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At the Royal Botanic Garden Edinburgh (RBGE), Supervisor Louise Galloway is in the process of planning her next overseas
plant collecting expedition to collect rare Vireya Rhododendrons from South-East Asia. She recalls a time five years ago;
when she watched helplessly whilst her beloved recently rooted cuttings succumbed to Vine Weevil.
Looking at the sick plants a colleague, who knew of Becker Underwood’s work, told her about Nemasys Vine Weevil Killer
and Louise has not looked back since. “I spent so much time propagating the cuttings,” said Louise, “that I was really
upset when I lost the lot to vine weevil. We no longer have a problem because we now use Nemasys Vine Weevil Killer twice
a year, in the spring and autumn.”
“I find the instructions on the packaging extremely easy to understand, the Becker Underwood pie chart is excellent as it
explains the lifecycle of the Vine Weevil and therefore tells you exactly when to target the pest, the website is very
user friendly too!”
Particularly loving the Vireyas, Louise knows how devastating it can be to lose them to pests. Vine Weevil have a
particular liking for Rhododendrons. The plants that Louise looks after are slow growing and have very fine surface roots
susceptible to damage therefore it is very important to protect them. Louise is responsible for the world’s largest
collection of Vireya Rhododendrons. Starting with only and handful of plants in the 1950’s, through expeditions and
collaboration with the scientific and horticultural staff in Edinburgh and overseas, the RBGE now hold approximately 165
out of the known 300 species of Vireyas, in total 2,672 plants to protect!
Louise started her career in horticulture when she was a Saturday girl in the RBGE’s visitors’ shop. Her love of the
plants that she was surrounded with encouraged her into full time horticulture; with on the job experience and day
release she gained SVQs in Amenity Horticulture, later achieving an HND in Horticulture with Plantmanship on the full
time course at the Garden. Louise has a particular interest in Integrated Pest Management and now she is a qualified
BASIS pesticide advisor she is able to advise staff throughout the garden on pest control with more and more of a
leaning to biological control.
At Edinburgh Botanical Gardens there are 10 public display glasshouses and over 20 behind the scenes research and
propagation houses, nearly two acres in total. Louise is responsible for the pest control under glass and she uses
nematodes wherever possible, using brand leader Nemaslug as an effective treatment against slugs especially in the Fern
House, and Nemasys for sciarid flies which can be a problem in the propagation areas.
“New 5 degree Nemasys Vine Weevil Killer is much more tolerant of the Scottish climate,” continues Louise, “and I will
keep using nematodes because I know they work. We grow many rare and endangered plants here in Edinburgh and I want to
make sure they stay as healthy as possible. With so many areas in the world lost to mans’ endeavours, we are the
custodians of a priceless plant collection and I feel very privileged to work here.”
[top]
The lifecycle of a Vine Weevil
Gardening is a popular pastime and massive numbers of container plants are produced yearly. However, many of the
insecticides used by commercial growers have been banned, such as aldrin which disappeared in 1989. Although this is
great news environmentally, vine weevil numbers have risen exponentially as a result and they've become a problem in many
gardens. And, as a native pest, they're always going to be around!
You can tell if you've got vine weevils because the adults eat characteristic circular notches in the edges of leaves,
usually choosing healthy evergreen plants. Although the damage looks awful, it's merely cosmetic - the serious damage is
happening underground where the larvae are active. These feed rapaciously on the roots, eventually causing the death of
the plant. If your plants are wilting as if they're dry, but the soil is moist, then give the leaves a gentle tug. If the
whole plant comes away in your hand, you may find that vine weevil larvae have eaten the roots. Many plants are affected,
especially those with fibrous root systems such as sedums, primulas and fuchsias. However, all containerised plants should
be checked regularly.
The most effective way of controlling the pest is by killing the larval stage - and to be successful at this, you need to
be aware of the life cycle. You can't kill the adults using insecticides and, being largely nocturnal, they're hard to see
unless you go out at night with a flashlight and pick them off by hand, then stamp on them hard - a satisfying sound! The
only stage you can kill easily is the larval stage.
One of the main problems is that all vine weevil adults are female and each produces hundreds of eggs parthenogenetically
ie without a mate. The eggs hatch to produce 'C' shaped, legless, larvae with a distinctive brown head - these feed
throughout late summer and autumn. During winter their feeding activity decreases as they move down into the ground, but
in spring they start feeding again. So the best time to treat the soil or compost is during the autumn, when the soil is
moist and above 5C. If the problem isn't severe, then treating the garden now should be adequate. However, you can also
treat during spring if the problem's severe.
Using a naturally-occurring nematode worm, Nemasys Vine Weevil Killer is the most effective way of controlling the pest
and is safe for children, pest and wildlife. The nematodes seek out the larvae and enter through natural body openings.
Once inside, they release bacteria that prevent the pest from feeding and it dies. The nematodes reproduce inside the
dead pest and release a new generation of hungry infective nematodes, which disperse and search for further prey.
Simply add the powder to a large bucket of water and mix thoroughly, then dilute it according to the instructions. Using
a watering can with a coarse rose or a hose-end feeder such as that produced by Miracle-Gro or Photrogen, water it on to
moist soil around the affected plants. Try to apply it during the evening to prevent it drying out and ensure the soil
remains wet so that the nematodes can move through the soil solution to find the larvae.
