How to get rid of woolly aphids?

Woolly Aphids: Tips For Woolly Aphid Treatment

Although woolly aphid populations rarely get large enough to harm most plants, the distorted and curled leaves they cause and leave behind can certainly become unsightly. For this reason, many people prefer to use some type of woolly aphid treatment to care of these pests.

What are Woolly Aphids?

Much like other types of aphids, these sap-sucking insect pests are small (1/4 inch). However, woolly aphids, which are green or blue, also appear fuzzy due to the white, waxy material that covers their body. These pests generally use two hosts: one for overwintering and laying eggs in spring, and one for feeding in summer.

Woolly Aphid Damage

Woolly aphid insects generally feed in groups. They can be seen feeding on foliage, buds, twigs and branches, bark, and even the roots. Damage may be recognized by twisted and curled leaves, yellowing foliage, poor plant growth, branch dieback, or the development of cankers and gall on limbs or roots.

Wax accumulation is sometimes seen as well, along with the sweet, sticky residue known as honeydew.

In addition, plants may become covered with sooty mold, an unsightly black fungus that resembles soot. Though this does not normally affect or damage the plant itself, getting rid of the aphids and their honeydew will help control the sooty mold.

Woolly Aphid Control

Since severe woolly aphid attacks rarely occur, there is little need for woolly aphid pesticide for control. Generally, their numbers are kept low with natural predators like lacewings, ladybugs, hover flies, and parasitic wasps.

If desired, you can spot treat where the aphids are most abundant using insecticidal soap or neem oil. You can also prune out and destroy infested branches when feasible. When chemical control is deemed necessary, woolly aphid insecticide such as acephate (Orthene) can be used to control these pests.

“Sir, this is a very serious operation, we’re trying to save lives here and we need you to stop dancing like that immediately.”

“Nope, too late. Look at this hip movement. Look at it. You don’t want to mess with this. Did someone say limbo?”

“No one said lim–“

“You know, we should really rethink our defensive strategy because if I see one more Hawaiian shirt while we’re in the middle of a crisis–“

“Conga line!”

****

Commonly known as woolly aphids, these fuzzy little guys are distinguished by the long, white, waxy filaments that cover their posteriors. Not to be confused with the woolly aphids from the Eriosomatinae family, which terrorise apple trees under an expansive blanket of white fluff, these are beech blight aphids (Grylloprociphilus imbricator), a species that lives off the sap of beech trees in North America.

A population of beech blight aphids will settle onto a beech tree, amassing by the thousands across its branches like freshly fallen snow. Here they’ll pierce the bark with their syringe-like mouthparts called stylets and suck the sap out. Their calling card is a dark, ugly build-up around the tree caused by sooty mold fungi (Ascomycete), which turn aphid excretions called honeydew black while extracting the nutrients. Despite the worrying appearance of this thick, black tar, these aphids are not considered a serious threat to their beech tree hosts – at the very worst they might distort or slightly stunt the growth of the leaves or kill off a small branch.

(This video confuses beech blight aphids with woolly beech leaf aphids (Phyllaphis fagi), but it’s too great not to use. Unlike G. imbricator, which are found primarily on branches and twigs, P. fagi stick mainly to the undersides of leaves.)

Known affectionately as the ‘boogie-woogie aphid’, when a colony of beech blight aphids is disturbed, they’ll lift their fuzzy posteriors high in the air and pulse them in unison as a warning to predators. Sort of like the black lace-weaver spiders, which when young, will gather together in a group of 160 siblings and contract their bodies to make their web throb in response to a predator. Watch a video here.

A 2001 study led by biologist Shigeyuki Aoki from Rissho University in Japan discovered that, like the black lace-weaver spiderlings, it’s the beech blight aphid nymphs, not the adults, that respond to predators. When the researchers introduced a number of predatory moth larvae to colonies of G. imbricator, aphid nymphs of all stages (or instars) of development would raise their posteriors and walk around, waggling their abdomens back and forth. Those in the middle of feeding would simply waggle themselves on the spot.

