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Category: Pests, Problems and Health

Pests, infections, disease, cultivation and growing problems

White Fly Infestations

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

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

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

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.

Book Cover


No Chemical Pest Control

No Chemical Pest Control

No Chemical Pest Control

The world is made up of chemicals and they are not all bad. Where would we be without oxygen for example. However chemical control to kill ‘pests’ is often harmful to the environment and other wildlife. Many persecuted pests are not actually harmful to gardens or can be effectively controlled using other measures:-

  • Encourage natural predators of  specific pests.  Ladybirds and lacewings love to eat aphids. Frogs and hedgehogs go for slugs and if you want birds they have to eat something.
  • Biological controls introduce one killer insect to predate another; Whitefly can be targeted by a parasitic wasps.
  • Hand picking problems like the red lily beetle may be time consuming and intensive but is therapeutic for the Lily and the gardener. Removing and squashing caterpillars from brassicas is an old remedy .
  • Water spraying with  a light soap solution has been used for some time to remove aphids. Add plant oils and other organic based substances like garlic to the water for an environment friendly solution solution!
  • For my Tomatoes I companion plan French marigolds to distract predatory insects from the tomatoes.
  • Barriers from rabbit & deer fences to slug traps are chemical free. Slugs do not like copper  or the sharp edges of eggshells.
  • Think on about appropriate garden practice and methods like raised beds, crop rotation and good soil conditioning.

Leave Well Alone

  • You do not need to remove the pest completely but are aiming to protect your plants and crops from serious damage. Many creatures we think of as pests are seen by some desirable creatures as food.
  • Encouraging more diversity within the garden will prove beneficial.
  • Ants are unsettling but benign and do not do much damage to flowers and crops.If possible leave the ants to carry on.
  • Consider the whole food chain and be cautious before using any chemical. Remember the song Ilkley Moor Baht’at, after we’ve buried thee, worms will eat thee up, then ducks will eat up worms, we will eat up ducks and then we shall all have etten thee!
  • Piles of rotting wood, nettle beds and nature zones are better than obsessive cleaning up.
Rose Blindness

Rose Blindness

A disappointing display of flowers on rose bushes and climbers can be a result of ‘rose blindness’.  The term blindness in gardening terms refers to the failure to flower and is common in daffodils that become constricted (see below).

black-spot on rose tree

Reasons for Poor Flowering

  • Due to environmental conditions in some years roses flower badly despite the best efforts of gardeners.
  • An empty flower case can be caused by frost damage.
  • Poor fertility in the soil and lack of trace elements and nutrients
  • Excessive shade
  • A build up of old wood and weak growths
  • Infection such as this severe case of blackspot
  • Some varieties are just prone to intermittent blindness

Avoiding & Curing Rose Blindness

  • Careful positioning of your roses in the sun without too much competition from other plants.
  • Improve cultivation to relieve stress, add humus, water regularly, apply fertilisers and fungicide if needed.
  • Reduction in the amount of old wood to encorage new healthy shoots.
  • Cut back a blind shoot by half it’s length to stimulate further growth

Cure for blind bulbs

Daffodil Blindness

A better rose with a super scent that a blind person would appreciate.

Storage Rot of Tubers and Bulbs

Storage Rot of Tubers and Bulbs

Bulbs that are stored over winter can be susceptible to rot and fungus. To avoid problems check them regularly and remove and destroy any that are effected.

Ornamental bulbs, tubers and corms that may be affected include begonias, gladioli, tulips and dahlias. Edible crops that can be affected include potatoes, onions and garlic. You will know about rot when you smell some of these .

Onion Rots Ontario Ministry of Agriculture, Food & Rural Affairs

Types of Bulb Rot

  • Damp conditions help grey  botrytis or blue/green penicillium fungal rots.
  • Damaged items allow bacteria to enter the bulb and grow.
  • Post-harvest rots are also caused by fungi and bacteria from the soil or from infections in rotting leaves prior to harvesting.
  • Species specific fungal attacks can cause gladioli core rot, tulip fire, onion neck rot and others.

Storage Tips

  • Harvest carefully, damaged goods rot quickest.
  • Clean off soil and  dry off excess moisture. I then wrap some bulbs in newspaper.
  • Look for signs of black seed-like sclerotia of botrytis.
  • Discard any with signs of soft soggy tissue.
  • Store in dry cool conditions on clean storage trays. Leave space so bulbs do not touch and spread any disease.
  • Dust with a sulphur based inhibitor.

Sack rot and cart it off but not to your compost heap!

Good Bugs Bad Bugs

Good Bugs Bad Bugs

Bug eyed but not spritely.
Book Cover

During May we featured several common garden pests and bugs. Now before we leave the subject a few more comments.

