Christmas at the Botanics Bug Wars Scottish Plant Lore
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ISSUE 72 | AUTUMN 2018 Christmas at the Botanics The magical, botanical, illuminated trail Bug wars Biological control at RBGE Scottish Plant Lore Scotland’s flora through the centuries 2 | THE BOTANICS 72 AUTUMN 2018 Contents Foreword In this issue... A visit to any one of our four Gardens this autumn will perhaps 4 Christmas at the mean dierent things to dierent Botanics visitors. This may range from 6 Bug wars: Biological enjoying a pleasant relaxing walk control at RBGE through to actively studying the biodiversity of plants and 6 | THE BOTANICS 72 AUTUMN 2018 THE BOTANICS 72 AUTUMN 2018 | 7 Since the 1920s, there has been based and can kill o our native everything in between. In an Below: Larva of Australian Ladybird (Cryptolaemus montrouzieri) significant research on using natural non-pest insects at the same time. (centre le, with long legs) devouring mealy bug. enemies to control glasshouse pests. The pests we are currently battling One of the first of these was the with in our Glasshouses include Red parasitic wasp Encarsia formosa used Spider Mite, with the introduction of the to control glasshouse whitefly, and now predatory mites Phytoseiulus persimilis. widely used commercially on tomatoes We are also eectively controlling whitefly increasingly busy world, the and other horticultural crops. with the regular introduction of the The use of non-native predators has parasitic wasp Encarsia formosa. To fulfil Bug to be comprehensively studied before their lifecycle in their natural environment, they are approved to ensure that they do these wasps must lay their eggs into the not have a wider impact than intended; nymph stage of the whitefly. The wasp in reality this could mean a negative larvae develop inside and parasitise the influence on their new environment. whitefly, subsequently emerging as a Above: Parasitised whitefly scales; each black scale contains a developing Encarsia formosa wasp. value and solace that people gain For example, the cane toad was wasp – and so the cycle begins again. introduced to Australia in 1935, from Mealybugs are being consumed in large in some of our glasshouses and can be its native habitat of South and Central numbers by Cryptolaemus montrouzieri dicult to control as the caterpillars ‘sew’ America, to control the cane beetle, (Australian ladybird) predators, which themselves inside leaves; so we are using wars damaging sugarcane crops. However we release in the larval stage. If you look the natural bacteria Bacillus thuringiensis Biological control at RBGE with no natural predators, and the fact very closely you might be able to see to control the emerging caterpillars in their that its toxic skin eectively poisoned some in action. We are also trying to feeding stage. We are also using dierent from being in a garden and being hroughout history, humans Over the past few months, visitors to the glasshouses may have anything that tried to eat it, numbers control the scale insect present in the microscopic nematodes to control sciarid Diaspis boisduvalii have practised biological noticed many of our plants ‘decorated’ with small cards and sachets increased dramatically without control glasshouses, , with the flies, vine weevils and slugs, and these are Tcontrol, using one organism and created a whole new pest problem introduction of Rhyzobius lophanthae applied as a drench. to control the numbers of another. of varying shapes and sizes. So what do these envelopes contain? that persists to this day. predatory beetles. This has been our Increasingly, these products are For example, the Egyptians were most Once approved for use, these biggest challenge so far, as many scale available for home use and can be likely the first civilisation who learned to grow healthy strong plants: pests under glass. However, increasing biological control agents are insects are very well protected by a purchased in garden centres and online. the benefits of this approach, using the healthier the plant, the more awareness of the wider environmental environmentally friendly, with no protective ‘shell’ that they form around The key to ensuring the successful able to work with plants is now cats to control the mice and rats raiding resistant it is to pests and diseases. impacts of pesticide use has led to resistance build up, and there are not themselves. Even the giant Victoria introduction of all these bio-controls is their supplies of stored grain. Our aim However as any gardener knows, pests more investment into the application the same health and safety concerns waterlilies are not immune to attack to know what pest you have, so you can at RBGE is to control our pests, albeit by their very nature can be dicult to of natural non-native enemies and as with pesticide use. Biological control from aphids, and