This article was originally published on the web at fuchsiaclark. pwp. blueyonder. co. uk, however that website is defunct at December 2016. The copyright remains with the original author(s).

Fuchsia pests and diseases

With regard to pests and diseases the fuchsia, contrary to popular belief, has relatively few problems in comparison to other species of plants. It must rate as one of the easiest to grow providing a profusion of flowers throughout the summer. It is virtually virus free and only susceptible to three main fungal diseases, rust, botrytis and sooty mould each of these will be identified and discussed a little later in the chapter. In addition to the fungal diseases there are of course several pests to be concerned about. These are whitefly, red spider mite and aphids, mainly greenfly. There are others of course which will cause concern but to a much lesser degree. These, mainly in the garden, are thrips, capsid bug and caterpillars. The other adversary is the vine weevil, the eradication of this pest will be deal with later in the chapter.

I would also profess that apart from botrytis most of the other pests and diseases are, except on rare occasions when buying plants from a specialist nursery, introduced unwittingly when buying or being given infected stock. Once introduced into the confines of a greenhouse or conservatory control is extremely difficult, eradication almost impossible, unless that is, you are able to meticulously follow the system I have used for many years, The 'Hot Water' treatment, this will totally destroy all adult insects, mites and their eggs that infest your plants. It will also destroy fungi spores giving freedom from rust.

The merits of using the 'Hot Water' treatment will be fully discussed and explained a little later in this chapter.

The various methods advocated for the control of pests and diseases is in the use of chemicals. The application has changed very little over the decades, but what is changing are the chemicals used in the manufacture of insecticides and fungicides. Almost annually, new formulae are discovered for the control of one insect or another only to be withdrawn from the market a short time later for various reasons including public health. When mixed with compost these chemicals were ingested through the skin and proved to be persistent, building up in the body to dangerous proportions. When using insecticides and fungicides take very stringent precautions to protect yourself and follow the manufacturers instructions to the letter. Be aware there is no such thing as a safe insecticide or fungicide and indiscriminate use will poison the plant, the environment and you, the user.

There are three methods of application which are:

A] Spraying.   B]Fumigation.   C] Systemically.

I shall deal with each in turn.

Spraying.

Application can be by means of a small one litre plastic bottle which incorporates a trigger spray. These can be purchased very cheaply and are ready for use. They are for spot spraying on an odd house plant to control a small outbreak of greenfly. For use in a conservatory or greenhouse where large numbers of plants are involved a more powerful pressure spray is required.

When using chemicals in liquid form always wear heavy duty not household protective gloves. Most of these chemicals are spirit based and can quickly degrade inferior gloves allowing the spray to contact your skin. With powder based chemicals handle them very slowly whether opening a sachet or using a measure. Quick movements can disperse the fine particles to atmosphere, hence the need to use a facial mask. When spraying in the greenhouse note the air movement and turn off any circulating fans. Always walk backwards away from the spray. With large plants it is difficult to ensure complete saturation. Place two pieces of wood across the benches then turn the plant upside down supporting it by the root ball. [See photo]

The spray can then be directed downwards allowing the surplus residue to drip to the floor. When upturning the plant shake off any further surplus spray to prevent it from dripping onto the root ball damaging the roots. This is a prime cause of plant failure, especially show plants where the chemicals have damaged the microscopic feeding roots hence inhibiting growth. Although the plant will survive, it will not grow or flower as anticipated. The first signs are the lack of lustre on the leaves. If this occurs knock the plant out of its pot and examine the root ball. If the tiny feeding roots have all turned brown suspect chemical poisoning. These symptoms are very often wrongly attributed to over watering, root compaction or excessive acidity through over feeding because the damage will have occurred progressively during the previous two weeks and will not be associated with spraying. Plants damaged in this way have confounded many an expert and spoilt many an exhibitors dream.

