The Good the Bad and the Ugly

Shield Bugs

…..this was seen on the Parish Walk on 27th September so we said that we would find out about it!

The name shield bug is due to the shield shape of the adult insects when seen from above.  It is  native to Britain and is of widespread occurrence, especially in southern England A fully grown  common green shield bug (Palomena prasina)   can be  up to  10mm long. It is bright green and stippled with tiny black dots in spring and summer, but changes to greeny-bronze in autumn.

They are often seen basking in the sun in late summer on a wide variety of plants.

The native common green shield bug is harmless although sometimes mistaken for beetles, shield bugs belong to a different group of insects, the Hemiptera. They feed by sucking sap from a wide range of plants but generally cause no noticeable damage to cultivated plants, even when numerous. Adult shield bugs hibernate in grass tussocks or leaf litter and emerge in May.

It is sometimes called a green stink bug as it produces a pungent odour from special glands if handled or disturbed.

It eats plant sap and leaves of trees, shrubs and herbaceous plants.

In 2003, another species of shield bug, the southern green shield bug (Nezara viridula) was found for the first time breeding in the London area. This recent arrival from elsewhere in Europe is slightly larger than the native green shield bug. The adults are uniformly green and lack the dark area at the rear end of the body. This species can cause damage to some vegetables, especially runner and French beans, but whether it will become established to the extent that it becomes a pest remains to be seen! At the moment it appears that it does not become numerous until late summer or early autumn, by which time beans are coming to the end of their cropping period.

Codling Moth

This time of year when you eat an apple or pear you may find a maggot, or worse half a maggot in it. This is the caterpillar of the codling moth. I used to think that by placing either a grease band or grease on the trunk of the trees it would stop this but although this might help it is not the best remedy. An organic method is a  pheromone trap which is hung in the tree to catch male moths in April and May and will cut down the infestation. Another  organic method is a  pathogenic nematode (Steinernema carpocapsae) which is available by mail order from some suppliers of biological  controls.

Chemically you kill young caterpillars before they enter the fruit by spraying apple and pear trees with bifenthrin in the second or third week of June. Follow this up with a second application about three weeks later.

Grease and grease bands  will protect against Winter Moth. These caterpillars are the pest that eat holes in leaves, blossom and young apple fruitlets. Severe attacks can weaken plants. Extensive damage to fruit trees can affect crop yields and quality.

The adult codling moths lay their eggs on or near developing fruit. These eggs hatch into small white caterpillars, which eat their way into the fruit and feed inside whilst it is developing. The caterpillars may be found inside the fruit at harvest time, but have usually eatent their way out to overwinter on the bark of the tree. They will then pupate and hatch into adult moths the following Spring, ready to mate.

 

Remove infected fruit as soon as any damage is evident to limit overwintering caterpillars.

The caterpillar’s exit hole is often visible in the side of the ripe fruit or at the ‘eye’ end (opposite to the stalk). When the fruit is cut open, the tunnel and feeding damage inside the core can be seen, together with the caterpillar’s excrement pellets.

Moles

Common throughout Britain though rarely seen, moles (Talpa europaea) spend most of their lives in a series of tunnels, only the familiar molehills above ground giving them away. Arriving from almost thin air you wake up one morning to mole hills. It only takes a couple of days to turn your perfect lawn into a scene from the “battle of the Somme”. The damage that moles do is incidental as they burrow in search of insect larvae, slugs and Earthworms and lawns are an ideal hunting ground. The worms are near to the surface and the network of grass roots supports extensive tunneling. Establishing a centre the mole or moles will work out digging several feeder tunnels and once the basic network has been formed they sit back and wait. With an excellent sense of smell and hearing they can detect a worm up to 5 metres away. As the worms work through the soil they drop into the moles tunnel and become another tasty meal.

Moles are highly territorial creatures – solitary outside of the breeding season – and a single individual’s network of tunnels sometimes covers as much as four acres. This inevitably means that, rather like the human housing market, competition for prime locations is strong; several young are born each spring, leaving home within a couple of months of birth to establish their own territories. Ridding yourself of one resident mole is no guarantee that another will not appear to take its place.

Deterrents

Various approaches have been tried over the years to repel moles, with varying degrees of success. Traditional methods include putting prickly vegetation – holly leaves or bramble cuttings, for example – or moth balls, creosote or any one of a number of other strong smelling substances within the tunnels. Another method involves part-burying a number of bottles, so that when the wind blows over their tops, the noise below ground upsets the moles and they will move away to somewhere more peaceful. A variation on this theme uses the familiar toy windmill. Sticking a few of these, it is said, into the ground – or in the necks of buried bottles – might send Mr Mole packing. Trapping is often the best method for young inexperienced moles. The normal type of trap has a scissors action which to be honest is somewhat barbaric. Another method often used involves finding the run then using a special mole smoke to fumigate it but although on the whole this is an effective method, you are however limited to how far the poisonous smoke will travel and also the moles can dig there way out of trouble. The smokes contain sulphur and can only be used when the weather is warm as in cold damp weather the smoke will not travel in the runs.

