All my tomatoes grown in a raise bed got blight in less than 48 hours. Should I destroy the plants and what can I do about the soil in the raised beds? Can I sterilise and grow other vegetables and most important of all please what can I do to avoid getting blights in the future? Tomato blights is a very common disease when the weather is damp especially from June onwards so there’s a warning sign here this year after the weather we had over most of June this year. It is caused by the same pathogen that’s responsible for potato blight. Outdoor tomatoes are more prone it than greenhouse tomatoes. Normally blight is seen in the south west spreading rapidly from airborne spores originating in gardens, allotments and particularly adjacent to commercial potato crops Currently there are no chemicals that amateur gardeners can use to treat blight so cultural methods have to be used. Infested plant material should be removed as fast as possible, Ideally burn it but it can go into a green waste collection bin. You don’t need to sterilise the soil –just turn it over to a depth of more than 18 inches and you’ll be fine. More gardeners who are fed up with the threat and often reality of blight are turning to blight resistant varieties which are not guaranteed to take the problem away but are certainly worth trying.
Bryan Potter, Cullompton
MY PLUM TREE ISN’T GOING TO PRODUCE ANY FRUIT THIS YEAR. THERE WAS VERY LITTLE BLOSSOM AND NONE OF THE FRUIT SEEMS TO HAVE SET. WHAT IS LIKELY TO BE THE PROBLEM? Nigella Oakley, Taunton
Plum tree problems range from age-related issues to disease and even pest issues. Extreme cold during flowering will cause the blooms to drop too early the cold weather during April seems to have hit some fruit crops Low temperatures before blooms open will also kill the flowers. Without flowers, you will have no fruit. Insects that chew the terminal ends, shoots and flowers will also cause no fruit on plum trees. One of the most common causes of plum tree problems is the lack of a co-pollinator. Plums are not self-fruitful and need another of the same species nearby for pollen transfer. This is done with bees, moths and other pollinator’s help. Pruning at the wrong time and too late in the spring removes the buds necessary for flower and then fruit. There are steps you can take to prevent the problem. Keep weeds and grass away from the base of a tree. Provide good irrigation and especially on young trees fertilisers high in phosphorus will help with blooming and fruiting. Bone meal is a great source of phosphorus at the base of trees. Also remember heavy bearing trees may not produce fruit the next year. The plant’s reserves are depleted and you will just have to wait a year for it to rally. Fixing plum trees with no fruit sometimes just requires patience and good stewardship.
My greenhouse cucumbers are growing to about three inches long and then shrivelling and dying quite dramatically. The leaves turn a mottled light green and white. I can’t see any obvious problem with them.
P hilip Davison, Petersfield
It may be the problem is red spider mites, a garden pest that affects a wide variety of plants, which most commonly affect azaleas and camellias but can also have a deadly affect on cucumbers. A plant that is infested by too many red spider mites will start to look unhealthy and will have a dusty appearance to the undersides of their leaves. Close inspection will reveal that the dust is actually moving and is in fact the spider mites. The plant may also have some webbing on the underside or on the branches of plant. You cannot easily make out the details of red spider mites with the naked eye but a simple magnifying glass can make the details more visible. A red spider mite will be all red. You can also use organic sprays to safely eliminate red spider mite but the best way to eliminate them is to make sure you don’t get them in the first place. Work to keep plants healthy and the areas around the plants free of debris and dust to keep red spider mites away. Also, make sure plants have enough water. The water will help keep the red spider mites away as they prefer very dry environments.
The leaves at the base of my grape vine are turning yellow. Is there anything I can do and is this the start of a more serious problem? The leaves at the base of your vine will be the oldest and will be the first to change colour and shed in the autumn. However this is all a bit too early for this to be happening and it should raise some alarm bells. For the time being and it might be an idea to give the vine some extra care to make sure there is nothing slowing down the development of the grapes. Apply a control release general fertiliser and mulch with a deep layer of well rotten manure to give the whole plant a bit of a pep up.
Annie Dillon, Cheltenham
The August 2019 issue of Cornwall Country Gardener Magazine