than enough to control the amount of weed in the river. More

New study shows how trees clean the air in London
New research by scientists at the University of Southampton has shown how London's trees can improve air quality by filtering out pollution particulates, which are damaging to human health. They show that the trees of the Greater London Authority (GLA) area remove somewhere between 850 and 2000 tonnes of particulate pollution (PM10) from the air every year. An important development in this research is that the methodology allows the prediction of how much pollution will be removed in the future as the climate and pollution emissions change.

The work shows the real benefits of the planned increase in the number of street trees in London and throughout England, including the GLA's plan to increase the area of urban trees by 2050 and the UK government's 'Big tree plant' initiative. They found that by targeting tree planting in the most polluted areas of the GLA area and particularly the use of a mixture of trees, including evergreens such as pines and evergreen oak, would have the greatest benefit to future air quality in terms of PM10 removal. (picture by Cmglee)

New product for Phytophthora prevention
PlantTrust, a groundbreaking new product providing improved and cost-effective Phytophthora prevention and improved crop quality, has been unveiled by Everris (formerly Scotts Professional). PlantTrust employs an breakthrough platform technology - Controlled Release Control (CRC). This new advanced coating system provides gradual, steady and complete diffusion of the active ingredient - in this case Fosethyl Aluminium - into the substrate. The active ingredient is coated on to NPK fertiliser granules. Each PlantTrust granule controls the release of both fungicide and fertiliser ensuring the plant has exactly what it needs providing five months protection against Phytophthora cinnamomi, while feeding the crop for 2-3 months. More

New insight into plant immune defences
Plants are under constant attack from disease-causing organisms and to protect themselves they have developed a simple immune system. One defence mechanism is to trigger threatened cells to die and so remove the food source from the invading pathogen. Professor Gary Loake and his team at the University of Edinburgh have uncovered what is happening inside the cells to control this process and the role of the enzyme NADPH oxidase. Plants generate a short, sharp shock that kills off the cells around where the pathogen is trying to invade and essentially starves it out.

But somehow the plant must make sure that the effect is limited to that area. When a plant is attacked one of the common responses is to trigger the production of nitric oxide (NO) and a class of molecules known as 'reactive oxygen intermediates' (ROIs), which includes things like hydrogen peroxide and 'free radicals'. The team has found that there is a feedback loop where, as the levels of NO go up, NADPH oxidase is altered by the addition of an NO molecule to its structure so that it doesn't work so well. This causes the level of ROIs to drop and cell death tails off.

Defeating nematode worms with GM bananas
Banana is the most severely nematode damaged crop worldwide and commercial plantations use pesticides for their control. These can be environmentally damaging and cause health problems for agricultural workers. Moreover, these chemicals are too expensive for small-scale subsistence farmers in Africa where losses are most acutely felt. Now two safe technologies developed in the UK for potatoes are being used to control the nematodes and eliminate the yield losses.

The initial technology was developed at the University of Leeds and the novel genes transferred into plantain at the International Institute of Tropical Agriculture (IITA). Leeds and IITA together have shown that the technology is effective and a GM field trial is now planned for 2012. If trials are successful uptake could be rapid as the majority of banana consumers in Africa live in countries that favour deployment of [GM] plant biotechnology.

British research leads to UK launch of Beneforté broccoli
A new variety of broccoli with higher levels of a key phytonutrient is now available in UK shops thanks to experts working on both the biology of plants and the link between human nutrition and health. The new broccoli, which will be known as Beneforté, was developed at the Institute of Food Research and the John Innes Centre. The researchers used conventional breeding techniques to develop the new broccoli, which contains two to three times the level of the phytonutrient glucoraphanin than standard broccoli. Glucoraphanin is a beneficial chemical that is found naturally in broccoli and is thought to help explain the link between eating broccoli and lower rates of heart disease and some forms of cancer. Glucoraphanin also leads to a boost in the body's antioxidant enzyme levels.

Quotes of the Month

'If a cluttered desk signs a cluttered mind, of what, then, is an empty desk a sign?'

