realenglishfruit

Top fruit tree growing advice and information from Real English Fruit

Category Archives: Pest and disease control

Tasks for garden fruit trees in June – part 2

Check your pheromone traps for codling and plum moths. Renew the lure if necessary. Start spraying the apple varieties which have a tendency towards bitterpit in the fruits. Apply fruit nets where bird trouble might occur, cherries in particular. Continue thinning out the fruitlets to doubles or singles. Remove scabby fruits at the same time. Start the summer pruning programmes of plums, cherries and greengages. The same applies to nectarines, peaches and apricots. Hang rolled up corrugated cardboard in the trees to attract the caterpillars which would otherwise damage foliage and fruits. Regularly inspect and renew when caterpillars are caught. Deal with aphids if present in too large a number in folded-up shoot tips. Do not let the trees dry out. This in particular applies to potted trees. Continue with foliar feeding if foliage of the fruit trees is not up to the mark. Make a start on preparing the ground where new trees will be planted in the autumn.

After natural drop, in June it is advisable to reduce the number of fruitlets in a group like this

After natural drop, in June it is advisable to reduce the number of fruitlets in a group like this

Peach leaf curl disease

Peach leaf curl disease (Taphrina deformans) is the main issue you have to be aware of with peach, nectarine and apricot growing. I f you follow my guidelines you will have no trouble with this fungal disease.

Apricot has the same trouble, but in a milder form. However, if you cover your peach tree or your apricot tree with a double layer of garden fleece from late January until the middle of May, every year, or bring the potted tree indoors during the winter months, the disease cannot develop.

Peach leaf curl

Peach leaf curl, photo courtesy of Scot Nelson/flickr.com

The fungus Taphrina deformans attacks the tree species of peach, nectarine and apricot.

The symptoms are the development of large reddish blisters on the leaves. The tree is seriously weakened as photosynthesis by the leaves is seriously affected.

Eventually the tree is starved to death as it is no longer able to make essential carbohydrates through photosynthesis. Leaves tend to fall prematurely and growth comes to a full standstill.

The fungus attacks the tree from early February until the middle of May. After May the fungus is no longer producing spores and therefore cannot cause new infections.

How to avoid peach leaf curl disease

There are various options for controllilng this fungus. Some varieties are more resistant than others. However this is no help if you already have to cope with this problem.

Actions to be taken immediately are the complete removal of leaves affected. This applies to the fallen leaves as well as the affected leaves that still attached to the tree. Make sure the leaves are all collected up, put in a plastic bag and then put in the non-recycling bin. Make sure the tree is well watered and does not stand in a carpet of weeds and grass. Apply a full watering can of water once or twice a week, particularly during the summer months. Mulch the tree with well rotted farmyard manure. The area to be mulched must be of a minimum size of one square yard.

Never let the tree go short of water! By late January cover the tree with a double layer of garden fleece. Fasten the fleece securely. Make sure the wind cannot affect it or lift it off. Keep your eye on the tree and if a tear develops in the fleece after particularly bad weather, repair the damage properly. This fleece needs to stay in position until the second week of May. After that time, carefully remove the fleece.

Never prune the tree during the autumn and winter months when the leaves have fallen. It is at that time that new infections occur very quickly. Prune during the middle of May or during late August, making sure the old wood is removed to make room for new shoots to form. This is essential as the fruits of peach and nectarine are formed on one year wood only. Seal the pruning cuts with “Prune and Seal”, a compound available from your garden centre. The foliage of a well pruned tree dries up quickly, with less chance of new infections.

If it is not possible to cover the peach tree, to avoid the disease you can spray with copper during the first week of February and repeat the spray 14 days later. Follow the instructions on the packet in detail. Garden centres stock it. At leaf fall in late November put on another spray of copper.

Peach leaf curl disease is spread by rain droplets. The fungus over-winters and is hidden in crevices of the bark and between the bud scales. Therefore consider planting a peach tree in a 15 to 18 inch diameter pot. By the end of January, wheel the potted peach tree into a cold shed or a cold green house or a cold poly tunnel. In that way no fleece is needed as the tree is sheltered from the winter rains. By the middle of May it is safe to take the pot outdoors again. Then position the tree in a warm sunny place and water it weekly or twice a week when very warm weather is occurring. Never let the tree go short of water as it will surely die.

Feed the tree monthly with a suitable foliar feed , obtainable from garden centres.

May orchard update – grubs in plums or apples

If last year you found grubs in your plums or apples, now is the time to do something about it. Depending on the severity of the problem, the correct pheromone trap will reduce or eliminate the damage.

If you have plum trees, please make sure a pheromone trap is placed in the tree. This will reduce or eliminate damage by the plum moth. The same principle applies to apple trees, but in this case the trap to be hung in the tree is the codling moth pheromone trap.

Continue to water young fruit trees. Make sure the one square metre of clean soil around the trunk of the fruit trees stays without grass and/or weeds. This is to ensure that your watering is to the benefit of the young fruit trees, and not the weeds and grass.