Sometimes it may be worth considering whether the molehills can simply be tolerated.

Ground Beetle

Not all insects are pests. There are some that are beneficial by eating other small garden creatures, some of which may be pests.

A typical ground beetle is the large ‘black-clock’ beetles, 10-20 mm long, often seen scampering across the ground or hiding under stones and logs in the garden,. Nearly all are extremely beneficial and help control garden pests . . . . . .

The Carabidae, or ground beetles, are one of the largest and best known families of beetles (Coleoptera), with over 20,000 different species worldwide – about 340 of these occur in Britain. Most species are nocturnal and sombrely coloured black or brown, but a few display iridescent and metallic blue, bronze, green or reddish reflections, and the family also includes the brightly coloured, and mainly diurnal, tiger beetles.

A typical black ground beetle (Pterostichus melanarius) found commonly in gardens   and farmland where it preys on aphids, caterpillars, wireworms, slugs and other pests
Carabid beetles and their larvae are mostly carnivorous, although some probably also scavenge on the dead remains of insects and other invertebrates, whilst others feed extensively on vegetable matter, especially plant seeds. A few of the carnivores are specialized caterpillar or snail hunters, or prey on a fairly narrow range of small insects such as aphids, springtails and mites; but most species are not very fastidious and a mixed diet of many different invertebrates, and  ground beetles are extremely beneficial and important predators which help in the natural control of many garden and crop pests, such as grasshoppers, crickets, termites, aphids, plant bugs, leaf beetles, weevils, wireworms, chafer grubs, butterfly and moth caterpillars, sawfly caterpillars, crane flies (leatherjackets), fruit flies, gall midges, many other fly pests, as well as slugs and snails. Ground beetles lay eggs in the soil or in accumulations of organic matter.

The larvae are elongate, relatively soft-bodied grubs that have three pairs of legs near the head end.

The head, thorax and usually some of the abdominal segments are brown or black but the underside is creamy white.

The larvae remain in the soil or leaf litter, where they feed on small invertebrate animal and their eggs.

Please do not kill these when you find them in your garden, garage shed etc. They may look bad but are your friends and are a free form of pest control (or The Good Guys)

Slugs and Snails

Slugs and snails are the most common pests in British Gardens. Most slugs and snails feed at night, and the tell-tale slime trails, if present, will alert you to the level of activity. Damage is most severe during warm humid periods It’s pretty impossible to eradicate slugs and snails from your garden. Even if you were to lace the beds with toxic pellets and do nightly picking patrols, new creatures would quickly glide in from neighbouring properties .Slugs and snails do play a necessary role in the ecology of a garden. They break down decaying matter; disperse seeds and produce rich compost like waste. They are food for birds, frogs, toads, hedgehogs, ground beetles and ducks. Slugs and snails are hermaphrodites (they have both male and female reproductive organs). But they rarely fertilize themselves, and usually mates with another animal after an elaborate courtship.

They produce slime to assist mobility. Slugs remain active throughout the year, unlike snails, which are dormant during autumn and winter.

Slugs are soft-bodied molluscs which are the familiar slimy pests that cause havoc in the garden, eating and making holes in leaves, stems, flower buds, flowers, roots, corms, bulbs and tubers of many plants. There are about seven species of slugs that are garden pests. They can cause damage throughout the year on a wide range of plants, but seedlings and new growth on herbaceous plants in spring are most at risk! Each slug can eat twice its body weight daily and lay 500 eggs a year. That means a single slug can potentially have 250,000 grandchildren!. Most slugs live in or on the soil surface, but keeled slugs (Milax species) live and feed mostly in the root zone. Warmer weather, combined with damp conditions greatly increases their activity. Slugs are most active after dark or in wet weather. Reproduction occurs mainly in autumn and spring, when clusters of spherical, yellowish-white eggs can be found under logs, stones and pots .

There are 29 species of Snails in Britain, the fastest of which is the Speckled Garden Snail that can travel at 50 metres per hour. They are common and widespread in Britain and Europe. Although snails need moisture they can survive for long lengths of time in unfriendly hot and dry environments by going inside their shell and pulling down a thin white membrane like a shade. They can survive without moisture for at least 4 (four) years. Isn’t that depressing?

