Pests and Diseases of Fruit Trees with Solutions to the Problems
Pests and Diseases of Fruit Trees with Solutions to the Problems
- 1 Pests and Diseases of Fruit Trees with Solutions to the Problems
- 2 Pests and Diseases of Fruit Trees: Fireblight
- 3 Pests and Diseases of Fruit Trees: Apple Blight
- 4 Pests and Diseases of Fruit Trees: Aphids
- 5 Pests and Diseases of Fruit Trees: Apple Scale
- 6 Pests and Diseases of Fruit Trees: Apple Tree Borer
- 7 Edible Landscaping — Edible of the Month: Asian Pears
- 8 How to Control Borers in Fruit Trees
Pests and Diseases of Fruit Trees: Fireblight
The pear, apple, and quince are liable to one mysterious disease which it is almost impossible to guard against or cure, the fireblight . Fire blight gets its name from the burnt appearance of affected blossoms and twigs. The disease still remains a disheartening mystery, and is more fatal to the pear than to the other fruits mentioned.
I have had thrifty young trees, just coming into bear suddenly turn black in both wood and foliage, appearing in the distance as if scorched by a blast from a furnace. In another instance a large mature tree was attacked, losing in a summer half its boughs.
These were cut out, and the remainder of the tree appeared healthy during the following summer, and bore a good crop of fruit. The disease often attacks but a single branch or a small portion of a tree. The authorities advise that everything should be cut away at once below all evidence of infection and burned.
To prevent fireblight you will fine that trees that are fertilized with wood-ash and a moderate amount of lime and salt, rather than with stimulating manures, will escape the disease.
If the ground is poor, however, and the growth feeble, barnyard manure or its equivalent is needed as a mulch.
Pests and Diseases of Fruit Trees: Apple Blight
Pests and Diseases of Fruit Trees: Aphids
The black and green aphids , or plant-lice , are often very troublesome.
sucking their juices check or enfeeble the growth. They are the milch-cows of ants, which are usually found very busy among them.
Nature apparently has made ample provision for this pest, for it has been estimated that «one aphid individual in five generations might be the progenitor of six thousand millions.»
Aphids are easily destroyed . Prepare a barrel of tobacco juice by steeping stems for several days, until the juice is of a dark brown color; we then mix this with soap-suds.
A pail is filled, and the ends of the shoots, where the insects are assembled, are bent down and dipped in the liquid. One dip is enough. Such parts as cannot be dipped are sprinkled liberally with a garden-syringe, and the application repeated from time to time, as long as any of the aphids remain.
The liquid can be so strong that it can damage the leaves; therefore it is better to test it on one or two subjects before using it extensively. Apply it in the evening.
8 More ways to Prevent or Treat Aphid Damage
|1. Encourage predators into your garden such as ladybirds, spiders and hoverflies.|
|2. Go easy on the nitrogen fertilizers as the softer growth encourages aphids.|
|3. Inspect vulnerable plants and break off and discard any affected pieces.|
|4. Plant pot marigolds and nasturtiums close to any plants you want to protect.|
|5. Spray affected plants with derris or very diluted washing-up liquid.|
|6. Hang up strips of fat in the trees to attract blue tits who love eating aphid eggs.|
|7. Use resistant plant varieties to start off with.|
|8. Burn or bury heavily damaged plants.|
Pests and Diseases of Fruit Trees: Apple Scale
Pests and Diseases of Fruit Trees: Apple Tree Borer
The apple tree borer is another very formidable pest, often destroying a young tree before its presence is known. I once found a young tree in a distant part of my place that I could push over with my finger.
In June a brown and white striped beetle deposits its eggs in the bark of the apple-tree near the ground. The larvae when hatched bore their way into the wood, and will soon destroy a small tree. However, you will soon see their evidence if you are observant.
Sawdust exudes from the holes by which they entered, and hopefully you are able to discover them before they have done much harm. I prefer to cut them out with a sharp, pointed knife, and make sure that they are dead; but a wire thrust into the hole will usually pierce and kill them.