Pheromone trap, photo courtesy of MPaola Andreoni/flickr.com

Pheromone trap, photo courtesy of MPaola Andreoni/flickr.com

Death of established fruit trees

Apart from old age, some times trees die unexpectedly, even at a young age.
The death of fruit trees can be caused by several factors:

1) Collar rot
2) Armillaria root rot
3) Soil contamination with aggressive chemical substance
4) Tree canker
5) Tree trunk restriction
6) Drought.

Drought is often the cause if the trees are not cared for and the competition of grass and weeds is too severe, combined with a long dry period. If this is not the case, then a careful examination of the tree will need to be carried out.

Examine the tree trunk very carefully. Is there an obstruction that has grown into the tree trunk and is causing severe restriction? If this is the case some new and healthy-looking young shoots will appear below the restriction. This will also be the case if tree canker is girdling the tree. Next, use a sharp knife to peel back a portion of the bark on the trunk. If no healthy yellowish cambium under the bark is present and the wood is brown and dead, then points 1, 2 or 3 , as mentioned above, are the most likely causes of the tree trouble. An example of Point 3 is when a chemical substance such as concentrated weedkiller has been poured onto the ground next to the tree.

If this is not the case, we will then be left with points 1 and 2 as the most likely cause. In both cases, the chance of the trouble spreading to other trees becomes an issue, because the fungus remains active on the tree roots. If it is the armillaria fungus, the toadstools will appear around the trunk in the late autumn period. However the bootlace-like fungal threads will then already have arrived around the roots of your nearest fruit tree or ornamental tree. In that case grubbing the tree in total is the only option.

Summarising, if after a detailed examination, you find that the likely cause of tree death is armillaria, then you will have to grub the tree immediately, remove it off the site, roots and all, and burn it, as soon as you can. Armillaria fungus is very active in finding and infecting its next victim.

Whatever the outcome of your examination, my advice is to always use new, clean soil if you want to replant a fruit tree this coming autumn. Taking in consideration crop rotation principles, do not plant apple after apple or pear after pear etc. Vary the tree types. So, for example, apple after pear will be fine.

Armillaria

The illustration above is from “The Book of gardening: a handbook of horticulture”, 1900, edited by William D. Drury. It is accompanied by the following text:
“Armillaria mellea (Agaricus aielleus) This is a most destructive fungus found upon living ornamental trees, such as Conifers, as well as upon orchard trees. It is responsible for the disease known as Tree Root Rot. The fungus is most abundant, and is found both as a saprophyte and as a parasite. The clusters of Mushrooms at the base of trees are very familiar; they are, moreover, conspicuous alike as to size and colouring. The cap is of a pale yellow, with darkish scales upon it; the stem is also yellow. The fungus finds access to healthy trees either by means of its spores, which germinate on an injured part of the bark; or by means of the very peculiar mycelium, which is black and stringlike, and always endeavouring to penetrate the roots of healthy trees. The only thing that can be said in favour of this fungus is that its sporophores, or Mushrooms, are edible, though not particularly rich in flavour, being somewhat strong. Care should be taken to carefully remove and either eat or burn all specimens of the fungus, so that the danger of trees being infested by the spores which are shed is minimised. The mycelium found under the bark is white and felted. Once a tree has been badly attacked nothing can save it from destruction, as the mycelium spreads under the bark with considerable rapidity. Preventive rather than remedial measures should be adopted. These may well consist in the removal of all dead stumps on which the fungus is growing as a saprophyte; and in isolating the infected live trees.”

Weekly update for the fruit garden – fourth week of August 2015

Wasps have been a real hindrance all round, due to the changes in weather patterns. As a result, fruit which has been damaged by wasps or birds is now showing the usual signs of brown rot developing. It is very important to remove this fruit and dispose of it. Irrespective of whether the fruit still is hanging on in the trees or has already fallen on the ground, if it is left there, the spores of the fungus may be developing on the remaining fruits. Orchard hygiene at this stage needs to be taken seriously.

If the trees have been growing strongly, this is the right time to carry out summer pruning. Details of the summer pruning technique are explained in the Pruning Section on the website www.realenglishfruit.co.uk

This is also the right time to prune away surplus growth on trees which are being trained as cordons, fan or espaliers or step-over trees.

Photo courtesy of LHG Creative Photography/flickr.com

Photo courtesy of LHG Creative Photography/flickr.com

Weekly update for the fruit garden – third week of August 2015

Apples:

Today we picked some good sample of Discovery apples. During the first week of June, we thinned the clusters of the young fruitlets to two fruits per cluster. The effects of this are now, at picking time, very evident. The fruits are of beautiful colour, decent size and very crisp. It is always right with early maturing varieties to thin out the fruitlets, EARLY in the growing season, if you like crisp fruit with a good flavour. Never store early fruit with long term storage fruit. Early varieties produce lots of ethylene and therefore reduce the storage life of all the surrounding fruits.