a multi-aphid parasite target it with the correct product and on a much smaller scale, using bugs control. Physical removal methods are ‘beneficial’ insects (bio-control) in the is much more targeted to the specific is being introduced directly onto the lily apply at the correct time. Keep plants to control other bugs. This is a battle always considered in the first instance, controlled glasshouse environment. pest; many pesticides are very broad pads. Tortrix moth can also be a problem in good health, because they are more of miniature with chemical susceptible to attack if stressed. proportions! Our aim at RBGE is to control only Careful monitoring is essential to keep recognised as being extremely To explain this used as a last on top of the problem. in more detail, control our pests, albeit resort. At RBGE, At RBGE we want this approach to we first need to on a much smaller we have been work. We accept that it is impossible look at some of scale, using bugs to using bio-control to eliminate every single pest here, and the challenges products in actually we need a small number of pests faced by RBGE’s control other bugs. specific areas of to keep our beneficial populations going horticultural This is a battle of the Garden for and growing! Our aim is to control them important to our health and well- team in growing miniature proportions! many years, but to a manageable amount whilst making plants in artificial this year, for the sure that all of our plants remain as environments. first time, we healthy as possible. The goal of our Within the glasshouses at RBGE, are trialling pesticide-free control in our pest management system is to reduce an amazing number and variety of public display glasshouses. and, if possible eliminate, the use species are cultivated from all over The use of pesticides raises a number of pesticides in our public display the world, some of which are incredibly of issues, and our main concern is glasshouses. This will inevitably take being. As horticulturists, we are rare and endangered. the environmental impacts. Another more time and eort to control our pests Unfortunately many of these plants important issue is the potential for but will ultimately help to ensure a safer are susceptible to pests that, up until the pest to build up resistance to the and more pleasant environment for all. reasonably recently, could only really be formulation of a pesticide. With ever eectively controlled with the use of more stringent legislation, there are Left: Louise and Pat monitoring pest numbers on the giant Victoria waterlilies and applying pesticides. We always do our very best now fewer products available to control bio-control directly to aphid colonies. extremely fortunate that our work in nurturing the plant collections Schools in the Cottage and garden landscapes is enjoyed and can mean so much, to so many 10 Autumn colour at visitors, on many dierent levels: both here in Scotland and across Benmore from actively engaging school and the globe, we need to be able to 10 Non-stop sunshine at community groups with plants, transfer the horticultural skills and Logan to oering an award-winning knowledge gained over many years. Edinburgh Festival venue. We are extremely grateful to the 11 Developments at However, we are all currently funding support for horticultural Dawyck enjoying the work and vision apprentices at Benmore and of previous generations of Edinburgh to take the first steps in 12 The Pianodrome lands horticulturists, and a key future this process. at the Botanics challenge for the RBGE horticultural I do hope you not only enjoy this 12 | THE BOTANICS 72 AUTUMN 2018 THE BOTANICS 72 AUTUMN 2018 | 13 team will be attracting the next issue of the Botanics but also take Right: The Pianodrome was designed and built by a team of more than 100 people, many of them volunteers, o site. It was then dismantled and rebuilt in the Botanic Garden. The Pianodrome is a 100-seater auditorium created from 50 generation with the skills and the opportunity this autumn to discarded pianos. Well-seasoned timbers have a resonance that, when combined with the gentle reverberation of taught knowledge to help cultivate the strings attached to old piano visit each and every one of our four soundboards, creates a unique acoustic environment. This results in the whole structure becoming a gigantic instrument that both 13,500 species and 130,000 musicians and an audience can gardens and help support the work immerse themselves inside. art-installation, part-concert- venue, part-sound-lab, the PPianodrome defies all definition, but probably the most remarkable thing plants, and manage RBGE’s four of RBGE. about this whole project is the leading Le and above: The Pianodrome was housed in lights behind it. Tim Vincent-Smith the Botanic Garden under a geodesic dome supplied and Matt Wright are not designers, by Atlas Domes of Eddleston.