You can get more by experience or via a book, magazine and further online info sites. eg cut-flower insects and mites

Experience of Bugs
Book Cover

  • If you garden for any length of time or even like to have a bunch of flowers in the house you will be bugged at some stage.
  • Stressed plants can be susceptible to aphids. you should see my lupins after a water shortage.
  • Insects at all stages of their life feed on something and they are likely to affect some of your plants. You should see my stripped French Marigolds at the moment. They were only planted in the greenhouse to keep the white fly off the tomato plants!
  • Slugs and snails and puppy dog tails or at least 2 out of the three will chomp through unprotected plants. My rhubarb has even succumbed this year to holey leaf, still we can’t eat that bit of the plants.
  • Sgt Pepper is the only beatle number I want in my garden not Colorado Beetle or Cucumber Beetle. So far so good but that is tempting fate.
  • My first early potatoes will be picked next week and I hope to have escaped cutworm, wireworm,  tuberworms  flea beetles and sundry maggots. Again tempting fate.

Good Bug

  • Some may think the only good bug is a squashed bug I beg to differ.
  • All gods creature have a place in the choir- some sing loud some sing higher …………
  • Ladybirds other than harlequin ladybirds (Harmonia axyridis) are known for eating aphids so I know which I want in the garden.
A Weed Worth $Billions – Seaweed

A Weed Worth $Billions – Seaweed

Comfrey juice concentrate or nettle juice stink but Seaweed extract is a weed to feed your garden. In fact seaweed is arguably the best weed in your garden.

Seaweed is an algae generally living in saltwater. There are over 10,000 species in green, brown and red.

Uses and Benefits of Seaweed

  • Seaweeds are important ecologically and are an important source of oxygen. 70% of the worlds oxygen comes from photosynthesis of algae and plankton.
  • Seaweed is an important food in Indonesia and the far east where Nori and Kelp are cultivated to make one of the largest  aquaculture industries.
  • Most seaweed grows in low-lying rocky environments on the shoreline. All those anchored to rocks or the seabed are safe to eat.
  • Seaweed is a source of chemicals with medicinal and industrial uses including processed foods such as  yoghurt, health drinks and agar for German beer .
  • Seaweed as a soil conditioner has been used in Ireland for many years bulking up earth on thin limestone soils. It is organic and can be added to compost heaps but let rain wash out excess salt first. In Europe seaweed is used, mixed in layers with sand and soil, for growing Potatoes and Artichokes. Unless you live very close to the sea you are unlikely to have access to large quantities so you may use a commercial liquid concentrate.
  • Concentrated Seaweed is used at high dilution rates. It is reputed to help plants avoid stress and resist frost. The natural hormones amino acids and beneficial carbohydrates in Seaweed help plant growth and strong root systems. The seaweed extract helps the take up of trace elements.
  • Seaweed can be used  to remove undesired nutrients from water such as ammonia, ammonium nitrate, nitrite, phosphate,metals and CO2.  Nutrients are  consumed by the seaweed which can then be harvested.

Tips for Use by Gardeners

  • Use a very dilute solution of SM3 seaweed extract as a foliar feed.
  • Seaweed retains water and is slow to decompose so use as a winter mulch.
  • Use it on vegetables and see if your crop yield is better
  • Soluble Seaweed Extract Powder is non-toxic, harmless and a designated fertilizer for organic farming.

Types of Seaweed

  • Red and brown algae are almost exclusively marine seaweeds. Green algae are also common in freshwater.
  • Green algae including river species and red algae are recognised as being in the Kingdom Plantae.
  • Brown algae with 1800 species includes Kelps  range from the Arctic to New Zealand.
  • Wracks or Fucus species are common in the UK with other brown seaweeds Saccharina latissima and Bladerlocks.
  • Sea Grapes (green caviar) and Sea Lettuce Ulva are popular green seaweeds
  • Eucheuma, Dulce, Carola and Ognonori are edible red seaweeds
  • Sargassum is floating plankton like seaweed.

Brown algae Ascophyllum nodosum cc 2.5

Caterpillar Brassicas Problems and Cures

Caterpillar Brassicas Problems and Cures

Small Cabbage White Caterpillar (pic)

Large Cabbage White Caterpillar are yellow with black markings

Caterpillar Problems

  • There are a large variety of caterpillar from different species of moths, butterflies and saw flies.
  • Brassicas are particularly susceptible to three common types the large cabbage white butterfly, the small cabbage white butterfly and the cabbage moth respectively Pieris brassicae, Peiris rapae and Mamestra brassicae.
  • Butterflies lay their eggs on the outer leaves of the brassica which hatch in 4 days to become voracious feeding larvae.
  • In addition to eating irregular shaped holes in leaves they often burrow into the hearts of cabbages.
  • Damage to plants will occur in April and October as the butterfly produces two generations per year.

Caterpillar Control

  • Avoid the butterflies by netting the brassicas.
  • Pick off any caterpillars by hand.
  • Squash any eggs that are found under the leaves before they develop.
  • Try a biological control from a parasitic wasp that lays its eggs in the caterpillars eg Cotesia glomerata
  • Grazers natural formula is sprayed directly on to the foilage which helps protect the plant from damage.
  • Spray with the contact pyrethroid insecticides but remember you plan to eat the brassica.
  • Distract the butterflies by planting nasturtiums as an alternative breeding ground.