In order to save a plant damaged as a result of any of the causes outlined above, remove it from its container and leave on an open bench until the compost dries out a little. Using a pointed cane or other instrument, tease away the outer compost to remove the damaged feeding roots and contaminated compost. Take care not to damage the larger perennial roots. Once most of the damaged roots have been removed, dip the root ball gently into a tub of warm water to dilute or wash away any surplus chemical residue. Allow the surplus water to drain away before dipping the root ball into fine or crushed perlite before re-potting into fresh compost. Do not water the plant for at least 24 hours and place it in a cool shaded place out of direct sunlight. It will not take long for the plant to recover if watered sparingly with warm water. Do not feed.

Fumigation.

Not a method to be used by the amateur I deem it too dangerous and have never found it completely successful. A number of fumigants have been removed from the market, one in particular, Nicotine Shreds was extremely difficult to ignite unless tinder dry. Once lit, the greenhouse was out of bounds for at least 24 hours. This is one method of control I would not recommend under any circumstances. It is for professional nurserymen only.

Systemically.

This method of applying insecticides/fungicides is all too often confused by the novice and amateur misinterpreting the word 'Systemic' when printed on a packet or container. The manufacturers instructions must be read and fully understood before use. The term Systemic as used in horticulture implies ingestion through tissue rendering the plant toxic to browsing insect or to inhibit the germination of fungus spores. There are two methods of application for ingestion by the plant, through the root system by watering the chemicals into the compost or soil or by spraying the chemicals onto the underside of the leaves to be ingested via the stomata cells. My reading and research on this particular method indicate that air temperature is the criteria critical for this method to be successful. The chemicals should be diluted using warm water, between 20 to 25 deg C. applied either by dipping or spraying the plants. Air temperature influences the degree of opening of the stomata cells on the underside of the leaf through which carbon dioxide and other substances can be absorbed. The ambient air temperature for best results are in the region of 15 deg C and above. If sprayed or dipped at lower temperatures the degree of success will be minimal. As the temperature drops the stomata cells start to close leaving the chemical solution to slowly evaporate. A complete waste of time and effort. To digress slightly, an understanding of these principals are also paramount if foliar feeding is to be considered. Unless the temperatures are correct it is a virtual waste of time except for the residue dripping onto the compost.

Identifying the various insects and fungus diseases is not easy.

The scourge of the fuchsia is the whitefly and red spider mite both of which are extremely difficult to eradicate.

Whitefly		Red Spider Mite eggs and damage
Aphid - greenfly

The whitefly, being so tiny, is difficult to identify by the novice and amateur grower. It is often confused with dead carcasses of greenfly lying on top of a leaf. Whitefly, consistent with other insects always reside on the underside of the leaves. This is where they extract their nutrition from the stomata cells to the detriment of the plant. The whitefly was one of the most difficult insects I had to photograph. They are so tiny, damage easily and move quickly once disturbed. I wasted a lot of time and film trying to shoot the film above. I eventually hit on a solution that provided the answer. I collected a leaf from a laburnum tree which I knew to be infested with both whitefly and red spider. I placed the leaf into a small box then put it into the freezer. Within thirty minutes I had the perfect specimen, lying on its back exposing the whole underside of the insect. It was not until I viewed the slide film slide did I realise the whitefly had burgundy eyes, two antennae, two pair of wings and a golden and burgundy abdomen. It also had a long pointed snout. I was also unaware of the eggs lying close by.

Red Spider. This is not a spider in the real sense but a tiny mite that weaves a very fine web to protect its young, hence the misnomer. It is often confused with a very tiny red spider which gathers in huge numbers on the underside of leaves for mating purposes. These do not harm the plant in any way. The second photo illustrates the damage done to the leaf by red spider mites. The white dots in the centre are empty egg cases left behind after hatching. The mites have severely damaged the leaf by feeding and destroying the stomata cells. This is apparent from the brown blotches which are always adjacent to the centre spine of the leaf. The mites have since moved to fresh leaves higher up the plant. These red spider mites are so tiny they are barely visible to the naked eye. If your plants seem to be slow in developing and the bottom leaves are losing their lustre, turning brown as opposed to yellow, {A different symptom} suspect red spider mite. The easiest way to identify the mite is either with a powerful magnifying glass or by holding the plant up to the light where the leaf damage is obvious. If you have ever been a steward at a fuchsia show and wondered why the Judge holds a plant up to the light, this is what he is looking for. This is one insect that can over winter in the loose tissue of ripened wood. Hence the need for using the 'Hot Water' treatment which will eradicate it completely.