You may see the following symptoms:

They are herbivores and feed on decaying vegetation, algae, fungi, lichens and plant leaves. As a part of their herbivorous diet they often feed on garden plants and are therefore considered a big pest. Most snails have thousands of microscopic tooth-like structures located on a ribbon-like tongue called a radula which works like a file, ripping the food into small pieces.

 

  • Slugs and snails sometimes leave behind slime trails, which can be seen as a silvery deposit on leaves and stems.
  • They cause irregular holes in plant tissue made by their rasping mouth parts. They can kill young seedling by completely eating them.
  • Black keeled slugs (Milax spp.) live underground and tunnel into potato tubers and bulbs.

Control

Slugs and Snails are so abundant in gardens that some damage has to be tolerated. They cannot be eradicated so target control measures on protecting more vulnerable plants, such as hostas and young vegetable plants.

Biological control

A biological control (‘Nemaslug’) specific to slugs, with no adverse effect on other types of animal, is available in the form of a microscopic nematode or eelworm that is watered into the soil. The nematodes (Phasmarhabditis hermaphrodita) enter slugs’ bodies and infect them with bacteria that cause a fatal disease.A moist soil and soil temperatures of 5-20ºC (41–68ºF) are required, therefore control is most effective during spring to early autumn.

Chemical control for Slugs and Snails.

Scatter metaldehyde slug pellets  ( examples are Scotts Slug Clear Advanced Pellets, Bio Slug and Snail Killer Pellets, )  thinly around vulnerable plants, such as seedlings and young shoots on herbaceous plants. A liquid formulation of metaldehyde (Scotts Slug Clear) is available for watering on to ornamental plants and the soil.Pellets may harm other wildlife, pets and young children if eaten in quantity, although slug powders based on aluminium sulphate (such as Doff Slug Attack) are less toxic .A relatively new form of pelleted bait containing ferric phosphate (Growing Success Advanced Slug Killer and ‘Sluggo’  ) It causes the snails to stop feeding and die in several days   is also relatively non-toxic to vertebrate animals. In addition what is left from the Sluggo is good for the soil Most plants, once established, will generally tolerate slug damage and control measures can be discontinued. Other non chemical controls

Preventive measures you can take include:

  • Transplant sturdy plantlets grown on in pots, rather than young vulnerable seedlings. Protect transplants with plastic bottle cloches.
  • Place traps, such as scooped out half orange, grapefruit or melon skins, laid cut side down, or jam jars part-filled with beer and sunk into the soil near vulnerable plants. Check and empty these regularly, preferably every morning. Proprietary traps are available from garden centres.
  • Place barriers, such as copper tapes (Fito Slug Stoppa Tape, Agralan Copper Slug Tape, Growing Success Slug Barrier Tape) around pots or stand containers on matting impregnated with copper salts (Slug and Snail Shocka, Agralan Slug and Weed Mat). Moisture-absorbent minerals can be placed around plants to create slug barriers (New Horizon Natural Slug Barrier, Fito Slug Stoppa, Growing Success Slug Stop, Vitax Slug Off, Gem Slug n Snail Repellent). Gel repellents (Westland Slug Blocker Eco Barrier Gel, Greenfingers Slug Defence Gel) can also be used to create barriers around plants. All of these products are available from garden centres.
  • Go out with a torch on mild evenings, especially when the weather is damp, and hand-pick slugs into a container. Take them to a field, hedgerow or patch of waste ground well away from gardens, or destroy them in hot water or a strong salt solution.
  • Some birds, frogs, toads, hedgehogs, slow-worms and ground beetles eat slugs and these predators should be encouraged in gardens.
  • Rake over the soil and remove fallen leaves during winter so birds can eat slug eggs that have been exposed.

Bees

They need your help to survive. In return they will pollinate for us.

We have all heard of the decline of honey bees (Apis Melliferi). Bees, via pollination, are said to be responsible for 15 to 30 percent of the food consumers eat so it is something that we should all be concerned about as it could well either result in food shortages or at least more expensive food. It is estimated that the commercial value of bees in the UK is £200M/year

We have seen hardly any Bees in our garden this spring in spite of having lots of blossom waiting to be pollinated.

The honeybee decline, often called ‘colony collapse disorder’ which is affecting domesticated and wild bee populations around the world, is mostly the result of diseases spread as a result of mites and other parasites as well as the spraying of crops with pesticides, scientists say.

Among the greatest problems is the varroa mite, a bloodsucking parasite that attacks young and adult honeybees. Attacked bees often have deformed wings and abdomens and a shortened life span.