Wood-ashes mounded up against the base of the tree are said to be a preventive. In the fall it can be spread, and makes one of the best of fertilizers.
Edible Landscaping — Edible of the Month: Asian Pears
Asian pears have a crisp texture like apples, but the flavor of a spicy pear.
Pears are a tasty fruit that mature in late summer and fall in most parts of the country. While we all love ‘Bartlett’, ‘Bosc’, ‘Clapp’s Favorite’, and many other European pear varieties, there’s a whole group of other pears from Asia that are becoming more available and popular to grow and eat.
Often called apple pears, Asian pears have characteristics of both fruits. Most Asian pears have a round shape, with the crisp, firm, texture of apples. However, inside they have a juicy white flesh and flavor reminiscent of pears. The fruits can have yellow to carmel colored, smooth or rough skin and a flavor with hints of cinnamon, apricot, and butterscotch, depending on the variety. There are hundreds of varieties in China, Korea, and Japan where these trees are native, and now they are becoming more readily available to American gardeners, too.
The beauty of Asian pears is they grow in USDA zones 5 to 9 and many varieties only grow 8-to 15-feet tall, making them perfect for a small yard. They are partially self-fertile so you can get away with just growing one tree, although two trees will produce more fruit. Some varieties have excellent resistance to common pear diseases, such as fire blight and bacterial canker. So consider a new fruit tree for your yard next spring. Do some taste testing of different varieties at your local market to decide which has the best flavor and grow a few Asian pears as a new treat.
Asian pears are hardy in much of the country, but certain varieties perform better than others depending on the geographic location and soil conditions. Most are sold as grafted varieties. Select varieties with root stocks adapted to your climate. For example, Pyrus ussuriensis rootstock is hardy to -40 degrees F and is a good choice for cold climates.
Harvest Asian pears when the fruits are still firm and have ripened to a sweet taste on the tree.
Like European pears, the fruit ripens in fall and some varieties can keep for months in storage. However, Asian pears must be harvested at the peak of maturity. Unlike European pears, they will not ripen further off the tree. Select at least two different varieties that mature at different times to extend the harvest season. Fire blight is less of a problem in hot, dry areas of the West Coast, so the options for varieties is expanded. Otherwise, select disease resistant varieties to limit the amount of spraying and pruning needed.
Here are some varieties of Asian pears to try in your yard.
‘Korean Giant’ (Dan Bae) – This vigorous tree will bear fruit at a young age. The tree is widely adapted across America and produces crisp, juicy 1-pound fruits with a high sugar content. It has excellent resistance to fire blight.
‘Ichiban» – This brown-skinned fruit has butterscotch-like flavored flesh. The fruits ripen early on this moderately disease resistant tree.
‘Nijisseiki’ – Also know as ’20th Century’ this is perhaps the most widely grown Asian pear variety. The yellow-green skinned medium-sized fruits have a sweet, yet tart flavor. This vigorous tree ripens in late summer, but is susceptible to fireblight.
‘Shinseiki’ – This partially self-fertile tree produces an abundance of medium-sized, yellow fruits in late summer. It has moderate resistance to fire blight.
‘Seuri’ – The large, dark orange-colored fruits have a flesh with the flavor of apricots. This low-chill variety is especially good for hot climates. It has good resistance to fire blight.
‘Yoinashi’ – A large-fruited, brown-skinned variety with a butterscotch flavor. However, while trees are somewhat disease resistant, they are susceptible to fire blight.
Select fireblight disease resistant varieties of Asian pears if this deadly bacterial disease is present in your area.
Plant trees in late summer or fall in mild winter climates, or spring in colder climates. When planting leave the graft union 3 inches above the soil line. Asian pears grow best in full-sun on well-drained fertile soils with a slightly acidic pH. Like European pears, Asian pears have an upright growth habit, so they can be spaced as close as 10 feet apart. However, for ease of working around them, it’s best to space trees 15 feet apart. Asian pears do respond well to espaliering on a wall or house if you are really tight for space.
