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Category: Pests, Problems and Health

Pests, infections, disease, cultivation and growing problems

Stingers in the Garden Get Me Nettled

Stingers in the Garden Get Me Nettled

I was picking the Czar plums to make more jam when a wasp was disturbed from eating it’s lunch. Wasps go for my plums just as they are at their sweetest best. My problem was I couldn’t see which plums had a wasp in the fruit if they were above head height or facing away from my hand. The resulting sting set me on the trail of other stingers in the garden.

Plants Stingers

  •  Who has not been stung by a common nettle or the stinging nettle  a herbaceous perennial aka Urtica dioica. More likely to be stung walking on country paths or unkempt areas not in your garden I am sure!
  • The nettle family are stinging plants with  hairs on  leaves or stems that are capable of injecting formic acid that cause pain or irritation. Brushing bare skin against the leaves causes initial pain with the potential for more effects caused by histamine, acetylcholine and other chemicals that are also present.
  • Giant hogweed  contains a corrosive sap that causes severe rashes,  burns and even serious eye damage if you get the photosensitive chemicals  in your eyes . aka Heracleum mantegazzianum.
  • Poison ivy & its cousin, poison oakone is a noted rash-maker. It’s toxin, urushiol oil, is in the sap of the plant and present in minuscule quantities in some other food stuff.
  • Other plants, often those with hairs or irritating sap, can cause irritation and allergic reactions. I suffer with some verbascum Optunia cacti and euphorbia.

 

 

 

Enemies of Roses That Affect You

Enemies of Roses That Affect You

I do not want to start by worrying you but I am probably going too anyway! After an early summer of brilliant rose displays the down side is the number and volume of enemies our roses are having to contend with.

This is Nothing New

  • I am borrowing heavily from the National Rose Society publications including the title of this post ‘The Enemies of the Rose.’
  • The national rose society’s handbook on the insect, pests and fungus  of the rose was first published in 1908 – over a century ago.
  • My copy is the third edition from 1952. I can’t find a more recent edition nor current reprints. Old copies surface at secondhand booksellers and are crammed with over 150 pages of problems.
  • For example the contents include a virtual dozen references to a variety of different Sawfly but I get ahead of myself.
  • The evils of modern publishing have created a digitised Kindle 2012 edition (? scanned?) and it may be worth the 99p down load but it seems at variance to the older books.
  • The collective brains of an Entomologist, Zoologistand an expert in Cryptogams have been combined with 110 years of horticulture experience and specialist knowledge.

Picking Out Some Rose Enemies

  • I will not try to paraphrase or emulate the original record but will pick out bits worth further exploration.
  • Fungi and bacteria are classified as ‘Diseases’ and insects and sundry creatures as ‘Pests’.
  • Sadly developments over time plus health and safety worries have made many of the cures, potions, treatments, unctions, chemical controls and interventions illegal, outdated or unobtainable.
  • I am not sure whether Defra, European Union and sundry Ministries such as Agriculture  should be classed as ‘The Enemies of the Rose.’
  • Bad health in what ever form is potentially just a sign of a rose failing to achieve the growers ideals and aspirations.
  • Setting standards is essential but being able to cope with the consequences of weather, breeding, growing conditions and external influences can all be enemies of roses.
    • Pests include: thrips, aphids, leaf-hopper, caterpillar, rose maggots, chafer, leaf miner, sawfly, leaf cutter, gall wasps, ants, mites and other maggots and bugs.
    • Diseases include: black spot, rust, mildew, leaf scorch, anthracnose, cancker & die back, botrytis (grey mould), gall, silver leaf, chlorosis, sooty mould and variations on the virus and fungus themes.

Another digitised version  .  The Enemies of the Rose by George Massee Frederick Vincent 1868- Theobald National Rose Society (Creator) …

Read More Read More

Black Aphids on my Dahlias

Black Aphids on my Dahlias

These little breeders have been having a banquet on some of my Dahlias. They go for the soft new shoots and nascent flower stems which must be easy to get their teeth into. For some reason they have been quite selective on the plants they choose (As has been the spray I have used in a prophylactic manner). I hope the rest of the summer is black fly free but you never know.

Why are Black Fly Bad News

  • Black fly aphids or thrips are common sap-sucking insects. 
  • They are unsightly and look like they can do serious damage to plants.
  • As sap sucking insects they can create a lack of vigour and damage growth.
  • Insect secretions can go mouldy and add further problems to the dahlias
  • In severe cases viruses can be transferred to plants by these insects.