Albert Einstein

Events Calendar

Hortifair
1 - 4 Nov, Amsterdam RAI
Amsterdam, The Netherlands

Scotsturf
2 - 3 Nov, Institute of Groundsmanship
Edinburgh, UK

Postharvest and Quality Management of Horticultural Products of Interest for Tropical Regions
2 - 4 Nov, International Society for Horticultural Science
Bogota, Colombia

Pyrethrum, The Natural Insecticide
2 - 4 Nov, International Society for Horticultural Science
Hobart, Australia

Plants in a chemical world
7 Nov, Oxford Botanic Garden
Oxford, UK

Southern Growers Exhibition
9 Nov, Southern Growers
Chichester, UK

GM crops - where do we go from here?
14 Nov, Oxford Botanic Garden
Oxford, UK

International Symposium on Tropical Wines
14 - 16 Nov, International Society for Horticultural Science
Chiang Mai, Thailand

World Fruit and Vegetable Expo
16 - 17 Nov, WVF Expo
London, UK

Management of Tuta absoluta
16 - 18 Nov, EPPO/IOBC/FAO/NEPPO
Agadir, Morocco

Onion and Carrot Conference
16 - 17 Nov, Processed Vegetables Growers' Association
Peterborough, UK

Epigenetics and Tomato Improvement
17 Nov, Society of Biology
Sutton Bonnington, UK

Medicinal and Aromatic Plants
20 - 23 Nov, International Society for Horticultural Science
Antigua, Guatemala

Achieving food security and sustainability for 9 billion
21 Nov, Oxford Botanic Garden
Oxford, UK

Symposium on New Floricultural Crops
22 - 25 Nov, International Society for Horticultural Science
Buenos Aires, Argentina

IAgrM BIAC National Conference
23 Nov, British Institute of Agricultural Consultants
Details to Follow

Trees - A cut above the rest
24 Nov, Oxford Botanic Garden
Oxford, UK

Frontiers of Citrus
27 - 30 Nov, International Society for Horticultural Science
Tel Aviv, Israel

Solanaceae and Cucurbitaceae Joint Conference
28 Nov - 2 Dec
Kobe, Japan

Biopesticide International Conference
28 - 30 Nov, Journal of Biopesticides
Palayamkottai, India

Biopesticides
29 Nov, Association of Applied Biologists
Marston, UK

Advances in Biological Control
30 Nov, Association of Applied Biologists
Marston, UK

National Landscape Awards
2 Dec, British Association of Landscape Industries
London, UK

Quality Management in Supply Chains of Ornamentals
3 - 6 Dec, International Society for Horticultural Science
Bangkok, Thailand

Postharvest Quality Management of Root and Tuber Crops
3 - 6 Dec, International Society for Horticultural Science
Bangkok, Thailand

Postharvest Pest and Disease Management in Exporting Horticultural Crops
3 - 6 Dec, International Society for Horticultural Science
Bangkok, Thailand

Quality Management in Postharvest Systems
3 - 6 Dec, International Society for Horticultural Science
Bangkok, Thailand

Cashew Nut
9 - 12 Dec, International Society for Horticultural Science
Madurai, India

Vegetable Nutrition and Fertilization: Vegetable Farms Management Strategies for Eco-Sustainable Development
19 - 22 Dec, International Society for Horticultural Science
Giza, Egypt

International Symposium on Orchids and Ornamental Plants
9 - 13 Jan, International Society for Horticultural Science
Chiang Mai, Thailand

International Advances in Pesticide Application
10 - 12 Jan, Association of Applied Biologists
Wageningen, The Netherlands

All Africa Horticultural Congress
15 - 20 Jan, International Society for Horticultural Science
Skukuza, South Africa

Brassica Growers Association Conference and Exhibition
17 Jan, Brassica Growers Association
Grange-de-Lings, UK

New research into plant colour production
19 Jan, Bristol Botanic Garden
Bristol, UK

Harrogate Week
22 - 26 Jan, British and International Golf Greenkeepers Association
Harrogate, UK

International Symposium on Banana
23 - 26 Jan, International Society for Horticultural Science
Chiang Mai, Thailand

A Garden for a Thousand Years
26 Jan, Oxford Botanic Garden
Oxford, UK

If you would like to advertise a forthcoming event please contact. zoe.daniel@soci.org

Horticulture Group Contact Details

For submitting ideas or to volunteer to be part of a committee or a group, please contact:

Chairman - Peter Grimbly
Meetings Secretary - Marion Stainton
Minutes Secretary - Margaret Waddy
Newsletter Co-ordinator - Sue Grimbly, E: scihortigroup@btinternet.com
Group Coordinator - Zoe Daniel zoe.daniel@soci.org T: +44 (0)20 7598 1594