Bio® is a registered trademark of Bayer Crop Science. Slug Clear™ is a trademark of The Scotts Company and its
affiliates. Provado® is a registered trademark of Bayer AG. doff™ Slug Killer is a trade mark of Doff.
[top]
Biocontrol of Vine Weevils in a cold climate
Simon Piggott, Becker Underwood, Littlehampton, UK & David Chandler, HRI Wellesbourne, UK.
Introduction
The Black vine weevil (BVW) is one of the major pest problems for growers of annual and perennial ornamentals and soft fruits. The characteristic notching around leaf edges is made by adult weevil feeding, but most economic damage is caused by larvae feeding on roots which in severe infestations cause the death of the plant. Many growers who have opted for the use of nematode biological control have found that soil temperatures can limit the use of currently available products. Such products are restricted to use in temperatures above 12oC and the application window is usually closed between mid-autumn to mid-spring. Nematodes
Entomopathogenic nematodes (EPN) are generally drenched onto compost or soil for the control of vine weevil during the autumn and again in the spring but with the restriction of a minimum of 12 oC. However, research during the early 90s by scientists at HRI led to the discovery of a new nematode isolate that was adapted to colder conditions. The HRI Project
Discovery
In 1990/91 a new nematode isolate (Steinernema kraussei) was found in Scotland that was able to infect and kill black vine weevil larvae at low temperatures. It was found that when tested at a temperature of 6oC (a temperature where commercial products are practically inactive) control was excellent but it was also found to be as good as commercial products at warmer temperatures. This is important as the isolate was shown to be suitable to replace existing nematode products. Further assessments were therefore carried out under more practical field situations. Field trials
When compared for 14 weeks from December to March with a commercial product against black vine weevil in field conditions, soils temperatures at a 10cm depth ran at an average of 2.7 oC (-1.5 to 7.3 oC). It was found that, as expected, the commercial product failed to significantly control BVW at such low temperatures. The new isolate killed up to 81% of the larvae (Fig.1) and, unlike the commercial nematodes, the new isolate was able to persist right through the trial period, even in such extreme conditions. Further testing from 1998 until 2002 by Becker Underwood in a range of crops, temperatures and doses showed that the cold adapted nematode was able to control BVW at very low temperatures and also at warmer temperatures to the same level as current commercial products in the field (Fig. 2). Opening the window of opportunity
The HRI discovery presented a nematode that was able to achieve control of black vine weevil in cold field conditions, not just under protection. However, the nematode is also able to work at warmer temperatures and consequentially a new product is now available (Nemasys L). In summary, this nematode can control vine weevil infestations with applications extended to August through to June and March to June, exactly when the pest is active thus reducing pest outbreaks in the following growing season. How Do Nematodes Work?
Entomopathogenic nematodes are now a standard for the control of a wide range of pests including soil drenches for vine weevils, sciarids and slugs and foliar sprays for Western Flower Thrips and leafminer. The insect parasitic nematodes only kill insects. They enter through the mouth, anus or spiracles and can even bore their way through the cuticle and once inside, release symbiotic bacteria which kills the insect over the next 24 – 48 hours. All nematode products are found naturally in the soils of the country within which they are sold. Using these products significantly boost the numbers of nematodes in an area to control the targeted pests. They require no personal protective equipment and there is no harvest interval, allowing continuous use for the life of the crop. [top] Combat the evil Weevil
Two new species of vine weevil, which are among the most serious garden pests in southern Europe, are gaining footholds in
various parts of the UK according to national press reports (source: news release dated 7.10.02 – New Pests Attack London
Gardens – Max Barclay of The Natural History Museum discovers two vine weevils new to UK). Nemasys, the nematode biological
control for the native UK vine weevil, has been proven in trials to kill both of the newly introduced species of vine weevil.
Says Becker Underwood’s general manager, Dr. Graeme Gowling, for the nematode division, “We now have the full results of
our research and can confirm that the nematodes in Nemasys vine weevil killer have been proven to kill both the newly
introduced vine weevil species (Otiorhynchus armadillo and O. salicicola).
“The results are very impressive,” continues Graeme. “Similar to the results reported on our indigenous species of vine
weevil. Gardeners and growers can therefore expect excellent results from our product.”
The information for Graeme Gowling’s claim is based upon independent work at research institutes in Europe; for O.
salicicola, the work was carried out in Switzerland and for O. armadillo, the work was carried out by the Instudo Agrario
di S. Michele all’Adige, Italy.
The nematodes in Nemasys are natural enemies of the vine weevil larvae and are an effective, natural biological control
method for use both indoors and outside. Killing the larvae breaks the life cycle thereby reducing the future adult
population.
Vine weevil larvae attack the roots of the plant, so a drench of nematodes on the garden during August, September or
October will kill the larvae, without posing any risk to pets, wildlife or children. For indoor plants or greenhouses,
nematodes can be applied at any time for year round control.
Nemasys is a unique natural product – the beneficial nematodes it contains are natural enemies of vine weevil. These
microscopic worms are already present in the soil in small numbers. Nemasys adds more into the soil and once their work
is completed they die back to natural background numbers. As well as being highly effective the nematodes are not harmful
to children, pets and wildlife, leave no chemical residues in the soil and will never become pests themselves.