And this was no false warning. These nymphs were young, but they were also aggressive. “A total of 69 nymphs attacked the ten tortricid larvae, and 47 of them did not detach themselves from the larvae even after being deposited in ethanol. We ascertained under a dissecting microscope that many of them, including nymphs of all four instars, stung the larvae with their stylets. We confirmed the stinging behaviour by placing some aphids on our hands,” the team wrote in their The Florida Entomologist paper. “In this species, nymphs of all four instars played a defensive role, but 4-instar nymphs were the main defenders.”

So less sweet fairy jig and more menacing war-dance performed by children.

You can read more about the black lace-weaver spiderlings – also encouraged by their very own mum to eat her alive before venturing out of the nest – in my new book, Zombie Tits, Astronaut Fish and Other Weird Animals. Pre-orders get a discount, so .

Wooly apple aphid, Eriosoma lanigerum (Hausmann) (Homoptera: Aphididae), damage to apple roots. Photo by J. W. Stewart.

Common Name: Wooly apple aphid
Scientific Name: Eriosoma lanigerum (Hausmann)
Order: Homoptera

Description: Aphids are reddish-purplish, wingless or winged and covered with woolly, bluish-white wax masses.

Several other aphid species (Paraprociphilus spp., Eriosoma spp., Stegophylla spp.) produce large quantities of woolly wax filaments and infest leaves of alders, elms and oaks. At certain times during the summer, infestations can become noticeable on host plants such as Arizona ash in central Texas. Masses of woolly aphids infest the undersides of leaves on terminal growth, causing leaves to turn pale green and curl.

Life Cycle: Simple metamorphosis; parthenogenic. Winter is spent in the egg or young nymphal stages underground in root galls, and as adult egg-laying females on the branches and trunks of host plants. Eggs are laid in bark cracks on elm in the fall and hatch in early spring. Wingless nymphs feed on new growth and twigs for two generations (May and June), producing winged forms that fly to other host plants (apple, hawthorn and mountain ash). There, they feed on wounds on trunks and branches and move to the root zone. In summertime, females give birth to live young (parthenogenesis). Wingless males are produced in the fall and mate with wingless females, each of which lay a single overwintering egg.

Habitat and Food Source(s): Aphids become noticeable because of the woolly wax masses on wounds of the trunk and branches on apple, elm, hawthorn, mountain ash, pear and quince. Underground, aphids cause large knots on roots on apple trees. Heavily infested trees become stunted and may die. Rootstock of all but a few apple varieties is susceptible to attack. Woolly apple aphids have become a problem in areas of Texas where dwarf apple varieties have been planted using susceptible root stock. Aphids can be preserved in alcohol, although the waxy masses will dissolve. Waxy masses can be preserved by freezing infested leaf specimens and storing them dry in a vial or small box.

Pest Status: Occurs on apples with susceptible rootstock or susceptible varieties; medically harmless.

For additional information, contact your local Texas A&M AgriLife Extension Service agent or search for other state Extension offices.

Literature: Johnson & Lyon 1988; Metcalf et al. 1962.

Woolly aphids

Description of woolly aphids

Woolly aphids live on several different trees and shrubs. The name describes what is peculiar about this group: The body of the aphid is covered with a white fluffy wax that resembles wool. In late summer you may notice colonies of woolly aphids clustered on the twigs and shoots of hawthorn and crabapple trees. Infestations are sporadic and vary from trees to tree, variety to variety and place to place.

Damage caused by woolly aphids

Woolly aphids on hawthorn and crabapples feed on sap from the plant but are more alarming than damaging, especially late in the season. Earlier in the season there were woolly aphids of another species on the leaves and shoots of maple trees. In most cases the sap loss from aphid feeding is not significant to the plant and control is not practical. In some cases infested leaves may droop or shrivel and drop prematurely. This does not reduce the vigor of healthy trees.

Management of woolly aphids

Parasites, predators and even heavy rainfall will help reduce the populations. If you believe the natural population controls need your help you can use a forceful stream of water from the garden hose to dislodge the aphids or prune and remove selected, heavily infested stems and water sprouts. Spraying with insecticide is rarely justified.

Do you live in Iowa and have an insect you would like identified?

The Iowa State University Plant & Insect Diagnostic Clinic will identify your insect, provide information on what it eats, life cycle, and if it is a pest the best ways to manage them. Please see our website for current forms, fees, and instructions on preserving and mailing insects.