Keep newly planted trees well watered. Once established Asian pears can be drought tolerant, but need moist soil conditions to get growing.
Water deeply at least once a week. Lack of water will result in smaller-sized fruits. Keep trees mulched and remove any grass or vegetation growing in the root zone. Fertilize in spring with compost and an organic tree fruit fertilizer. Don’t fertilizer too heavily with nitrogen. If your trees make more than 2-feet of new growth each year cut back on the nitrogen fertilizer. Too much new growth makes the tree more susceptible to fire blight disease.
Asian pears tend to set more fruit than they can support. When fruits are the size of a cherry, thin to one fruit per cluster spaced 6-inches apart. Prune Asian pears as you would European pears. Most are pruned to a modified leader system to encourage an open center and keep the branches from crowding. Prune in late winter to shape the tree and remove dead, diseased, or broken branches any time of year.
Diseases such as fire blight are the most prevalent problem on Asian pear trees. If fire blight is a problem in your area, select disease resistant varieties. If your tree does get fireblight disease, use sterilized pruners to remove the infected branch 1-foot below any signs of infection.
Insects pests such as codling moth can be controlled with dormant oil sprays in late winter and proper cleaning of dropped fruits and thinning of young fruits.
Harvest Asian pears when the fruit is still firm, but the background skin color has changed to the mature color for that variety. Mature trees can yield a few hundred pounds of fruit per tree. The best test for ripeness is tasting a few fruits. When ripe, the fruits will easily pull off the tree. Fruits that require a yank are probably not yet ripe. The skin and flesh are tender, so be careful to not bruise them when picking.
How to Control Borers in Fruit Trees
21 September, 2017
Borers are the larvae of certain moths and beetles that feed on the wood in trees instead of the leaves or fruits. Borers tunnel into the woody parts of trees, including the trunk, twigs, branches and even the roots. Borer infestations in fruit trees are difficult to control, and insecticidal sprays are only effective during limited times of the borer’s life cycle. Several other methods exist, however, to control borer infestations in fruit trees.
Look for signs and symptoms of a borer infestation. Study the fruit trees for tunnels that larvae have made in the trunk and limbs. Also look for dying branches.
Apply an insecticidal spray to the fruit trees once per month in the summer, following the application directions on the label. Use the insecticide only when the adult borers are active and laying eggs. The timing of insecticide use is crucial, because the insecticides won’t work on borer larvae, only on the adults and eggs.
Introduce biological controls to eradicate the borers. Trichogramma are small wasps that are parasites to more than 200 moth species, including borers. The wasps lay their eggs inside the borer eggs, and the developing Trichogramma feeds on the borer larvae.
Wrap the tree trunks with burlap or three layers of old newspapers. Wrap the fruit trees before the adult borers begin to emerge in the springtime. Make sure that you cover the tree from the ground to the lower branches and leave it on the tree for the first one or two seasons. Wrap any nearby young trees, even if they’re not infested, to prevent the adult borers from laying eggs on the bark.
Hand-worm the trees by digging the larvae out of their holes in the tree trunk and branches using a wire or knife. Look for the larvae in August and September. The larvae will be easier to find during this time, because the newly hatched larvae will cause sap to flow when they begin to feed. Seal the holes with tree paint immediately after removing the larvae.
Keep the fruit trees healthy and injury-free. Fertilize the fruit trees with an appropriate all-purpose granular fertilizer once per month to boost the trees’ strength. Water the trees once per week. If the tree is weakened by any other diseases, be sure to treat those as well.
Try pheromone traps to control peach tree borers, lesser peach tree borers and dogwood borers. You can also try whitewashing the tree trunks or painting them with a white, water-based latex paint to repel the adult moths or beetles.
Remove and burn any dead, weakened, infested limbs from the fruit trees. Always destroy the diseased wood that you’ve removed from the tree to prevent the pruned branches from becoming a breeding ground for the borers.
Although borers can attack healthy trees, they are more attracted to disease-weakened or injured trees. Be on the lookout for borer infestations if your fruit trees are weak from drought, disease or injuries.