[top]
No Vine Weevils on our nursery
With vine weevils listed as number two pest on the RHS list of top ten garden pests (The Garden, March 2002), Kieran
Dunne of L&K Dunne Nurseries in Naas, County Kildare in Ireland can confidently say that by using Becker Underwood's
Nemasys he doesn't have a vine weevil problem with the two million plants that he has on his nursery.
Says Kieran, "We consistently use Nemasys twice a year on our nursery and have been doing so for seven years, during the
first week in September and then again during the first week of March. I would recommend this regime to any gardener who
needs to control vine weevil. Nemasys does work."
For a number of years Kieran used chemicals to control vine weevil, one of which was taken off the market due to
environmental concerns. Kieran was, therefore, pleased both from a health and safety point of view and from an
environmental standpoint, when Nemasys became available. He has had no problems with the control of vine weevil since.
L&K Dunne Nurseries are specialists in quality liner production and have been in operation for 20 years. They supply to
wholesale nurseries both in Ireland and the U.K. They are using natural pest control more and more, and especially so in
the control of the red spider mite and the sciarid fly. They employ 15 full time members of staff and are Members of
County Kildare Growers.
Nemasys is a unique natural product - the beneficial nematodes it contains are natural enemies of vine weevil - and
nothing else. These microscopic worms are already present in the soil in small numbers. Nemasys adds more into the soil
and once their work is completed they die back to natural background numbers. As well as being highly effective the
nematodes are not harmful to children, pets and wildlife, leave no chemical residues in the soil and will never become
pests themselves.
[top]
Vine Weevils in the Sussex Downs
When West Dean Gardens in West Sussex experienced a severe infestation of vine weevil in the mid to late 90s, gardens
supervisor, Sarah Wain, turned to Nemasys Vine Weevil Killer and has been using it ever since.
“Now if we see an adult vine weevil we don’t worry anymore because we regularly treat with Nemasys Vine Weevil Killer,”
explains Sarah who has been at the gardens for 15 years and is responsible for the day to day running of the walled garden
and horticultural highlights around West Dean Gardens.
There are two and a half acres of kitchen walled garden at West Dean plus 13 Victorian glasshouses and cold frames making
26 growing environments.
The plant quality in the greenhouses is wonderful and their policy is to grow as wide a selection of plants as possible
for public display. Sarah is very particular that the plants are top quality and presented at their best to their public
and with the display changing three or four times a year this means that a lot of the plants are container grown and in
ideal conditions to attract Vine Weevil.
To keep up this tight regime of total stock management, the pot plants are treated once a year in early summer with
Nemasys Vine Weevil Killer and the Vinery in early autumn.
[top]
Evil Weevil - an early check pays dividends
You may not think much is happening in the garden during January and February, but after a mild winter it’s always worth
keeping an eye out for pest damage. One of the most pernicious pests is the vine weevil, which attacks many garden plants
– some, such as fuchsias, cyclamen and begonias are particularly vulnerable.
Although most damage appears during the growing season, you may find that vine weevils are still active in the greenhouse.
You’re not only sheltering susceptible plants from the freezing temperatures, but vine weevils as well.
Adult weevils eat irregular-shaped notches in the leaf margins of plants – a characteristic sign that most gardeners can
identify. Such damage may only be cosmetic, but the larvae are more of a problem, devouring the roots until the plants
wilt and die.
Nematodes can be used to treat plants under glass all year round, and in the garden from early March, as long as the
temperature is above 5oC. All vine weevil adults are female and can lay around 1,500 eggs each, so an early treatment, is
worthwhile.
You can use Nemasys Vine Weevil Killer freely, because it is completely safe for plants and wildlife, indoors and out -
unlike chemicals which can’t be used on open ground or food crops. It is also environmentally-friendly, because the
nematode used is indigenous.
How does it work?
The product contains millions of microscopic worms (nematodes). Watered into the soil, these seek out the vine weevil larvae and kill them. The nematodes breed and new generations are released which continue to seek out more vine weevil larvae. Once all the larvae have been destroyed the nematodes die back to their natural levels. Nemasys Vine Weevil Killer will kill the larvae present and protect against further larvae damage for several weeks. If you have a minor infestation, one treatment may be sufficient. If the problem is more serious, treat again during the spring as well as the autumn. Nemasys Vine Weevil Killer is available in pack sizes that treat 160 pots or(12 sq.m/14 sq.yds) or 100 sq.m/125 sq.yds. [top] How a Victorian kitchen garden fights Vine Weevil
“Autumn is the time to apply Nemasys Vine Weevil Killer,” says HDRA head gardener, Mike Thurlow who is responsible for
the organic Victorian kitchen garden at Audley End, Saffron Walden, Essex. Mike has been at Audley End since 1999 and an
organic gardener for 20 years. He grows hundreds of pelorgoniums and a show of poor man’s orchids to give the greenhouses
colour for his hundreds of visitors. The greenhouses are also home to peach trees.
Says Mike, “We have used Nemasys Vine Weevil Killer for several years to keep vine weevil under control. I have personally
been using biological control since 1984 and have used it ever since because it works so well. I always say, as I tend
these Victorian gardens, that the one thing that we could give the Victorians is biological control. It is 100% foolproof.”
“I apply Nemasys in the autumn to eradicate vine weevil larvae and then I re-apply in the spring to make sure that grubs
don’t have a chance to turn into adults. I keep an eye on my plants to see if they have any of the tell tale notches.”