Contact information for each states diagnostic laboratory for U.S. residents. If you live outside of Iowa please do not submit a sample without contacting the Plant & Insect Diagnostic Clinic

Aphid: Woolly apple aphid (WAA)

Overview

WAA is a reddish brown aphid covered with a white wax mass produced by specialized dermal glands. This wax mass gives the insect its characteristic woolly appearance. WAA have a complex life cycle that can involve overwintering either on apple or elm. Once on apple they move to feeding sites on roots or above ground. Root feeding produces knotty galls, and extensive feeding severly taxes the root system. Unfortunately, the above-ground WAA population is not a reliable indication of the root-feeding population. Above ground, crawlers settle in bark crevices, pruning cuts, wounds, leaf axils, and occasionally the stem or calyx of fruit. Black sooty mold fungus can develop on WAA honeydew.

Biology

  • WAA overwinter as eggs on elm trees. In early spring, wingless females remain feeding on elm for 2 generations. Winged females are then produced and migrate to apple trees late in June.
  • Once on apple, ‘crawlers’ are produced that spread throughout the tree. Several generations are produced on apples each summer. Large nymphs have a purplish body, concealed by tufts of “wool”, which are actually fine wax strands.
  • In the fall, winged forms are again produced that migrate back to elm and deposit overwintering eggs.
  • Colonies can persist on apple roots throughout the year.

Monitoring

  • Monitor for WAA in mid-late summer when, if present, colonies of nymphs or adults become most visible.
  • Because of poor coorelation of above and below ground populations, there is only a tentative treatment threshold of 50% of pruning wounds. Sample 10 possible infestation sites per tree on at least 10 trees per block.
  • Should WAA infestations appear on substantial numbers of leaf axils of terminals or fruiting spurs, treatment may be warranted to reduce possible injury to developing buds.

Management

  • WAA are resistant to many commonly used insecticides. Apply an effective insecticide in summer if warranted.
  • Best control is obtained when insecticide is applied in July when small WAA colonies appear on periphery of canopy, but this is before colonies are easily visible.
  • Some insecticides can be applied to soil to manage WAA infesting roots.

Woolly Apple Aphid

Woolly apple aphid is a serious pest of apples, particularly young trees. Colonies form at wound sites on trunks, limbs, and twigs, where they feed on tender bark. Pruning and hail damage can create the wound sites for attack by this pest. Egg-laying wounds by the periodical cicada are ideal sites for infestation. As populations grow, aphids are commonly found on water sprouts in the center of the tree. The tree will begin to swell and form galls at the feeding sites.

As the number of aphids on the above ground portion of the tree increase, many work their way down to the roots and trunk below ground surface. It is the feeding on the roots that produces the greatest damage. Mature trees usually suffer little damage from the root infestations, but the root infestations are very damaging to young trees. Control of these aphids is very difficult when they attack the roots. Yellowish foliage is a sign that woolly apple aphid may be infesting roots. The root systems of nursery stock can be damaged, and severe root infestations can stunt or kill young trees. Infested trees often have short fibrous roots, which predisposes them to being easily uprooted. Swollen galls also form on roots; galls increase in size from year to year and are sites where fungi can attack. Aphid feeding on the root systems also disrupts the nutrient balance of root tissue, which can affect growth of other parts of the tree. Trees can have above-ground infestations of woolly apple aphid but no root infestations. Rootstocks vary in susceptibility to woolly apple aphid and susceptible rootstocks will form galls around the infestation sites. Use M111 or M106 if woolly apple aphid is a serious problem. Rootstocks appearing more susceptible to woolly apple aphid infestation include B9, M9, M26 and the P series.

During the summer, repeated woolly apple aphids generations of wingless individuals are produced. In the fall, winged individuals are produced which fly to search for elms on which to lay overwintering eggs, while some wingless forms may remain on both above and below ground parts of the apple tree throughout the winter.

Figure 2. A colony with the wax removed to reveal the live pinkish-purple aphids.

Woolly apple aphid colonies produce honeydew, which results in development of black sooty mold. The wax and the honeydew are bothersome to pickers when it brushes off the tree and onto clothing of pickers.