“The varroa mite is also really effective at transmitting disease, particularly viruses,” Frazier said. Left untreated, a varroa mite infestation can wipe out a bee colony within a few months.

Toward the top of the list is the search for so-called biological control agents. One such agent scientists are looking at is a fungus that attacks mites but not the bees. However, research has yet to find a way to effectively deliver this fungus to a bee colony.

There is research looking at the possible use of a fungus which attacks the mites but not the bees. Mmm we will wait and see

Researchers are meeting some mite-control success by simply increasing the ventilation of managed bee colonies. Most colonies are airtight by design, to protect honeybees from the elements and it could be likened to the effect of travelling on an airplane.

“If anyone on an airplane has a cold, you are exposed to it. If they are sneezing, you have the potential to catch that cold,” he said. “Bee colonies, too, are airtight. Once the pathogen is in there, it will have a better chance of spreading.”

The spotlight has also been placed on the decline in plant diversity. This is mainly in agriculture but also in our gardens as we all follow fashions in planting or use more decking and concrete. In parts of America bees are used commercially to pollinate crops and are taken from farm to farm but often there will only be one plant such as almonds. Over there bees are dying in huge numbers. In one study in Italy bees were dying in the valley where there was only Almond blossom (with not even weeds) , whereas further up the valley the farmers had small fields and farmed the old way with lots of types of plant as well as wild flowers. In that area the bees were thriving.

Recent research has shown that bees fed on five types of pollen had a stronger immune system than those fed on one type of pollen and that this may be due to the formation of essential chemicals and fat with the variety. This could be one reason why bees often do better in urban areas rather than rural as there is a greater variety of plants due to the larger number of gardens. Some people even keep them on their roof (if it is not too steep!)

Schemes are trying to follow this up and for example the Coop is funding a project to increase beekeeping in urban areas (specifically Manchester, Inverness and London). They are offering training courses of several days, free equipment and contact details of existing beekeepers.  The Coop says that people are more ready to become involved in saving bees and one of their spokesmen said “If you talk to people about the lack of diversity in the oceans, say, they respond: ‘What do you want me to do about it?’ But when you talk about bees, people can do it in their own homes and their own lives.”

In the UK, where farmers are already rewarded financially through country stewardship schemes for implementing wildlife-friendly measures, it is thought that there is some scope for turning the trend and giving some diversity back to the foraging bees with for example in the past hedgerows being a resource that’s much neglected. Schemes like this make landscapes much more attractive as well, so it’s a win-win situation.

The French government has just announced a project to sow nectar-bearing flowers by roadsides in an attempt to stem honeybee decline.

Maybe we can help in some small way by making sure that we have as great a variety of pollen and nectar producing plants in our garden as possible. Maybe you can even have an excuse for leaving a few weeds. Just tell the neighbours that it is for the bees.

The Coop Plan Bee campaign has also sponsored an investigation into the population status of Britain’s native version of the honeybee, the black bee, which was replaced in many hives by the Victorians and more recently with an Italian bee strain, on the grounds that the native insect was too aggressive and did not produce enough honey. But it is possible that the black bee may be able to survive conditions in the 21st century better. Maybe the same old story.

Due to Colony Collapse Disorder and the decline in their honeybee population there is obviously a decline in pollinators in your own garden and this affects those of us who grow fruit and veg. The solitary bee, the Orchard Mason Bee (Osmia lignaria), is one ideal solution to the problem of pollination. Orchard Mason Bees are extremely gentle and will not sting unless threatened by rough handling. They are also more efficient pollinators than their cousins, the honeybee. An Orchard Mason Bee’s pollination success rate is 93%-99% as opposed to the 3% pollination success rate of honeybees. As a result, it takes fewer Orchard Mason Bees to fully pollinate an area than it takes honeybees to pollinate the same area.

Attracting and maintaining an Orchard Mason Bee population is quite simple. Make sure you have plenty of flowers in your garden, build a nest, provide a mud collection site. To provide a nest the easiest way is to drill ¼ to 5/16 inch holes in a piece of wood. Make sure the holes are clean of debris as they do not like a messy home. Fix the wood to a pole or tree and if possible protect from rain with another piece of wood. Easy and cheap!!!!!

You can, as we said earlier chose those plants which help bees and these are examples :

When deciding on varieties choose plants with different shaped flowers as different species have different lengths of tongues and anyway it is lovely to have different flowers around your garden.

In addition Ivy and Shrub Willows are great sources of pollen late in the year when there is not enough around. Another good excuse/reason to not pull all of that ivy of the tree or hedge.