Greenfly. This little pest is always easy to identify and eradicate. Its numbers can easily be decimated by both the nymph and adult lady bird beetles. It usually confines its attack to one plant at a time and can be washed away with the spray from the garden hose. They can also be troublesome on freshly rooted cuttings in a warm greenhouse. Spray for control.

Thrips. A fast moving green insect, larger than a greenfly, which is very active in early spring. Its presence is rarely noticed until the damage is done. It attacks fuchsias mainly in the garden. It punctures the growing tip, [apical meristem] with its sharp snout. The damage is only obvious weeks later when you will notice the new leaves are distorted and blackened at the edges. The growing tip is also permanently damaged. This pest can virtually destroy a collection of show plants overnight. Keep an awareness for this pest in the early spring. Spray for control.

Caterpillars. These are a nuisance mainly in mid-summer to early autumn when tiny moths move into the greenhouse to lay eggs on the underside of the leaves. Once again their presence is only noticed when it is too late. The obvious signs of attack is the damage to the leaves. The damaged leaves can easily be removed without too much distress to the plant. However, there is one caterpillar from the Mediterranean area, now indigenous to the British Isles, with a voracious appetite. It can completely defoliate a fuchsia plant in several days and is the caterpillar of the Elephant Hawk Moth. They abound in various clumps of large weeds and are especially partial to rosebay willow herb, a close relative of the fuchsia I understand. The moth is very large with pale green and pink colouring. The caterpillar grows rapidly and looks very fierce. Children are loathe to handle it. If one is found browsing on one of your plants let it be. It will very quickly make its way down and pupate in the compost. It is a rare visitor to the greenhouse and fun for the children to see and appreciate.

Elephant Hawk Moth caterpillar browsing on one of my plants

Fungal Diseases.

There are three that are prevalent to fuchsias:

Botrytis cinerea, a grey mould fungus, most prevalent in the greenhouse environment attacking new growth and freshly rooted cuttings where the stems have not ripened. It attacks the epidermal skin preventing sap from rising thus causing the plant to succumb. Fluctuating temperatures and poor air circulation are ideal for its proliferation. Very easy to control, remove the causes.

Sooty mould, a fungus growing on the honeydew, a secretion from greenfly, on top of leaves. Causes little damage but is unsightly. Eradicating the greenfly will eliminate the problem. If required the leaves can be sponged with warm water.

Fuchsia Rust [Pucciniastrum epilobii] This is the scourge of the fuchsia world. It can be bought or given unwittingly on infected stock and once introduced is extremely difficult, if not impossible to eradicate.

The first signs are a slight discolouration to the top of the leaf. If examined more closely the underside of the leaf will have clusters of red orange pustules like small warts. Once the pustules ripen and change colour to brown they erupt and exhaust their spores to the atmosphere infecting every fuchsia in close proximity. There are several fungicides which will give a modicum of control but again eradication, once infected, is extremely difficult. Here again, the 'Hot Water' treatment is the answer. This particular fungus is rather a nasty one. During the growing season, especially during March, April and May, keep a sharp look out for the tell tale signs more especially on newly acquired stock. If rust is suspected, isolate the plant well away from your main stock. Remove any obviously affected leaves and destroy them. At this time of the year it would be more prudent, if possible, to dip the whole plant in a solution of fungicide then water the root ball with the remaining solution. Take care of course to read the manufacturers instructions, although in the past, I have used this method with varying degrees of success using different fungicides. Collect and destroy any fallen leaves whether infected or not. I have studied this fungus over a period of time and found it to be extremely virulent especially in the confines of a closed heated propagating frame. If your are an exhibitor and have exhibited plants in a flower show, never return them to the greenhouse/conservatory where your main stock is growing. Isolate and dip before returning them to their original growing environment.