It is relatively easy to find where the colonies have formed. When monitoring for woolly apple aphid, examine four pruning scars on each of 5 scaffold limbs per tree. Carefully examine woolly apple aphid colonies to determine if live aphids are present. Predators, such as lady beetles, hover fly larvae, and lacewing larvae can completely destroy the colony, but the waxy residue will remain. When examining colonies, blow hard on the branch to remove the waxy filaments to reveal live aphids. Treatments for woolly apple aphid are recommended when 10% of the pruning scars are infested with live colonies.

Figure 3. A hover fly larva feeding on woolly apple aphids.

There are few insecticides specifically labeled for control of woolly apple aphid. Diazinon, Closer, Beleaf, Movento, and Admire Pro are recommended for control of above-ground infestations. There are no insecticides to control root infestations on bearing apple trees.

Revised: 11/19

Ministry of Agriculture, Food and Rural Affairs

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Woolly Apple Aphid Management

The woolly apple aphid (WAA), Erisoma lanigerum has historically been considered an occasional apple pest in Ontario, but is now seen more frequently in orchards. Besides apples, other hosts include pear, hawthorn, mountain ash and elm.

There can be two colonies of WAA: aerial and underground (on roots). While aerial colonies are well established, it is debated whether underground colonies are an issue in Ontario or if the winters are too harsh for survival. There are few reports of WAA impeding root development.

Aerial colonies overwinter as eggs in bark cracks and crevices (Figure 1). In the spring, nymphs migrate up to apple shoots and tender bark areas. Colonies covered in a white, waxy coating are typically first observed in June on pruning cuts (Figure 2), around wounds of limbs and trunks and at the base of young shoots. As the summer progress, infestations increase and spread to growing twigs and leaf axils of water sprouts (Figure 3).

Figure 1. Aerial colonies of woolly apple aphid overwinter as eggs in bark cracks and crevices.

Figure 2. Woolly apple aphid colonies can be first observed in June on pruning cuts.

Figure 3. As summer progresses, woolly apple aphid colonies spread to growing twigs and leaf axils of water sprouts.

Crawlers can move to roots any time they are active, mainly in June and July, and in the fall. There are winged aphids, and crawlers, and both move from tree to tree. Close tree spacing and clean, smooth soil surfaces favour crawler migration. High soil temperature, weed cover and larger tree spacing inhibit movement between trees.

Woolly apple aphid feeding forms knots or galls on twigs (Figure 4) or roots. This can lead to stunting of new growth, especially on young trees. Areas damaged by WAA are also more sensitive to frost and winter injury. Where canker disease has established, aphid feeding may spread the pathogen.

Figure 4. Woolly apple aphid feeding forms knots or galls on succulent growth.

Similar to other aphids, WAA excrete a sticky material called honeydew that drips on fruit and leaves. Honeydew causes russet spots on the fruit. A black, sooty fungus may establish on the honeydew, downgrading fruit quality. Honeydew is also a nuisance to harvesters because it is sticky and stains cloths on contact.

Ideally, Aphelinus mali, a parasitic wasp can completely control aerial colonies of WAA. Parasitized aphids appear as black mummies (Figure 5). Unfortunately, A. mali are very sensitive to many commonly used insecticides in conventionally managed orchards (Table 1).

Figure 5. Woolly apple aphid parasitized by Aphelinus mali appear as black mummies. (Photo: E. Beers, WSU)

Table 1. Toxicity of commonly used insecticide groups to Aphelinus mali

Group Group Name Toxicity to A. mali
1A Carbamate VT
1B Organophosphate VT
3 Pyrethroids VT
4A Neonicotinoids MT – VT
5 Spinosyns MT
28 Diamides NT – MT

VT = Very toxic; MT = Moderately toxic; NT = Not toxic

Interestingly, research has been done in Washington looking at the use of flowers planted down the middle of every alley to promote aphid suppression in orchard systems (Gontijo et al., 2013). Aphid densities were found to be significantly lower on trees adjacent to flowers than those on control plots. In particular, a diverse group of generalist-predator spiders and insects including syrphid flies increased significantly near sweet alyssum (Figure 6). The alyssum could then be mowed throughout the season or mowers were adapted to leave the center strip uncut.