According to Mike’s records, well before biological control was available, Victorian gardeners used to kill the pest by
laying newspapers on the floor at night, then go out and shine a light on them and then quickly roll up the paper with the
adults on them and burn the paper with the vine weevil wrapped inside.
As vine weevil has become widespread throughout the UK, action to combat the pest in autumn is important to protect
plants from larvae that have hatched - before they cause damage to your valuable plants. Plants in open ground as well as
in containers are susceptible. Nemasys Vine Weevil Killer is the only solution for both open ground and containers. Simply
applied as a drench, the nematodes in Nemasys seek out and kill the larvae before they eat through the roots, which can be
fatal to the plants.
Adult vine weevils are all female and lay hundreds of eggs in the soil over the summer and autumn. The eggs hatch into
larvae, which are ‘C’ shaped and legless with a small head. They feed and grow throughout late summer and autumn starting
on the fine roots of plants and working their way up to the larger more important roots.
“An application of Nemasys Vine Weevil Killer between August and the end of November will target the larvae at the time
they are starting to cause damage to plants,” advises Dr Graeme Gowling, head of Becker Underwood’s nematode division, the
producers of Nemasys. “Killing them in the autumn makes sense as it stops them dead and so protects the plants for the
spring.”
Nemasys Vine Weevil Killer is available by mail order and through many garden centres. Full details can be found on the
nematode advice website www.nemasysinfo.com.
The nematodes used in Becker Underwood’s Nemasys range, which are safe for children pets and wildlife, are naturally
occurring organisms that are already present in the soil, but their numbers are not sufficient to deal with the annual
onslaught by pests. By using Nemasys the gardener adds more nematodes to the soil so that there are enough of them to
attack the target pest. Having dealt with the pests, the number of nematodes falls back to the background level of the
environment, their food source having been eliminated.
[top]
Killing Vine Weevil as nurserymen do
Nick and Sheila Chandler, who own and run The Old Withy Nursery in Gweek, Cornwall control vine weevil on their nursery
using Nemasys Vine Weevil Killer, showing why garden owners should do the same, both for containers and on open ground.
Says Sheila, “Plants in containers are especially vulnerable because they have a captive root system and in a nursery
situation we have pots galore.”
The Chandlers have used nematodes since they opened their nursery seven years ago. As spring application protects
established stock whilst an autumn application protects planted beds and stock plant areas.
“When nematodes are applied positive results on infected stock are apparent within a couple of days,” says Sheila. “Vine
weevil larvae may been seen in the compost and once the grubs are parasitized, they stop feeding and die. More importantly,
you have broken the life cycle so the grubs will not hatch info female adults, which lay more eggs.”
“We got the idea when I was a garden centre planteria manager,” says Sheila. “We were encouraged to use nematodes on older
stock, especially Rhododendrons that take years to reach a saleable size. The results were excellent and I was very
impressed. It’s easy to use, safe and when you weigh up the value of plants and time, it’s economical as well.”
“Vine weevil on our nursery has been almost eradicated by using Nemasys,” concludes Sheila, “and our other secret weapon,
my Pekin bantams, who eat the adults, are safe to roam because they are totally unaffected by the nematodes!”
Another nematode product that gardeners can use now is Nemaslug, which kills slugs. Applied now, it can protect valuable
plants for six weeks from one simple application. Nemaslug is also safe for children, pets and wildlife.
[top]
The therapy of using biological control
Root & Branch is a new horticultural therapy project for people with mental health difficulties. When Patsy Dyer,
Horticultural Director, first saw adult vine weevil ‘playing dead’ amongst the charity’s potted plants last year, she was
determined immediately to reduce any damage and any distress to gardeners. An order went straight in for parasitic
nematodes, Nemasys Vine Weevil Killer, Steinernema kraussei.
The gardeners began a regular ‘pest check’, looking out for any tell tale signs of notched leaf edges and adult pests
hiding in gravel and empty pots. A gardener noticed a couple of adults and the nematodes were watered in at the end of
August. Root and Branch now have no damaged plants.
Says Patsy, “The therapy aspect of gardening is appreciated the world over by those who are employed in the industry and
those who enjoy it as a hobby. But ‘garden therapy’ itself is sometimes a whole new world to people who are dealing with
mental health difficulties. Imagine then the elated feelings of your first successful plant propagation. Imagine
discovering some strange, ugly-looking white grub that has eaten and ruined the fruits of your labour. Not very
therapeutic for anyone.
“Knowing that Steinernema is a natural, host-specific killer of the vine weevil larvae, allows the gardeners to know they
are not causing harm to the environment whilst ensuring a successful crop. Also, by employing natural pest control, it
allows the developing garden to welcome a wide array of wildlife. All this adds to a relaxing, therapeutic project, where
after all the gardeners’ feelings are paramount.
Patsy is a former Senior Horticultural Advisor at Garden Organic (HDRA). Based in the Vale of the White Horse,
Oxfordshire, Root & Branch is an independent charity.