The Vine Weevil

This insect has been the scourge of the fuchsia fraternity for many years. The photo below is to illustrate several points that distinguish the vine weevil from the normal garden beetles. The first thing to appreciate is the weevil is nocturnal, rarely seen during daylight unless disturbed from its hiding place. They vary in colour from jet black to mottled dark grey but the most significant difference is, unlike the garden beetle, the weevil can't run. If the photo below is studied carefully you can see by looking at the end of its legs, why it is unable to move quickly. Being nocturnal it does not need to move quickly to avoid predators. It is mainly vegetarian and spends most of the night browsing. If you look closely at end of its legs you will see it has a single sharp claw and a soft bulbous pad giving it the ability to scale any surface including glass. It does not like water and, as you can appreciate, is a very poor swimmer. The average gardener is mostly unaware of its presence, unable to read the tell tale signs as depicted by the second photograph, which is often mistaken for caterpillar damage. Once the damage is identified during daylight return to the plant several hours after the onset of darkness with a powerful torch. Examine the plants again very thoroughly and you will surely find the weevils browsing on new growth from where they can be hand picked and destroyed. They are quite difficult to remove with their claws firmly embedded in the soft leaf tissue.

Vine Weevil Adult		Typical Vine Weevil Damage

For the professional gardener and amateur plant exhibitors these insects, once established, can wreak havoc defacing both plants and flowers virtually overnight. The damage detracts from perfection which is heavily penalised by judges. However, this is only half the story.

Once this pest has established itself in your garden, greenhouse or conservatory it is extremely difficult to eradicate in so far as it will also have established itself in the neighbouring gardens. It is during the late summer early autumn when the weevil decides to proliferate by laying numerous eggs at the base of its favourite plant. These quickly hatch into tiny grubs, larvae similar in shape and size to fly maggots. The photograph below shows the larvae nestled in the compost. If these are not removed during the process of potting down, they transform into the actual weevil. During March and April, they start to develop the legs and anatomy of the weevil and then start to make their way to the surface of the compost/soil where the transformation continues with the hardening and colour change of their body. Unlike other grubs they do not pupate and form chrysalis.

It is not widely known that the Vine Weevil does not require a mate, they are all female. Once the eggs hatch they quickly start to feed on the root system starting with the tiny feeding roots then progressing to the larger perennial roots. They completely devour the outer tissue, permeable membrane, of the root effectively preventing osmosis from taking place. Osmosis is a muscular contraction of the tiny cells carrying diluted nutrients to various parts of the plant, mainly the leaves, for conversion by photosynthesis into sugars and starches for cell division, the method by which plants feed and grow. It is this soft membrane that the larvae adore. Once they have completely encircled the root or the main stem it effectively kills the plant through starvation. Plants, especially fuchsias, being over wintered in the greenhouse can be completely root pruned. Over wintered specimens that have been attacked can be lifted from the compost completely devoid of roots. Excluding dangerous commercial chemicals and the not too successful biological controls, there is now a solution to the problem in the form of a relatively new chemical, Imidacloprid.

For established pot plants apply imidacloprid as a liquid drench, ' Bio Provado Vine Weevil Killer '. Read the manufacturers instructions regarding dilution factors and protect exposed hands and arms using neoprene gloves. This is both a systemic and contact insecticide which, when watered into the soil or compost, gives protection against the grubs for up to six months or more. I have also tested imidacloprid as a spray against greenfly and red spider with considerable success. Provado is not cheap and if a large number of plants are to be treated it can prove expensive. Once you have established the presence of the weevil during the summer it is a waste of time and money to either spray or drench your plants too early. The best time is during late summer early autumn say September and October. At this time the eggs will be starting to hatch and the larvae most vulnerable. To date, Provado is my No.1 insecticide for general pest control. I have tested it on all manner of plants growing inside and outside my greenhouses, in containers and established plants in the garden with complete success. I have always been very sceptical regarding manufacturers claims for their products having found several which fall short of their claims but with Provado, Bio have the complete answer. Their written instructions should be followed implicitly and always wear protective clothing. See the article on potting down.

