Plum Fruit Tree Leaf Curl
Edward R. Forte
October 21, 2021
Q: My plum tree has leaf curl.These copper type sprays do not work to control aphid eggs that are overwintering.An aphid infestation in plum trees are indicated by tightly curled, deformed leaves, which are usually near the ends of new plum shoots in the spring.The leaf curl plum aphid can be seen if you unfold the curled leaves.Applications of pesticide this late in the spring can also be very detrimental to any beneficial insects that maybe working to help control the aphids.Once the leaves are curled on your plum tree they do not uncurl once the aphids are gone so it is best to give your tree plenty of water and nutrients so that it will grow new leaves that are not affected by the aphid to keep the tree healthy. .
Leaf Curl in Plum Trees
As well as the unsightly appearance of the damaged leaves, leaf curl plum aphids can cause malformed and stunted shoot tips.Managing the aphid population before the emerging leaves curl is key to preventing a heavy infestation without resorting to a chemical spray.Even if you don't have time for cultural controls, monitoring leaf curl plum aphid numbers tells you if you may need to spray later on.Inspect your plum tree in early spring before the leaf buds begin to open, and remove all the aphids you see.Simply blasting the aphids from the leaf shoots with a strong jet of water from a garden hose is effective at keeping population numbers low.On smaller trees you may be able to wipe off and crush the aphids manually, wearing gardening gloves if you find the job icky.Allow the soil surface beneath plum trees to dry out between waterings and only apply moderate amounts of fertilizer.Horticultural mineral oil is an effective dormant spray for treating leaf curl plum aphids.The best time of year for applying dormant spray to control leaf curl plum aphids is late fall or early winter, when the trees are losing their leaves.The best time to apply a growing season insecticide is before your tree blossoms or when the petals fade and fall.The insecticide active ingredients to be avoided include acetamiprid, carbaryl, esfenvalerate, gamma-cyhalothrin, imidacloprid, lambda-cyhalothrin, spinosad and zeta-cypermethrin. .
Plum and prune-Aphid
Pest description and crop damage Several aphid species attack plums and prunes, including the leaf curl plum aphid, hop vine aphid, and thistle aphid.Hop vine aphid ranges from green as wingless adults to near black as winged adults.The hop aphid overwinters as eggs in crevices and twigs on Prunus trees, the primary hosts.The eggs hatch in late March, and several generations of wingless females feed and reproduce on the plum/prune trees before the winged females migrate to the secondary host-hops-in May.Many secondary summer hosts of the leaf curl plum aphid and the thistle aphid are plants in the family Asteraceae, which include chrysanthemum, mayweed and groundsel.Pest monitoring Begin observing shoots prior to budbreak, as management is best undertaken early while aphid abundance is still low and before the emerging leaves begin to curl about and protect aphid colonies.Avoid broad-spectrum insecticide applications that disrupt the life cycles of these natural enemies.Apply with enough water to cover the entire tree thoroughly.Apply when overwintering eggs hatch during prebloom or petal fall.Summer applications should be before leaves curl.kaolin-Applied as a spray to leaves, stems, and fruit, it acts as a repellant to some insect pests.In summer, apply before leaves curl for best control.Fall sprays can provide excellent aphid control for the next growing season.REI varies; check product label.REI 4 days.Do not apply exceed 14 oz/a of Voliam Flexi per season. .
When to Spray Plum Trees for Leaf Curlers
| Pest Control.for leaf curlers varies depending on what is causing the leaves of the fruit tree to curl.One brand of Bordeaux mixture suggests mixing 12 tablespoons of the copper fungicide with 1 gallon of water to treat leaf curl and plum pockets.For best results, spray the plum tree during its dormant period between the leaf drop stage in late fall and the bud swell stage in early spring.Leaf curl plum aphids create honeydew, which is a sticky material secreted by the insects. .
Pests and Disease of Plum Trees
You may also notice one or two small hardened drops of resin on the fruit which are the tree's response to being attacked.In spring the sawfly emerges from the soil and lays eggs on the blossom of plum trees.The chemical deltamethrin sprayed when the blossom is falling off will definitely help control plum sawfly.Another effective method to control this pest is to break up and turn over the top 8cm / 3in of soil with a trowel around the tree in February to March.Plum trees are often attacked by aphids and the first signs are young leaves curling up, this is often referred to as.If you uncurl the leaf the aphids will be seen inside - small green, white or light brown insects.By themselves they probably won't cause too much damage but often they secrete a sticky juice which attracts unwanted diseases.This is caused by the caterpillar of the(Grapholita funebrana) and makes the fruit totally inedible.The lifecycle of this pest starts in May when the female moths lay eggs on the underside of growing plums.They then start to damage the new twig like branches, possibly simply because of the weight of the birds perching on them although some believe the pigeons peck at them.Either way the result is the same, leaves that are effectively destroyed and major damage to newly growing stems.The damage occurs typically in April to June time and the trees will fail to develop fruit in that year.Cut the bottom out of plastic bags and tie loosely to branches - unattractive maybe but it seems to be the most successful way to scare pigeons.Plastic model of birds of prey tied high up on the tree and moved occasionally.One method which has been proven to be a failure is to try and attract the pigeons to other areas of the garden / allotment with bird food.What then happens is that more pigeons are attracted, they eat the bird food and then turn their attentions to the tree.Most at risk are plum trees that bear fruit very closely together (Victoria plum trees are particularly prone to Brown Rot) There are no chemical sprays available to the amateur gardener but if you follow the action plan below this disease can be eradicated:.With trees of this size the plum fruit higher up cannot be harvested and is a prime target for Brown Rot.Too much fruit causes them to rub together allowing fungi such as Brown Rot to enter, it also prevents good air circulation.If you can identify the period in May /June when the young scale insects are on the move spraying with an insecticide will kill them.If you miss this stage of their lifecycle then a plant oil winter wash treatment (again ask