Figure 6. Sweet alyssum planted between rows of apple trees can reduce woolly apple aphid colonies by enhancing natural enemy habitat. (Photo: Good Fruit Grower)

Other management strategies include:

  • Resistant rootstock – Malling rootstock series with numbers over 100 are generally resistant (MM.106, MM.111) as well as G.41 and G.202. However, resistance is not passed on to scion and does not impact the aerial population.
  • Chemical control – There are no chemical controls for underground infestations. Apply registered insecticide sprays when aerial colonies first start to appear. Early summer management is more effective than later summer controls as the waxy covering over these pests is less and easier for insecticides to penetrate. Field observations of Movento applied at petal fall for apple leafcurling midge and again 14 days later provided good control of WAA. Aphids were also controlled well in San Jose scale trials using Closer when the high rate of 400 mL/ha was used. Reports from New York (Agnello, 2017), Pennsylvania (Biddinger, 2017) and Washington (Beers et al., 2007) suggest similar findings.
  • Cultural control:
    • Monitor suckers and pruning cuts between petal fall and 1st cover.
    • Remove root suckers to eliminate early colonization sites.
    • Remove water sprouts on major scaffold limbs early in the season (June).
    • Paint large pruning cuts to discourage colonies.
    • Remove larger colonies during summer pruning.

Agnello, A. 2017. The Usual Suspects: A Reprise by San Jose Scale & Woolly Apple Aphid. Presented at Ontario Fruit & Vegetable Convention, Niagara Falls, ON.

Biddinger, D. 2017. Orchard IPM – BMSB and Woolly Apple Aphid.

Gontijo, LM., Beers, EH. and Snyder, WE. 2013. Flowers promote aphid suppression in apple orchards. Biological Control. 66:8-15.

How to identify live aphids

Robert D. Dransfield, InfluentialPoints

Feedback & comments

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  • Nigel Gilligan 10 Jan 2014

    I have just been informed about the Influential Points web site, with the extensive pages on aphids. I have many macro photos of aphids, but due to the difficulty of getting an ID, I’ve generally only taken them out of curiosity, rather than an expectation of getting a name down to species level. Can you advise me as to the practicality of using these pages to identify from photos alone – I have no specimens. Or is it more for guidance when identifying from a specimen?

  • Bob Dransfield InfluentialPoints.com 10 Jan 2014

    It is certainly our intention, as photos get better, to be able to identify an aphid down to species level from a photo. After all we no longer have to shoot birds in order to identify them, albeit it used to be considered essential! But there are two important provisos: The first is that you need to know the plant (preferably species) that the aphid is on in order to narrow down the choices. The second is that you must have of photo of an adult aphid – not an immature (fairly easy in some species, infernally difficult in others). If these two provisos are met, then you do stand quite a good chance of identifying the aphid from our site – assuming of course the photo is sufficiently good (you don’t have to spend a mint on gear for this, although some do). All sorts of things can also help – especially pictures shot from different angles and targeted at key characteristics. Being able to recognise common – and distinctive – species helps. Note: some species are much easier to recognise live than pickled but, if you want to get serious, a second-hand microscope allows you to do lot with ordinary ‘wet’ specimens in propanol / ‘rubbing alcohol’. We know a number of people are now using our site for identifying live (and preserved) specimens, and we are very ready to assist – although please try to identify them from the site first, and then check with us for ‘confirmation’. We’re also keen to put good photos from other people on our site – but only if they give approval first. Lastly, we always appreciate acknowledgment of assistance in identification if you use the photo on your own website.

  • Nigel Gilligan 11 Jan 2014

    That sounds like quite comprehensive advice – thanks very much. Reviewing my old aphid photos, I see that I will have to up my standards. I have a tendency to forget to log the plant species when taking photos of certain groups of insects, such as heteropteran and homopteran bugs. It’s a useful guide when identifying this family too, but subsequently trying to ID a plant when I only have a set of cropped images is a job that even a plant expert would probably fail at. Another problem is that a large number of my aphids were shot when walking across walls and other non-plant surfaces! I don’t know why this is – I don’t have a bias, as far as I know. I think, in summary, I might manage to ID a few of my species, but at the moment I’m giving my priority to trying to finalise my 2013 records for formal submission. Aphids will have to be done in my marginal time!

  • Blackman, R. L. & Eastop, V. (2000). Aphids on the World’s Crops. 2nd Edn. Wiley, Chichester, 466 pp.