Hot Water Treatment

At this juncture, having dealt with Vine weevil, I will now explain in detail my method of treating plants using the 'Hot Water' method which, if meticulously followed, will eradicate all the other pests, fungi and other diseases which may have attacked your stock during the growing season. If these are not eradicated at the end of the season they will surely, not only destroy your plants, but your enjoyment next season. I have used this system for over thirty five years with complete success not only with fuchsias but all my other perennial plants grown in the conservatory and patio gardens. If in doubt about treating a different species of plant do a test on an individual plant first. If it is not suitable the plant will show its distaste within seven days.

When and where to start?

Start towards the end of the growing season, late September early October, when most fuchsias and other flowering plants are past their best, showing signs of wanting a long earned rest. The time when outdoor temperatures plummet to and below 5deg.C. The average temperature of your fridge during summer.

Take each plant individually and gently prune it by removing the flowering tips of each branch. This needs an explanation, not everyone will understand the term, 'gently prune'. All this means is the removal of the ends of the flowering branches back to the first pair of leaves before flowers appeared in the leaf axils. Examine each branch and look for a pair of leaves where there are two tiny dormant buds in the leaf axil. All the other leaf axils above will have scar tissue where the pedicel of the flower has been aborted. Some leaf axils may still have the pedicel and seed pod attached. Ignore these and prune off all of the stem above the leaf axils where the dormant buds are nestling. Once the first few branches have been pruned back the rest of the pruning is quite simple and straightforward. See photo below.

Pay no heed to the advice proffered by some of the older authors and speakers where the advice was to prune hard back with the onset of winter. Pruning, stopping and timing will be dealt with in a later chapter. Suffice to say that your plants require pruning twice. Once at this time and the final pruning in the following spring.

Once all the plants to be dipped have been pruned they must be moved outdoors and left for a minimum of three nights, longer if at all possible, to allow any pests or disease to acclimatise to the cold night temperatures. This is paramount if you are to be successful. Once all the plants have been removed from the shelter of the greenhouse or conservatory, their accommodation must the thoroughly cleaned. All the old debris, leaves and flowers must be removed and if possible washed down. I use a high pressure hose for this task after spreading a little Jeys Fluid around. This is one commodity I am never without. Unless this particular chore is done correctly you will be wasting your time. Once everywhere is shipshape close any roof vents that may be open. Leave only the side vents or windows open. The reason being, this is autumn and the leaves from surrounding trees will be blowing everywhere and will find their way into your greenhouse through an open roof vent. A percentage of these leaves will be infested with one insect or another, most probably red spider and or white fly. If the roof vents are required place some netting over them to prevent leaves blowing in. These guide lines lessons learned from mistakes I made early in my growing career.

When the preparations are finished and the plants have spent the requisite time outside, wait for a suitable day when the weather is dry and reasonably calm. This is when to start dipping, treating your plants.

For the next stage of the operation you will need the following items:

A] A water container large enough to accept the head of your largest plant. II use an old Burco Boiler purchased second hand many years ago. The beauty is, being electric, it is equipped with a heater and setting control.

B] A large thermometer.

C] One large sieve, to remove floating debris from the water.

D] A pair of neoprene or similar rubber type gauntlets. Not household plastic gloves.

E] Spare labels, pen and garden wire.

F] Access to a supply of hot water if your container is not equipped with its own heater. An old electric kettle will come in handy.

When the conditions are suitable make a very early start. As soon after dawn as possible whilst the air temperature is still quite cold. The importance of this will be explained a little later.

Start by filling the container preferably with hot water even if your container has a heating element , it will save waiting whilst it is heating up. Insert a large thermometer in the water and maintain a temperature between 112deg F to 118 deg F or 44 deg C to 48 deg C. Keep within these parameters for this treatment to be successful. Appreciate that the temperatures of 120 deg F 50 deg C is half boiling point at sea level. A plant immersed in water at this temperature will suffer tissue damage and may not recover.

