“Pests and Diseases” was the subject of a talk given to Littleton and Harestock Gardening Club by its President, Ray Broughton, lecturer and horticultural consultant.
Ray has used a powerful microscope to examine and observe a range of the aphids that feed on the sap of plants, as shown in slides. The knowledge gained is necessary for accurate control. We were reminded that milk, vinegar and salt are not now approved and that any pesticides must have approval and that all must be used with regard to safety.
In the vegetable garden plant Tagetes, to deter insects, especially whitefly, noting that it is the dead flower heads that are effective. Plant Alyssum, (now called Lobularia) ,since fungus will go on that, rather than on the vegetables. This is known as a sacrifice plant in companion planting. To avoid disease we must clean our garden equipment thoroughly. A hedge trimmer was found, on examination, to have eight diseases. Leave secateurs in tomato ketchup for 3 or four days to remove burr, which is the plant resin.
The Spanish slug is now spreading in the Home Counties and on contact can cause dermatitis. The Oak Processionary Moth is poisonous. The Asian Hornet, large and fearsome-looking in the slide shown, is here, so care is needed not to bring back its eggs from abroad inadvertently. Ladybirds do not, as commonly believed eat aphids; they bite the head and suck out the liquid. The Harlequin Lady bird does the same and can kill 200 aphids a day, so it is useful. Two Spot Ladybirds tend not fly, they walk, so buy them, as they stay. The Blister Aphid spreads a virus on raspberries and other woody plants, so hose them down in December, which repels the overwintering adults. Red spider mites acquire their red colour on mating, in August. Red spiders in the spring and early summer are not red spider mites and are beneficial.
Use Nematodes now: they do not actively kill the vine weevil: the bacterium in the Nematode is transferred to it, and does its work. The Pea Moth is programmed to fly on to the leaf and then the flower and deposit its eggs, so use leafless pea plants. To deter caterpillars put moss killer the day before on the area to be planted. Rose Gall is disfiguring, but harmless. The Leaf Cutting Bee has many mandibles, hence the “cut outs” on the leaves. There is no chemical control for Fuchsia Mite: remove the flower tops where it settles and use Invigorator. Box Blight starts in May: use Invigorator while it is still white.
For clean, wireworm-free potatoes, plant the seed potatoes one inch down and cover with organic barley straw then spray them with a mix of tomato fertilizer and water. They can be left there as late as October. Brassicas: when spraying use lukewarm water which renders the leaf structure more accessible, and thus will kill aphids. Carrot blight; use malt vinegar and water 50/50 between the rows and not on the plants.
Whitefly and scales: Whitefly is a moth and if using chemicals they must be suitable for whitefly. To avoid scabby potatoes, cut newspaper into squares (Mirror or Sun because these papers are not waxed); dip in water and place on the seed potatoes, then the fungus can’t get in. Star Crack Virus is a common disease when potatoes are collected for up to three years as seed potatoes. Big bud mite spreads the virus like disease known as reversion. Re potato blight: an app is available free from The British Potato Association giving blight alerts for different areas. Cover potato plants with fleece for three days. Leeks: to avoid pest damage, place a 25cm pipe over each plant at planting time.
Ensure you use good quality seed when sowing a lawn as it pays dividends in results. Treat Red Thread with nitrogen, and “Fairy Rings” with moss killer in lukewarm water. Spray molehills with moss killer every two months. To kill slug eggs, use vinegar.
As always, Ray gave us some useful general information and guidance. If plants have too little carbon dioxide they become “leggy”. To avoid this, fill a Tupperware container with lumpy manure; place cling film on top and tie down. Pierce the film with 6 holes and place in the greenhouse; effective and no smell!
To set an accurate temperature check all day in the greenhouse; cover a coffee jar in silver foil and a polystyrene top and put a thermometer through it. This is called a temperature integrating jar. Use static electricity to collect seed cast too densely in a tray by moving a pen around the spot. Use conversion pots for good drainage. Growers are now using lamps which provide a balance of red and blue wavelengths; the blue light makes the plant stocky; the red makes the plant taller.
Runner beans – choose white flowering varieties such as “White Princess” which are wind pollinating – rather than the red. Smart seed is more effective as the seeds germinate very quickly and are resistant to birds.
Thistle in the grass: gouge out the centre and the plant will die. To make your own organic fertilizer, collect stinging nettles before they flower. Break them up. Put fleece in the bottom of a pot. Buy aquatic stones. Put the nettles in the pot, add Vermiculite and cover with fleece and the stones. Use once a week. This is totally organic and has 30 nutrients.
In your planting use SB Plant Invigorator to kill soft bodied insects and fungal diseases, and a final reminder – Clean the water butt!!
A talk rich in interesting, practical information, delivered with Ray’s characteristic style and gentle humour.