Lulled into a false sense of security by the low level of greenfly around my garden I wasn’t expecting black fly. I only left my dahlias alone for a few days and the flies multiplied like rabbits. I am on a more frequent look out patrol now. The muggy weather is one reason for the outbreak of black fly.

Winter Moth Problems on Fruit Trees

Winter Moth Problems on Fruit Trees

Fruit trees can be a winter home for a range of female moths. Amongst them are woolly aphis and capsid bugs plus other pests that emerge from the ground. They crawl up fruit tree stems and trunks in October to lay their eggs. The caterpillars hatch in spring and feed on the foliage and fruit.

Prevention and Treatment

  • To check the progress of these pests a barrier can be erected. Some fruit growers use a band of paper covered in tacky grease.
  • Tubes of special grease are now available specially for older fruit trees with rough bark where grease bands are less effective as pests can crawl under the band. Alternatively the bark can be smoothed first.
  • Winter moth and mottled umber moth need an  application at the beginning of winter before adult female moths climb trees to lay eggs. Apply again in summer to protect against ant infestations.
  • Rentokill call their product ‘Glue Bands’.
  • Grease any support stakes and low hanging branches.

Other Tips

  • Fix the grease band 1 ft below the lowest branch. Paint the stem with lime wash above the grease band.
  • Reapply after 2-3 months or renew the grease effect.
  • Also suitable for ornamental trees that are susceptible to infestation.
  • Keep bands free of dead leaves.

 

Why are Everyone’s Weeds Better than Mine

Why are Everyone’s Weeds Better than Mine

What is the collective noun for a group of dandelions?   A drift or adrift in my garden!

With so many potential ‘clocks’ ticking away to dispersal I wonder at the number of flowers on this fine weed. (Dandelion makes a wine but I am not so sure that it is quite so ‘fine’.)

Bindweed

Bindweed can be deceptively attractive except when flowering in my garden. I would call their group noun a ‘knot’ or a pestilence of convolvulous. Heaven forbid that they should become a congregation!

Soil and Healthy Grass

Soil and Healthy Grass

Grass Land, Meadows & Lawns

  • Getting to the grass root of the problem grass is the  largest irrigated crop in the USA.
  • Like other crops grass depends on the health of the soil in which it grows.
  • Moisture and nutrient retention is crucial to keeping your soil in good shape.
  • Clover is good news not bad news at least in moderation. I bit less attractive but a force for good with grass. Nodules on the clover store and deliver nitrogen more effectively than synthetic fertilisers.
  • Home chemical applications tend to be significantly over done compared to agriculture. Less not more is far better.
  • Water wisely in early morning. Evening watering can encourage some disease.
  • Allow clippings to fall back on the grass and rot down to keep the soil in good heart.
  • Higher cutting blades and grass helps prevent weeds and helps retain moisture.

Other Methods for Healthy Grass Lawns

  1. Scarifying – rake out the dead leaves and detritus
  2. Aerating  – spike the soil to allow air in and de-compact the ground
  3. Feeding – nitrogen rich food is the grass’s choice
  4. Top Dressing  – a bit of sand and soil brushed in helps new roots
  5. Moss Control – get rid of moss in spring
  6. Weed control – selective chemical weed killer
  7. Damage Repair – even the best lawns can get damaged – patches reseeding or just turning the edge of a turf around can help
Lily Beetle Spotting & Prevention

Lily Beetle Spotting & Prevention

What has got 6 legs, a head, 2 eyes and red wings and  is not a dice game of Beetle. It is the red lily beetle Lilioceris lilii that consumes large quantities of one of our favorite plants.

How to Spot Lily Beetle

  • Adults are 8mm long, bright red with a black head and legs.
  • Eggs are 1mm long and orange-red, found in groups on the underside of lily leaves and they hatch in around a week.
  • Larvae have orange bodies with black heads but are normally covered with their own slimy black excrement.
  • The fully grown larvae are 8-10mm long.
  • At the pupal stage they lie in the soil.
  • Both the adults and larvae can defoliate lilies and fritillaries in short order.
  • Leaves get ragged and black gungy deposits can be seen on infected plants.
  • The red beetles easily fall off leaves and hide in the soil when gardeners try to remove them by hand.
  • The beetle was initially confined to south east England but has spread north.

The Lily Beetle Cycle

  • Adult lily beetles emerge from the soil from late March to May and feed on  foliage between May and  September.
  • Adults feed and lay eggs on the underside of leaves of host plants from late April until early September.
  • After about two weeks, when the larvae are fully grown, they pupate in the soil. Two to three weeks later new adults emerge.
  • The beetles overwinter as adults in sheltered places, often in the soil but not necessarily near lilies.
  • This non-native pest became established just before the second world war.