[top]
Applying Your Nematodes | Buy products | News | How nematode products are made | Quality & care | Links | About us | Contact us
News archives - Nemasys Vine Weevil Killer
- Press Information
- Louise's Rhododendrons were saved
- The lifecycle of a Vine Weevil
- Biocontrol of Vine Weevils in a cold climate
- Combat the evil Weevil
- No Vine Weevils on our nursery
- Vine Weevils in the Sussex Downs
- Evil Weevil - an early check pays dividends
- How a Victorian kitchen garden fights Vine Weevil
- Killing Vine Weevil as nurserymen do
- The therapy of using biological control
At the Royal Botanic Garden Edinburgh (RBGE), Supervisor Louise Galloway is in the process of planning her next overseas
plant collecting expedition to collect rare Vireya Rhododendrons from South-East Asia. She recalls a time five years ago;
when she watched helplessly whilst her beloved recently rooted cuttings succumbed to Vine Weevil.
Looking at the sick plants a colleague, who knew of Becker Underwood’s work, told her about Nemasys Vine Weevil Killer
and Louise has not looked back since. “I spent so much time propagating the cuttings,” said Louise, “that I was really
upset when I lost the lot to vine weevil. We no longer have a problem because we now use Nemasys Vine Weevil Killer twice
a year, in the spring and autumn.”
“I find the instructions on the packaging extremely easy to understand, the Becker Underwood pie chart is excellent as it
explains the lifecycle of the Vine Weevil and therefore tells you exactly when to target the pest, the website is very
user friendly too!”
Particularly loving the Vireyas, Louise knows how devastating it can be to lose them to pests. Vine Weevil have a
particular liking for Rhododendrons. The plants that Louise looks after are slow growing and have very fine surface roots
susceptible to damage therefore it is very important to protect them. Louise is responsible for the world’s largest
collection of Vireya Rhododendrons. Starting with only and handful of plants in the 1950’s, through expeditions and
collaboration with the scientific and horticultural staff in Edinburgh and overseas, the RBGE now hold approximately 165
out of the known 300 species of Vireyas, in total 2,672 plants to protect!
Louise started her career in horticulture when she was a Saturday girl in the RBGE’s visitors’ shop. Her love of the
plants that she was surrounded with encouraged her into full time horticulture; with on the job experience and day
release she gained SVQs in Amenity Horticulture, later achieving an HND in Horticulture with Plantmanship on the full
time course at the Garden. Louise has a particular interest in Integrated Pest Management and now she is a qualified
BASIS pesticide advisor she is able to advise staff throughout the garden on pest control with more and more of a
leaning to biological control.
At Edinburgh Botanical Gardens there are 10 public display glasshouses and over 20 behind the scenes research and
propagation houses, nearly two acres in total. Louise is responsible for the pest control under glass and she uses
nematodes wherever possible, using brand leader Nemaslug as an effective treatment against slugs especially in the Fern
House, and Nemasys for sciarid flies which can be a problem in the propagation areas.
“New 5 degree Nemasys Vine Weevil Killer is much more tolerant of the Scottish climate,” continues Louise, “and I will
keep using nematodes because I know they work. We grow many rare and endangered plants here in Edinburgh and I want to
make sure they stay as healthy as possible. With so many areas in the world lost to mans’ endeavours, we are the
custodians of a priceless plant collection and I feel very privileged to work here.”
[top]
The lifecycle of a Vine Weevil
Gardening is a popular pastime and massive numbers of container plants are produced yearly. However, many of the
insecticides used by commercial growers have been banned, such as aldrin which disappeared in 1989. Although this is
great news environmentally, vine weevil numbers have risen exponentially as a result and they've become a problem in many
gardens. And, as a native pest, they're always going to be around!
You can tell if you've got vine weevils because the adults eat characteristic circular notches in the edges of leaves,
usually choosing healthy evergreen plants. Although the damage looks awful, it's merely cosmetic - the serious damage is
happening underground where the larvae are active. These feed rapaciously on the roots, eventually causing the death of
the plant. If your plants are wilting as if they're dry, but the soil is moist, then give the leaves a gentle tug. If the
whole plant comes away in your hand, you may find that vine weevil larvae have eaten the roots. Many plants are affected,
especially those with fibrous root systems such as sedums, primulas and fuchsias. However, all containerised plants should
be checked regularly.
The most effective way of controlling the pest is by killing the larval stage - and to be successful at this, you need to
be aware of the life cycle. You can't kill the adults using insecticides and, being largely nocturnal, they're hard to see
unless you go out at night with a flashlight and pick them off by hand, then stamp on them hard - a satisfying sound! The
only stage you can kill easily is the larval stage.
One of the main problems is that all vine weevil adults are female and each produces hundreds of eggs parthenogenetically
ie without a mate. The eggs hatch to produce 'C' shaped, legless, larvae with a distinctive brown head - these feed
throughout late summer and autumn. During winter their feeding activity decreases as they move down into the ground, but
in spring they start feeding again. So the best time to treat the soil or compost is during the autumn, when the soil is
moist and above 5C. If the problem isn't severe, then treating the garden now should be adequate. However, you can also
treat during spring if the problem's severe.
Using a naturally-occurring nematode worm, Nemasys Vine Weevil Killer is the most effective way of controlling the pest
and is safe for children, pest and wildlife. The nematodes seek out the larvae and enter through natural body openings.
Once inside, they release bacteria that prevent the pest from feeding and it dies. The nematodes reproduce inside the
dead pest and release a new generation of hungry infective nematodes, which disperse and search for further prey.