Make a regular check and remove any fruits showing brown rot. Do not drop this fruit on the orchard floor. Spores easily spread and will infect other fruits still on the trees.

The rewards of a well-tended orchard

The rewards of a well-tended orchard

Raspberries:

Continue regular picking of the autumn–fruiting raspberries. Cut out the old canes of the summer fruiting raspberries. Tie in the new shoots.

Wasps, flies and over-ripe fruit

At this time of the year, wasps and flies can be a great problem with plums and cherries and later on with apples and pears. These insects are particularly interested when fruits are becoming OVER-RIPE.

Therefore do not delay in picking the fruits when ripe. Secondly, make sure local wasps’ nests are dealt with. Wasp traps are only partially effective. Clearing the nests in the vicinity is the best solution.

Photo courtesy of Ervins Strauhmanis/flickr.com

Photo courtesy of Ervins Strauhmanis/flickr.com

Pigeon damage on plums and greengages

Photo courtesy of Marle Hale/flickr.com

Photo courtesy of Marle Hale/flickr.com

It is at this time of the year, when the first newly emerging little leaves are a great attraction in all areas where pigeons are present in great numbers, where field rape is grown. The pigeons show a great desire to vary their food source. After having grazed the rape fields, the pigeons will move for a while to the nearest hedge cover. From that point they will attack any type of plum or green gage, severely damaging any blossom or young green leaves.

The net result is that the crop prospects of those trees will be set back greatly and may result in no crop at all. Anything that can be done to scare the pigeons away is worth trying. A mixture of various deterrents is better than just one. Click here to read about one method of protecting the trees.

The length of the period during which the trees are at risk will greatly depend on temperatures and type of weather. A long cold spell is the most damaging period. This season is likely to be a bad season as warm spring weather seems not to be expected just yet, according to the 10-day forecast by the weather experts.

Check now for honey fungus

Inspect your fruit tree area now for the appearance of the toadstools of aggressive fungi, such as Armillaria which can cause death to fruit trees. It is also called the honey fungus due to its warm brown colouring. If the toadstool has a collar it is most likely the honey fungus. There is no known cure. The only thing you can do is to remove the tree completely, including as many thick roots as possible. Do not plant a fruit tree in the same hole.

Now is also the time to think of planting extra trees for your garden. Choose from our tree variety list, and contact us for any questions!

Armillaria toadstools, photo courtesy of Tatiana Bulyonkova/flickr.com

Armillaria toadstools, photo courtesy of Tatiana Bulyonkova/flickr.com

Top ten tips for fruit trees in November

Scab on an apple leaf. Photo courtesy of keystonetree.com

Scab on an apple leaf. Photo courtesy of keystonetree.com

Taking in consideration the time of year and the current weather conditions, it is now that you can help the trees, in order to improve the crop for next year. Many fungal diseases have been more trouble than usual this season. The problem can be seen, for example, from black spots appearing on the leaves and on the fruit, or premature leaf drop or fruitlets not having made size and stopped growing, or that have dropped on the ground. I am referring to the serious effects of different fungi causing peach leaf curl, canker, scab, mildew, quince blight, walnut blight, coral spot, silver leaf and brown rot of fruit, just to mention the more common troubles. To eliminate or reduce the effect of these fungal diseases next season, the following measures should be taken within the next 10 days.

1) Spray the trees with Bordeaux mixture now and follow the instructions as stated on the container. Every good garden centre will stock Bordeaux mixture and is totally safe, if used correctly.

2) Use a good rake or a vacuum blower, which sucks up all the fallen leaves, affected by any of the fungal diseases as mentioned above. Destroy or remove the leaves from the fruit tree area, as fungal spores will overwinter on those leaves and will attack the tree and its fruit next year. Close mowing will pulverize the leaves. Provided the grass clippings and the shredded leaves are removed from the area, well away from the trees, this will also help.

3) Any dead wood in the trees needs to be removed and will have to be burned or shredded.

4) Any sizeable pruning cuts will have to be sealed with a sealing compound.

5) Canker wounds will have to cut out and painted with Arbrex or a similar healing compound.

6) Bacterial canker is not a fungus. However if the cherry and plum trees are not protected now, with the application of the Bordeaux mixture, the health status of the trees will seriously decline.

7) If you have had trouble with fireblight on pear trees, now is the time to cut out all infected branches cutting well back into healthy tissue, until there is no sign of staining. Burn the wood and seal the wounds.

8) If your peach trees have had serious trouble with the fungus called Peach leaf curl, apart from the measures as stated above, protect the tree with a plastic cover from late January until the middle of May. This will stop the spores already present in the trees from germinating. It is the rain that causes the spores to become active during the winter months.

9) When leaf fall is complete, say in about 10 to 14 days, repeat the application of the Bordeaux mixture on all the trees.

10) Dense tree canopies need to be opened up now by taking out large branches. This will improve the air flow through the tree canopy and reduce the incidence of fungal diseases. If you cannot throw your hat through the tree canopy then there is too much wood in the tree.