Prevention, Predators and Parasites

  • Red lily beetle overwinters in soil, leaf litter and other sheltered places so good husbandry can help.
  • Small infestations can be picked off by hand. There is some pleasure in squashing a red beetle that has caused your plant so much damage.
  • There are some parasitic wasps but probably not enough to help your lilies survive.
  • The RHS to which I am indebted for this advice say ‘ Pesticides are likely to be more effective on larvae than adults
  • Heavy infestations which are impractical to remove by hand can be treated with pesticides
  • Organic insecticides containing natural pyrethrins  Several application of these short persistence products may be necessary to give good control
  • Synthetic pyrethroid pesticides such as lambda-cyhalothrin (e.g. Westland Resolva Bug Killer), or deltamethrin (e.g. Sprayday Greenfly Killer) can be used
  • The systemic neonicotinoid insecticide acetamiprid (e.g. Bug Clear Ultra) can also be used’
  • In my experience it is wise not to expect miracles with chemical treatments and beware they can kill pollinating insects.
Garden Problems Caused by Wind

Garden Problems Caused by Wind

Problems Caused by Wind

  • Wind desiccates leaves – moisture is gone with the wind
  • Even well rooted plants can be rocked by wind and this can be fatal to roses or fruit trees. Shrubs and tree growing at a slant caused by wind will never give of their best.
  • Wind abrades, rips and tears. I have just lost a good spray of chrysanthemums that I was looking forward to seeing in flower. Chrysanthemums stems often break near the joint with the main stem and I should have tied them up with more care or kept them out of the wind. Fleshy leaves like dahlias do not do well in wind.
  • A cold wind does no one any good and the wind chill factor can damage plants as well as gardeners.
  • In severe windy conditions pots can be blown over, loose debris scattered and even structural damage may occur. Pots appear top heavy when there is lots of growth that catches the wind. My clematis and runner beans  have caught the wind and both are leaning from the wind.
  • Trees and shrubs can be stunted by wind and will not reach thier normal potential. You seldom see giant trees on our windy coastline.
  • Unwanted seeds can be dispersed with only a gentle breeze

May all your winds be zephyrs and all your gales be miss spelt girls

Mildew on Oxford Roses

Mildew on Oxford Roses

The dry weather has cause a lot of problems with moldew. (I should have said mildew but that is a Freudian slip I will leave in.) The worst affected in my garden is an early flowering clematis but this rose stem is not far behind.

It was draping over a wall in the centre of Oxford with two immaculate flowers on an adjacent branch. Humid and still air plus lack of rain are to blame.

Avoid & Treat Mildew

  • Select roses that have been bred to be mildew resistant.
  • Roses get stressed particularly through lack of water. Mulch after a good rain and keep the mulch topped up
  • Spray badly affected plants with Rose Clear 3 to try stop spores spreading.
  • Limit nitrogen fertiliser which encourages sappy growth  that  is prone to attack.
Bolting and Running to Seed

Bolting and Running to Seed

Early Flowing Rheum Rhubarb

Bolting

Said of plants that are making seed prematurely. A plants purpose in life is to produce offspring usually by seed. When stressed they will trigger the reproduction button and set seed.

  • Lettuce and salad crops are prone to bolt and ‘run to seed’. The heart of the lettuce is then useless and the plant only fit for the compost heap.
  • Rhubarb and rheums also throw seed stalks taking energy from the good parts of the rhubarb. You can and should brake-off the offending stalk as soon as it is seen. Water the plant and hope the rest of the crop is unaffected.
  • Other vegetables such as members of the onion family are affected in dry and stressful conditions. This is due to the plants keenness to reproduce before it succumbs to a problem.
  • Broccoli and cauliflower whose flowers open early are not truly bolting but the cause and effect is the same.
  • Flowers that turn quickly to seed will inhibit more flower production. That is why sweetpeas and annuals, amongst others, should be deadheaded to prolong flower production.
  • Bolting may be an advantage when seed collection or production is the main aim.

‘……….there exist very little literature on the possibility of manipulating flowering for seed production’ but this book from amazon is an exception

Running to Seed

  • If vegetable plants  are allowed to set seed after flowering they may taste bitter.
  • Plants that rub to seed will probably stop growing new buds and flowering.
  • Regular cropping the stems of herbs like parsley, basil and mint delay their running to seed.
  • This old gardener is running to seed with no new growth on the top of his bald head.

Book Cover

 

 

Stratification is putting your seeds in a moist material outside over the winter to allow the variations in temperature to act on them, so that they will germinate when conditions are warmer. Seed used to be put in layers (strata) of damp sand,