Simply add the powder to a large bucket of water and mix thoroughly, then dilute it according to the instructions. Using
a watering can with a coarse rose or a hose-end feeder such as that produced by Miracle-Gro or Photrogen, water it on to
moist soil around the affected plants. Try to apply it during the evening to prevent it drying out and ensure the soil
remains wet so that the nematodes can move through the soil solution to find the larvae.
Bio® is a registered trademark of Bayer Crop Science. Slug Clear™ is a trademark of The Scotts Company and its
affiliates. Provado® is a registered trademark of Bayer AG. doff™ Slug Killer is a trade mark of Doff.
[top]
Biocontrol of Vine Weevils in a cold climate
Simon Piggott, Becker Underwood, Littlehampton, UK & David Chandler, HRI Wellesbourne, UK.
IntroductionThe Black vine weevil (BVW) is one of the major pest problems for growers of annual and perennial ornamentals and soft fruits. The characteristic notching around leaf edges is made by adult weevil feeding, but most economic damage is caused by larvae feeding on roots which in severe infestations cause the death of the plant. Many growers who have opted for the use of nematode biological control have found that soil temperatures can limit the use of currently available products. Such products are restricted to use in temperatures above 12oC and the application window is usually closed between mid-autumn to mid-spring. Nematodes
Entomopathogenic nematodes (EPN) are generally drenched onto compost or soil for the control of vine weevil during the autumn and again in the spring but with the restriction of a minimum of 12 oC. However, research during the early 90s by scientists at HRI led to the discovery of a new nematode isolate that was adapted to colder conditions. The HRI Project
Discovery
In 1990/91 a new nematode isolate (Steinernema kraussei) was found in Scotland that was able to infect and kill black vine weevil larvae at low temperatures. It was found that when tested at a temperature of 6oC (a temperature where commercial products are practically inactive) control was excellent but it was also found to be as good as commercial products at warmer temperatures. This is important as the isolate was shown to be suitable to replace existing nematode products. Further assessments were therefore carried out under more practical field situations. Field trials
When compared for 14 weeks from December to March with a commercial product against black vine weevil in field conditions, soils temperatures at a 10cm depth ran at an average of 2.7 oC (-1.5 to 7.3 oC). It was found that, as expected, the commercial product failed to significantly control BVW at such low temperatures. The new isolate killed up to 81% of the larvae (Fig.1) and, unlike the commercial nematodes, the new isolate was able to persist right through the trial period, even in such extreme conditions. Further testing from 1998 until 2002 by Becker Underwood in a range of crops, temperatures and doses showed that the cold adapted nematode was able to control BVW at very low temperatures and also at warmer temperatures to the same level as current commercial products in the field (Fig. 2). Opening the window of opportunity
The HRI discovery presented a nematode that was able to achieve control of black vine weevil in cold field conditions, not just under protection. However, the nematode is also able to work at warmer temperatures and consequentially a new product is now available (Nemasys L). In summary, this nematode can control vine weevil infestations with applications extended to August through to June and March to June, exactly when the pest is active thus reducing pest outbreaks in the following growing season. How Do Nematodes Work?
Entomopathogenic nematodes are now a standard for the control of a wide range of pests including soil drenches for vine weevils, sciarids and slugs and foliar sprays for Western Flower Thrips and leafminer. The insect parasitic nematodes only kill insects. They enter through the mouth, anus or spiracles and can even bore their way through the cuticle and once inside, release symbiotic bacteria which kills the insect over the next 24 – 48 hours. All nematode products are found naturally in the soils of the country within which they are sold. Using these products significantly boost the numbers of nematodes in an area to control the targeted pests. They require no personal protective equipment and there is no harvest interval, allowing continuous use for the life of the crop. [top] Combat the evil Weevil
Two new species of vine weevil, which are among the most serious garden pests in southern Europe, are gaining footholds in
various parts of the UK according to national press reports (source: news release dated 7.10.02 – New Pests Attack London
Gardens – Max Barclay of The Natural History Museum discovers two vine weevils new to UK). Nemasys, the nematode biological
control for the native UK vine weevil, has been proven in trials to kill both of the newly introduced species of vine weevil.
Says Becker Underwood’s general manager, Dr. Graeme Gowling, for the nematode division, “We now have the full results of
our research and can confirm that the nematodes in Nemasys vine weevil killer have been proven to kill both the newly
introduced vine weevil species (Otiorhynchus armadillo and O. salicicola).
“The results are very impressive,” continues Graeme. “Similar to the results reported on our indigenous species of vine
weevil. Gardeners and growers can therefore expect excellent results from our product.”
The information for Graeme Gowling’s claim is based upon independent work at research institutes in Europe; for O.
salicicola, the work was carried out in Switzerland and for O. armadillo, the work was carried out by the Instudo Agrario
di S. Michele all’Adige, Italy.
The nematodes in Nemasys are natural enemies of the vine weevil larvae and are an effective, natural biological control
method for use both indoors and outside. Killing the larvae breaks the life cycle thereby reducing the future adult
population.
Vine weevil larvae attack the roots of the plant, so a drench of nematodes on the garden during August, September or
October will kill the larvae, without posing any risk to pets, wildlife or children. For indoor plants or greenhouses,
nematodes can be applied at any time for year round control.