Once the correct temperature has been reached it must be maintained, check it constantly. At this point it is optional whether to add a proprietary insecticide to the water. If added it must be strictly to the manufacturers dilution guidelines. For many years I used Sybol but it is no longer available but a good replacement would be Bio Provado which I have now used for two years. Note the temperature range on the thermometers below.

Once the water is ready it is time to start dipping your plants. If any plant is too large pull the head in using cellotape or garden twine to avoid damage. At this point I need to explain the importance of exposing the plants to the cold outside night temperatures which is the key to success. A high percentage of insects and diseases could possibly withstand a slow progressive rise in temperature to 118 deg f or 44 deg C, in the height of summer. A closed greenhouse in full sun during the summer can easily reach temperatures in excess of 112 deg F, 44 deg C and above with high humidity and the plants and all the pests will survive. How then does immersing plants at this temperature completely destroy not only the adult insects and fungus but the mites, eggs and spores? The answer is in the dramatic sudden change in temperature from just above freezing to near half boiling point in a fraction of as second. I doubt if a human could withstand this treatment let alone these tiny life forms. I don't recommend you try this at home!!!!

Using the protection of the gloves recommended, illustrated below, totally immerse the plant up to and including the top two centimetres of compost. Turn the plant slowly back and forth to a count of five seconds. Remove the plant from the water and allow the surplus water to drain back into the container. Once treated the plant must be returned to the shelter of the greenhouse or other accommodation away from the untreated plants to allow them to cool down. Check the water temperature after three or four plants have been immersed and if low, add additional hot water. The high temperatures must be maintained. If any plant has not been treated correctly you will have wasted your time and effort.

Debris from the plant and top of the compost will undoubtedly fall into the water. Clean it off with the sieve at intervals. A point of interest, this method is also used on chrysanthemum stools and begonia tubers to destroy eelworm and other pests. It is also used by some poultry farmers to remove feathers from slaughtered chickens ready for market. Once all the plants have been treated allow the water to cool for about an hour before using it to water the compost of all the treated plants. This, prior to potting down, will eradicate all the vine weevil and scarid fly larvae along with any other any other soil pests. It can also be used on other container or garden plants not being over wintered under cover.

Once the whole operation has been completed isolate them from any other plants unless they have been similarly treated. After several days a large percentage of the old leaves will start to turn yellow and drop off. Fuchsia, being deciduous, this is a natural phenomena. After a few days, I purposely try to defoliate as much of the plant as possible leaving just the tiny side shoots in the old leaf axils to develop during the winter to provide healthy cuttings in the spring. Spray the exposed ripe branches regularly with warm water to prevent dehydration. To every five litres of warm water add a level teaspoon of Magnesium Sulphate, an unrefined form of Epsom Salt. This is not only an excellent micro nutrient, it acts as a wetting agent allowing the water to soak into to the branch membrane, the epidermis, keeping it soft and supple. For many years and even today, dehydration is referred to as 'die back' by many prominent experts and thought to be some kind of disease or genetic disorder associated with fuchsias. This is not so. Quite simply it is brought on by the slow dehydration, drying out, of the ripened branches due to warm dry conditions. As this dehydration moves progressively towards the roots it kills the tiny dormant buds in the old leaf axils. Pruning plants back too hard in the autumn and early winter can induce it thereby disfiguring an otherwise perfect plant. Root pruning by vine weevil can also be a factor. Look carefully at the two plants below, both in 3.5" - 9cm pots. This is the framework achieved using my propagation methods described in the chapter 'Methods of Propagation'.

Ensure that your over wintering plants are sprayed at least twice a week to reduce dehydration to a minimum. This is also a good time to look at the plants structure whilst there are no leaves to obscure your view of the framework. Using strong garden wire pull any wayward branches back into the symmetry to maintain the overall shape. After a few months, the branch will fully ripen into its new position and the wires can be removed. A valid tip for the budding show person looking for perfection.

The next stage in this sequence of 'The Fuchsia Year' is repotting and potting down.