Archive | Pests, Problems and Health

Pests, infections, disease, cultivation and growing problems

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 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

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

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

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

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

Early Flowing Rheum Rhubarb


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.

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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,


White Fly Infestations

My Experiences of Whitefly

Sometimes I am too tolerant and generally that is true with whitefly infestations. Perhaps that is because I have not had a serious outbreak or a great deal of resulting damage. So live and let live unless an edible crop is involved. The worst that happens is on houseplants where these sap feeding insects can breed continuously through the year. As a gift to the windowsill they leave a sticky secretion on leaves which drops from the plant. Only in the greenhouse have the white-winged adults taken to flight from tomato plants when disturbed. Adults and the scale like nymphs have secretions that can make plants sticky and prone to sooty mould.

Brassicas, particularly my broccoli  are prone to large collections of aphids and or white fly that make the crop unappetising. Who wants to eat bugs unless they are on a bush tucker trail. If picking and squishing is not enough control I remove affected leaves or use soapy water as a spray.

What the Experts Say

  1. There are many forms of whitefly including those on outdoor plants that are species specific for azalea, honeysuckle and  phillyrea. (Over 1500 species)
  2. Avoid getting Trialeurodes vaporariorum whitefly from newly acquired plants.
  3. Treatment and cures include the use of sticky traps, a parasitic wasp called Encarsia formosa a tiny, parasitic wasp that preys on the greenhouse whitefly.
  4. Some strains have become resistant to controls but a insecticidal soap may be an efficient control.Failing that try a systemic insecticide such as Provado ultimate bug killer.
  5. Ladybirds love eating whiteflies and they are very cheap. Encarsia Formosa is
  6. ‘Due to the whitefly feeding, plants can quickly become extremely weak and may be unable to carry out photosynthesis. Leaves will wilt, turn pale or yellow, and growth will be stunted.
  7. Check undersides of leaves around the veins for white insects, even if they aren’t visible, and feel leaf surfaces for honeydew. If the whiteflies are feeding, they’ll suddenly all fly off the leaves in a swarm, so it’s very obvious.
  8. A half-and-half mixture of petroleum jelly and dishwashing detergent, spread over small boards painted bright yellow, is sticky enough to catch little whiteflies. To whiteflies, the color yellow looks like a mass of new foliage. The bugs are attracted to the cards, get stuck in the jelly, and die.’  Old Farmers Almanac


Gardener! gardener!  there is a white fly in my soup – well button up!


Persicaria Knotweeds

When is a weed not a weed? Well not very often if it is growing in the wrong place. If you have planted Persicaria then that is Knot a weed it is a notweed or not depending on your spelling.

Persicaria affinis aka Polygonum affine Common Name: ‘Knotweed’ flower from late summer until the frosts with spires of red, pink or white flowers held aloft as with these massed plants by the lake at Grewlthorpe.

There are over 150 species of Knotweed which get their common name from the swollen nodes on the stems.


Soil Conditioners and Conditioning

Garden Chemicals

What is Garden Lime

  • I have just given a dose of lime to the areas in my veg plot that have been cleared for winter. I like to give a bit of extra magnesium to some soft fruit trees as well.
  • Often supplied as a powder of crushed limestone but also available as concentrated crystals.
  • Garden lime helps to maintain soil condition.
  • Calcium is consumed by vegetables and an extra supply is welcomed to replace calcium that has leached out of the soil by rain.
  • Lime reduces soil acidity.
  • Lime help break down heavy clay soils.

Garden Chemicals

During the summer I have occasionally fed my tomatoes with liquid seaweed fertiliser and we have had a great crop but I think most other growers had a good tomato season.

 What is Calcified Seaweed

    • Calcified seaweed is dried seaweed and lime or other calcium based salts
    • Calcified seaweed is an organic substance without any nasty chemicals. There is concern that it is no longer approved by the Soil Association for use in organic growing, due to concerns that the harvesting of this material is not sustainable and has adverse effects on the marine environment.
    • Seaweed is rich in minerals, encourages beneficial soil bacteria, helps improve heavy soil structure and neutralises acid soils.

Uses of Calcified Seaweed

    • As a soil improve and clay breaker it breaks up the heaviest clay without damaging soil pH.
    • As a compost accelerator it speeds up the breakdown of organic garden waste.
    • Seaweed adds trace elements and minerals to the soil.
    • Calcified seaweed neutralises acid soil
    • Adding seaweed is beneficial to bacteria and is used in lawn treatment.

Maxicrop Organic Cal-Sea-Feed Calcified Seaweed 6kg tub from Amazon


Blanching & Earthing Up

Blanching & Earthing Up Gardeners

  • Blanching seeks to make pale or white by excluding light.
  • Several vegetables need blanching to be made them tender and remove the green parts that cause bitterness.
  • Celery and leeks are blanched using the process of earthing up.
  • Seakale and rhubarb is blanched by excluding light by an upturned pot usually covered in leaf litter.
  • Endives can be blanched by covering with a slate or tile to exclude light for a few days.
  • Chicory and lettuce may blanch if the leaves are tied together.
  • Exclude light from potatoes by ‘earthing up’ or drawing mounds of soil  around the haulms (stems) to prevent tubers from growing near the surface and turning green.

Blanching Food Treatment

  • Blanch vegetable or fruit by scalding in boiling water and finally plunge into icy or very cold water.
  • Skin and outer shells are easier to remove on tomatoes and many nuts after quick blanching.
  • Fruit and vegetables are treated  to minimize the bacterial content often as a precursor to freezing.
  • Blanching helps to retain a green color with asparagus, greens, peas and beans. Par boiling is similar to blanching but without the last step of a quick chill in cold water.
  • Blanching food is now a recognised industrial process about which several learned views have been published.

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