at your local garden centre) in December to January will effectively suffocate many of the overwintering bugs.The easiest method, if your tree is a manageable size, is to manually remove the scale insects around May when they are clearly visible but have not yet hatched their eggs.If the fruits are cut open at any stage no stone will be found, just an empty "pocket" of white flesh as can clearly be seen from the picture above.The disease is caused by the fungus Taphrina pruni and affects plum and damson trees.It is more commonly found on wild plum and damson trees so if you have any nearby take a careful look at them for signs of infection.The spores become airborne in early spring, land on your tree and lodge in the bark and newly forming branch buds.They then multiply and begin to attack fruit buds and young fruit and cause the damage mentioned above.The spores of the fungi are spread through air and water from nearby infected trees and also from the affected tree itself.Treatment is aimed at limiting the spread of the spores and at the same time spraying the tree before fruit buds form in early spring.The first course of action is to remove and burn all affected fruit including those which have fallen to the ground.Take a close look at the tree and if you notice any unusually thick clusters of twigs growing from branches, prune them off because in all likelihood they are infected.The best one we know of for Plum Pocket is Westland Plant Rescue Fungus Concentrate, the active ingredient is Difenoconazole.The copper fungicide Bordeaux Mixture has previously been recommended as a spray to prevent Plum Pocket.Where the disease is left to progress secondary infections and pests may well attack the weakened tree.Aphids in particular (please use a magnifying glass to examine the leaves) are attracted to weakened trees and they may cause the mildew to turn sticky in places.Read our detailed article to positively identify Silver Leaf disease, the causes and how to treat it.Less obvious signs are brown marks around developing buds and / or grey spots on the fruit which may also include a resinous gum.The copper fungicide Bordeaux Mixture has previously been recommended as a spray to prevent fungal diseases in fruit trees.The fungus can also be controlled simply by reducing the number of affected leaves, buds and correct pruning especially of the lower parts of the centre of the tree.Plum trees such as Victoria are more likely to be affected by Shot hole because they tend to grow branches and foliage close together - perfect conditions for this fungus.The adult beetles (black / dark brown) bore small holes into the wood in May / June time where they lay about 50 eggs.About two months later the larvae have turned into adult beetles and they bore their way out of the wood leaving the characteristic small round holes.In most cases plum trees which are affected are already weak and the shot hole borers cause even more damage.In the UK there are no insecticide / pesticide sprays to prevent or cure shot hole borers.Rust thrives in humid conditions and this can be minimised by ensuring there is good air circulation through the middle of the tree.Plum tree rust primarily overwinters on leaves which have fallen to the ground.Leaves infected with rust are still capable of supplying nutrients to the plum tree especially just before they fall off.Click here to read our detailed article about identifying and treating bacterial canker as well as the lifecycle.Plum trees which suffer from environmental stress such as hot or cold weather, fluctuating levels of moisture at the roots or similar conditions often produce plums which have small blobs of clear and hardened liquid on them, the picture below shows these blobs on plums.As well as environmental conditions this can be caused by very localised insect damage or it can be the result of some other more serious pest or disease.To save some time for many of you reading this, I can confirm that the two most common plum trees, Victoria and Czar, are self-fertile and do not need a pollination partner to set fruit.In other areas the weather may have been too cold or too windy / rainy for a prolonged period of time which will prevent bees going out and pollinating the tree.With smaller trees and those in containers it is possible to net them with horticultural fleece to reduce the risk of frost damage.Typically there will be a dry period and during this time the forming plum skin will start to harden slightly as a result.Then, if there is suddenly a large amount of water available the fruits will swell but the skin can't keep up with it and splits open.If a tree is starved of water eventually it will suffer and wilting leaves will be one of the first indications of a problem.Where the tree is in a container, temporarily moving it to a shady position as well will speed up the recovery process.If the canker only affect specific branches, the wilting leaves will be restricted to that part of the tree.There have been many contraptions and devices developed over the years but, so far, the evidence is that none of them has any significant effect in reducing wasp activity.This includes jam jars full of sugary liquid which can trap a few wasps but the numbers are so insignificant that they can be considered useless.Wasps are not lazy insects but neither are they stupid, they build their nests near to a source of food and they consider plums, apples, pears etc.Apologies for not providing a quick and free solution to wasp damage on plum and other fruit trees, but the above are the facts.If the leaves of your plum tree have significant damage to them and there is no sign of caterpillars or other bugs then the most likely cause is the.There are several birds of prey plastic models which can be hung in trees that are designed to scare them off.Other solutions involve hanging CDs or plastic bags in the branches but these also appear to fail. .
Bill Pramuk, Trees and People: The elusive cause of plum leaf curling
It is a condition I must have seen a thousand times over the years, starting at the front desk at the garden center I was working in back in the late ‘70s and early ‘80s.People would bring in a few puckered and curled plum leaves and say their tree had “curly leaf” and ask what they should do about it. .
Peach Leaf Curl
Cells of the fungus break free from the outer surface of the leaves and produce asci (sacs), which release ascispores (sexual spores).After sickened leaves fall, fresh ones will grow in their place that will either be healthy or become infected, depending on weather conditions.Most peach varieties are susceptible to leaf curl, and the few that are resistant are not highly regarded in terms of fruit quality.If your peach trees are severely afflicted by leaf curl, a single, well-timed application of fungicide is often sufficient to restore health. .