Nemasys is a unique natural product – the beneficial nematodes it contains are natural enemies of vine weevil. These
microscopic worms are already present in the soil in small numbers. Nemasys adds more into the soil and once their work
is completed they die back to natural background numbers. As well as being highly effective the nematodes are not harmful
to children, pets and wildlife, leave no chemical residues in the soil and will never become pests themselves.
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No Vine Weevils on our nursery
With vine weevils listed as number two pest on the RHS list of top ten garden pests (The Garden, March 2002), Kieran
Dunne of L&K Dunne Nurseries in Naas, County Kildare in Ireland can confidently say that by using Becker Underwood's
Nemasys he doesn't have a vine weevil problem with the two million plants that he has on his nursery.
Says Kieran, "We consistently use Nemasys twice a year on our nursery and have been doing so for seven years, during the
first week in September and then again during the first week of March. I would recommend this regime to any gardener who
needs to control vine weevil. Nemasys does work."
For a number of years Kieran used chemicals to control vine weevil, one of which was taken off the market due to
environmental concerns. Kieran was, therefore, pleased both from a health and safety point of view and from an
environmental standpoint, when Nemasys became available. He has had no problems with the control of vine weevil since.
L&K Dunne Nurseries are specialists in quality liner production and have been in operation for 20 years. They supply to
wholesale nurseries both in Ireland and the U.K. They are using natural pest control more and more, and especially so in
the control of the red spider mite and the sciarid fly. They employ 15 full time members of staff and are Members of
County Kildare Growers.
Nemasys is a unique natural product - the beneficial nematodes it contains are natural enemies of vine weevil - and
nothing else. These microscopic worms are already present in the soil in small numbers. Nemasys adds more into the soil
and once their work is completed they die back to natural background numbers. As well as being highly effective the
nematodes are not harmful to children, pets and wildlife, leave no chemical residues in the soil and will never become
pests themselves.
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Vine Weevils in the Sussex Downs
When West Dean Gardens in West Sussex experienced a severe infestation of vine weevil in the mid to late 90s, gardens
supervisor, Sarah Wain, turned to Nemasys Vine Weevil Killer and has been using it ever since.
“Now if we see an adult vine weevil we don’t worry anymore because we regularly treat with Nemasys Vine Weevil Killer,”
explains Sarah who has been at the gardens for 15 years and is responsible for the day to day running of the walled garden
and horticultural highlights around West Dean Gardens.
There are two and a half acres of kitchen walled garden at West Dean plus 13 Victorian glasshouses and cold frames making
26 growing environments.
The plant quality in the greenhouses is wonderful and their policy is to grow as wide a selection of plants as possible
for public display. Sarah is very particular that the plants are top quality and presented at their best to their public
and with the display changing three or four times a year this means that a lot of the plants are container grown and in
ideal conditions to attract Vine Weevil.
To keep up this tight regime of total stock management, the pot plants are treated once a year in early summer with
Nemasys Vine Weevil Killer and the Vinery in early autumn.
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Evil Weevil - an early check pays dividends
You may not think much is happening in the garden during January and February, but after a mild winter it’s always worth
keeping an eye out for pest damage. One of the most pernicious pests is the vine weevil, which attacks many garden plants
– some, such as fuchsias, cyclamen and begonias are particularly vulnerable.
Although most damage appears during the growing season, you may find that vine weevils are still active in the greenhouse.
You’re not only sheltering susceptible plants from the freezing temperatures, but vine weevils as well.
Adult weevils eat irregular-shaped notches in the leaf margins of plants – a characteristic sign that most gardeners can
identify. Such damage may only be cosmetic, but the larvae are more of a problem, devouring the roots until the plants
wilt and die.
Nematodes can be used to treat plants under glass all year round, and in the garden from early March, as long as the
temperature is above 5oC. All vine weevil adults are female and can lay around 1,500 eggs each, so an early treatment, is
worthwhile.
You can use Nemasys Vine Weevil Killer freely, because it is completely safe for plants and wildlife, indoors and out -
unlike chemicals which can’t be used on open ground or food crops. It is also environmentally-friendly, because the
nematode used is indigenous.
How does it work?The product contains millions of microscopic worms (nematodes). Watered into the soil, these seek out the vine weevil larvae and kill them. The nematodes breed and new generations are released which continue to seek out more vine weevil larvae. Once all the larvae have been destroyed the nematodes die back to their natural levels. Nemasys Vine Weevil Killer will kill the larvae present and protect against further larvae damage for several weeks. If you have a minor infestation, one treatment may be sufficient. If the problem is more serious, treat again during the spring as well as the autumn. Nemasys Vine Weevil Killer is available in pack sizes that treat 160 pots or(12 sq.m/14 sq.yds) or 100 sq.m/125 sq.yds. [top] How a Victorian kitchen garden fights Vine Weevil
“Autumn is the time to apply Nemasys Vine Weevil Killer,” says HDRA head gardener, Mike Thurlow who is responsible for
the organic Victorian kitchen garden at Audley End, Saffron Walden, Essex. Mike has been at Audley End since 1999 and an
organic gardener for 20 years. He grows hundreds of pelorgoniums and a show of poor man’s orchids to give the greenhouses
colour for his hundreds of visitors. The greenhouses are also home to peach trees.
Says Mike, “We have used Nemasys Vine Weevil Killer for several years to keep vine weevil under control. I have personally
been using biological control since 1984 and have used it ever since because it works so well. I always say, as I tend
these Victorian gardens, that the one thing that we could give the Victorians is biological control. It is 100% foolproof.”
