Tuesday, 14 May 2019

U3A Gardening Group Presentation on "Pests and diseases"

Gardening Group One 
deals with Pests and Diseases

Stephen hosted this meeting and twelve members of the group attended. We were also treated to home-made herb scones and biscuits, delicious.

The meeting started by saying that Jon Allbutt had been contacted on behalf of the group to thank him again for his help and advice on pruning given at the last meeting. A very informative email was received from Jon which was read out. 

Stephen then introduced us to this month’s topic - garden pests and diseases. Teacher and website wiz that he is, he had put his research onto his TV screen, as well as giving us all a handout with colour pictures! Not fair Stephen you make it a hard act to follow.

Garden Pests and Diseases
As gardeners, we all face challenges. Pest, insects, animals, birds and also humans!
Apparently the BBC garden website lists 115 relatively common pest and diseases. The ones that we all know are ants, blackfly, blackspot, blossom end rot, cats, frost, leather jackets, mealy bugs, slugs and snails, potato blight and tomato blight and that just covers 14% of the problems.

They are listed in alphabetical order on the website HERE

If you know the name of a plant, it also lists 12 pages of plants with common diseases and pests associated with them. You'll find them HERE.

RHS does an annual survey of the top ten plant pest and diseases. The article can be found HERE

Organic controls
Stephen gave information on these as it is hard not to use easy methods of control but we know that these can be harmful to wildlife.
  • Slugs and snails can be attracted by leaving out decaying organic matter and then inspecting and collecting up the offenders after dark and killing them by dropping them into a bucket of salt water.
  • Copper rings can be placed around the base of susceptible plants.
  • Shallow dishes filled with beer sunk in the ground, the molluscs become intoxicated and drown. Nice way to go!
  • Gravel, sharp sand, ashes, soot, crushed eggshells around plants also deter.
  • Nematodes but these are only effective against slugs.
  • Growing plants with rough or hairy leaves.
  • Products containing ferrous phosphates are supposedly safe for wildlife and do not contaminate the soil.

For Blackfly:-Inspect plants and remove as many aphids by hand, remove badly infected shoots and stems. Spray infected areas with a strong jet of water (be careful not to damage your plants). Encourage ladybirds, hoverfly and lacewing into the garden.
For greenhouse plants, purchase parasitic wasps of aphids (Aphidius matricariae and Ervi)

Things that also help to protect are making sure plants you are bringing into your garden are from a reliable source and are healthy. A good idea is to keep new large perennial plants isolated for a while to ensure they are healthy.
Also, place plants in the right place. Keep garden tools and equipment clean. Clean pots and trays between uses. Monitor plants regularly.

Stephen found that some of the most helpful and straight forward advice was from
Thompson and Morgan:-
  • Avoid too much high nitrogen fertiliser as this promotes soft leafy growth which attracts garden pests.
  • Erect physical barriers, covering crops with fleece or frit cages.
  • Know your enemy, then it’s easier to identify and tackle.
  • Good garden hygiene. Tools and areas clean.
  • Cultivate correctly. Watering, feeding, good soil conditions.
  • Encourage natural predators. eg ladybirds.
  • Chemical Controls:-follow instructions properly.

You'll find all of this advice HERE

There are other challenges linked to weather conditions, clay soil, animal and human damage. But looking at the various websites listed may give some help in dealing with these.

Thank you Stephen for all the information you collated. 

We were given notes about all of these areas and you can find them HERE
This is a comprehensive review of the topic with advice, questions and links to websites that may help.