But any nectar producing flowers are useful and these are best in south facing border if possible, and remember the earlier advice to have a variety.

What other practical things can we do to help bees, wasps (some species do a lot of good), and hoverflies.

Make sure that there is at least one patch of bare earth in a warm sheltered place. South facing banks are particularly attractive to some species of pollinators.

Retain some dead wood, maybe at the back of a bed as a feature as this will provide opportunities for other insects especially some solitary wasps which are useful.

Species that you may encounter in your garden other than hopefully honey bees:

Hoverflies such as Marmalade hoverfly or Drone fly

Bumble bees (did you know that there are lots of species of these?)

Solitary Wasps

Solitary or Mason bees

Bee Facts

  • Honey bees usually fly up to 1.5miles in one excursion for pollen and nectar, but some may fly up to 7.5miles, visiting upto 100 flowers and reaching speeds of 15m.p.h.
  • To make a pound of honey, a bee would need to visit 3.3million flowers and travel 90,000miles (3 times round the world). So do not waste honey.
  • The average worker honey bee obviously only makes a tiny proportion of this. Each one makes about half a teaspoon of honey in a whole lifetime, which is another reason why it matters so much that colonies are declining. Next time you eat a teaspoonful of honey just stop to think that you have eaten the whole lifetimes output of 2 bees.

Cabbage White Butterflies

Well summer is here and if you grow any greens in your garden you cannot relax as the scourge of the Cabbage White is here. I must try to remember that it is often called the summer snowflake (a lovely name) the next time I am vainly trying to chase them off my vegetable plot.

The female is distinguished from the male by the presence of 2 black spots, together with a black dash, on the forewing upperside.

In fact there are 2 different species – namely the large white butterfly, Pieris brassicae, and the Small White butterfly Pieris rapae so even though they look similar you will probably be fighting a foreign invader as well. The small white is a native species in the UK whilst the large white usually migrates from southern Europe. Large white butterflies have been seen crossing the English channel in huge swarms.

The reason for the migration is that only the Small White can pupate and survive the British winter.

After mating  each female lays a few hundred eggs, on the leaves of cabbages and related plants. You may think that you are better having the Small White because the Large White’s eggs are often laid in batches of ten to 20, whereas the Small White’s eggs are laid singly. The eggs can be laid at a rate of 4 per minute so if you turn you back for a very short time they will beat you!. Each egg is laid directly on the foodplant (rather than on top of other eggs) and also abuts other eggs, resulting in an organised egg mass. An individual female may lay up to 600 eggs in total and these hatch in a week or two, depending on temperature. Even after hatching you may still think the Small White is better because the Large White eggs hatch into yellow and black slightly hairy caterpillars in about two weeks and after feeding for a month or more and can reach 50mm in length before they turn into pupae. On the other hand the small white’s eggs hatch into bright velvety-green caterpillars which remain smaller. Beware though, as unlike the large white, these caterpillars often burrow into the hearts of cabbages to feed so you could have an unpleasant surprise with your lunch.

Cabbage white caterpillars leave their food plants when ready to pupate and usually attach themselves to a vertical surface such as a fence or wall with a silk girdle before their final skin shed. It is therefore worth a look around later in the season to try and cut down on the over wintering pupae, but to be honest it will probably be butterflies from someone else’s garden which cause you problems.

The numbers of cabbage white vary considerably from year to year due to weather, immigration and diseases.

Control

Treatment

Prevention is best if you can do it.

Covering plants with insect-proof mesh or fleece can help a lot but if there is a gap and one or two butterflies get in the damage might happen without you noticing. Also using fleece can lead to overheating during the warmer summer days. On the other hand if you can stop the butterflies getting in it is the best way. Do not forget that any leaves pressed against a net are fair game for the butterflies

Do not remove any parasitised caterpillars but move them to plants where new caterpillar infestations are expected as the parasites may kill new infestations. You can recognise these as the old large dead (sometimes dry looking) caterpillars.

Encouraging insectivorous birds within the garden by using bird-feeders in winter and nest boxes in spring is claimed to help but in our garden they do not seem at all interested in this bumper food source. It may be because the larvae accumulate poisonous oils in their bodies which deter birds etc.

You can buy a naturally occurring bacterium, Bacillus thuringiensisto spray on which kills only caterpillars and not the predatory insects, and is claimed to be very effective.

We are often advised to plant colourful, high nectar plants to help bees and other pollinators but do not plant them near the cabbage patch as these will encourage adult butterflies into the garden.

Chemicals

Pyrethrum

Bifenthrin

These are both effective against the butterflies but ask for advice at the garden centre and read the label carefully.