“I apply Nemasys in the autumn to eradicate vine weevil larvae and then I re-apply in the spring to make sure that grubs
don’t have a chance to turn into adults. I keep an eye on my plants to see if they have any of the tell tale notches.”
According to Mike’s records, well before biological control was available, Victorian gardeners used to kill the pest by
laying newspapers on the floor at night, then go out and shine a light on them and then quickly roll up the paper with the
adults on them and burn the paper with the vine weevil wrapped inside.
As vine weevil has become widespread throughout the UK, action to combat the pest in autumn is important to protect
plants from larvae that have hatched - before they cause damage to your valuable plants. Plants in open ground as well as
in containers are susceptible. Nemasys Vine Weevil Killer is the only solution for both open ground and containers. Simply
applied as a drench, the nematodes in Nemasys seek out and kill the larvae before they eat through the roots, which can be
fatal to the plants.
Adult vine weevils are all female and lay hundreds of eggs in the soil over the summer and autumn. The eggs hatch into
larvae, which are ‘C’ shaped and legless with a small head. They feed and grow throughout late summer and autumn starting
on the fine roots of plants and working their way up to the larger more important roots.
“An application of Nemasys Vine Weevil Killer between August and the end of November will target the larvae at the time
they are starting to cause damage to plants,” advises Dr Graeme Gowling, head of Becker Underwood’s nematode division, the
producers of Nemasys. “Killing them in the autumn makes sense as it stops them dead and so protects the plants for the
spring.”
Nemasys Vine Weevil Killer is available by mail order and through many garden centres. Full details can be found on the
nematode advice website www.nemasysinfo.com.
The nematodes used in Becker Underwood’s Nemasys range, which are safe for children pets and wildlife, are naturally
occurring organisms that are already present in the soil, but their numbers are not sufficient to deal with the annual
onslaught by pests. By using Nemasys the gardener adds more nematodes to the soil so that there are enough of them to
attack the target pest. Having dealt with the pests, the number of nematodes falls back to the background level of the
environment, their food source having been eliminated.
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Killing Vine Weevil as nurserymen do
Nick and Sheila Chandler, who own and run The Old Withy Nursery in Gweek, Cornwall control vine weevil on their nursery
using Nemasys Vine Weevil Killer, showing why garden owners should do the same, both for containers and on open ground.
Says Sheila, “Plants in containers are especially vulnerable because they have a captive root system and in a nursery
situation we have pots galore.”
The Chandlers have used nematodes since they opened their nursery seven years ago. As spring application protects
established stock whilst an autumn application protects planted beds and stock plant areas.
“When nematodes are applied positive results on infected stock are apparent within a couple of days,” says Sheila. “Vine
weevil larvae may been seen in the compost and once the grubs are parasitized, they stop feeding and die. More importantly,
you have broken the life cycle so the grubs will not hatch info female adults, which lay more eggs.”
“We got the idea when I was a garden centre planteria manager,” says Sheila. “We were encouraged to use nematodes on older
stock, especially Rhododendrons that take years to reach a saleable size. The results were excellent and I was very
impressed. It’s easy to use, safe and when you weigh up the value of plants and time, it’s economical as well.”
“Vine weevil on our nursery has been almost eradicated by using Nemasys,” concludes Sheila, “and our other secret weapon,
my Pekin bantams, who eat the adults, are safe to roam because they are totally unaffected by the nematodes!”
Another nematode product that gardeners can use now is Nemaslug, which kills slugs. Applied now, it can protect valuable
plants for six weeks from one simple application. Nemaslug is also safe for children, pets and wildlife.
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The therapy of using biological control
Root & Branch is a new horticultural therapy project for people with mental health difficulties. When Patsy Dyer,
Horticultural Director, first saw adult vine weevil ‘playing dead’ amongst the charity’s potted plants last year, she was
determined immediately to reduce any damage and any distress to gardeners. An order went straight in for parasitic
nematodes, Nemasys Vine Weevil Killer, Steinernema kraussei.
The gardeners began a regular ‘pest check’, looking out for any tell tale signs of notched leaf edges and adult pests
hiding in gravel and empty pots. A gardener noticed a couple of adults and the nematodes were watered in at the end of
August. Root and Branch now have no damaged plants.
Says Patsy, “The therapy aspect of gardening is appreciated the world over by those who are employed in the industry and
those who enjoy it as a hobby. But ‘garden therapy’ itself is sometimes a whole new world to people who are dealing with
mental health difficulties. Imagine then the elated feelings of your first successful plant propagation. Imagine
discovering some strange, ugly-looking white grub that has eaten and ruined the fruits of your labour. Not very
therapeutic for anyone.
“Knowing that Steinernema is a natural, host-specific killer of the vine weevil larvae, allows the gardeners to know they
are not causing harm to the environment whilst ensuring a successful crop. Also, by employing natural pest control, it
allows the developing garden to welcome a wide array of wildlife. All this adds to a relaxing, therapeutic project, where
after all the gardeners’ feelings are paramount.
Patsy is a former Senior Horticultural Advisor at Garden Organic (HDRA). Based in the Vale of the White Horse,
Oxfordshire, Root & Branch is an independent charity.
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Press Information
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pr@dshpr.co.uk. Images are also available for use in publications on application to
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