Identification requests

David Fenwick, 4 August 2013, Aphid on Pine

Aphid on Scot’s Pine, in the middle of a small pine wood near Marazion. Only one present!

Images copyright www.aphotofauna.com all rights reserved.

Bob, Influentialpoints:

  • Probably an incidental from another tree, I cannot think of anything on pine like this.

David Fenwick, 4 August 2013, 2 Cavariella on Hogweed

Wondering if I have both Cavariella pastinacae and Cavariella theobaldi here on Hogweed.

Image copyright www.aphotofauna.com all rights reserved.

Bob, Influentialpoints:

  • Maybe, but you need adults to separate the species- and both of these are alatiform IV instars.

Dr Wagner, 30 March 2014, Unidentified aphid?

On my first excursion I found an animal, about 2-3mm on a leaf. At home I tried to identify it and came to the conclusion that it might be an aphid but I am not really sure. So I ask Your help. As You see, macro-season is starting early this year.

Image copyright Volkmar Wagner

Bob, Influentialpoints:

  • It’s not an aphid but a psyllid (related group of Homoptera). Superfamily Psylloidea; Familly Triozidae.

    The most likely species is Trioza remota (oak psyllid). It has fairly amazing nymphs (picture attached) which you can look out for on oak leaves.

Image InfluentialPoints.

Dana Black-Boyd, 10 May 2014, Aphid? Found on my back porch near fire cracker plant. Bradenton, Fl

Image copyright Dana Black-Boyd, all rights reserved.

Bob, Influentialpoints:

  • IF the insect you photographed is an aphid from your firecracker plant (Cuphea ignea), it is most probably one of the five species of Impatientinum that live on Cuphea species in South America (Mexico, Panama and Brazil).

    Those aphids are fairly large (up to perhaps 1/4 inch long) and brightly coloured, with long black siphunculi. (Siphunculi are 2 tubes on the aphid’s back, one on each side, near to its rear end.)

    Only aphids have siphunculi. In most aphids they are very prominent – but a few aphid species have very small siphunculi (or just 2 pores, or none at all).

    Unfortunately the photograph you sent us did not show enough detail to see any siphunculi – or other key diagnostic features – so we cannot say if your insect was an aphid – but, if you have good eyesight or a hand-lens, you may be able to answer your question for yourself!

    If you are unsure what to look for, see (The first aphid shown on that page has short dark cone-shaped siphunculi, and wings.)

    Sorry we could not give you a simpler answer – hope this helps a bit.

Steve Nanz 17/10/2014

This looks like a first or second instar Coreid bug.

Bob, Influentialpoints:

  • Many thanks for that.

    As you may have gathered from the phrase “IF the insect you photographed is an aphid” we were very unconvinced that it was a homopteran – it did indeed look like like a heteropteran.

    But, since we seldom deal with the American Heteroptera, we decided not to hazard a guess.

Alan Outen, 13 May 2014, Woolly creatures on Alder

The main reason for this mailing is a woolly creature that I found on Alnus glutinosa (Common Alder) beside the River Ivel. I have returned this morning and collected more. The woolly appearance of these initially looked to me very like on-line images of Prociphilus or Paraprociphilus tessellatus, though all the websites dealing with this appear to be American and I can find no reference to it on your site, in the old Kloet & Hincks checklist or other British websites etc. as actually occurring in Britain! Furthermore when I look closely at the insects themselves they look very different and rather unlike aphids, though they were in some cases attended by ants. It rather looks therefore as if something else on Alder may have solved a similar problem in a virtually identical way to the Woolly Alder Aphid! Other than the fact that they look more like nymphs of something I have no idea now what they might be!

There is an image of something that DOES look identical to my species, again from North America at bugguide with the question “Woolly Alder Aphid??” Unfortunately it would appear that nobody has provided him with an answer!

As it is not inconceivable that you will have encountered these when looking for aphids I wonder if you might perhaps have any suggestions regarding their identity.

I have taken a large number of images and append some below. On the tree they looked very static but the insects are remarkably mobile once bits of Alder wih them on are collected. (I do incidentally find this also happens with a lot of aphids, with those in massed aggregations often quickly dispersing).

Images copyright Alan Outen, all rights reserved.

I think I have cracked this one and that these are nymphs of the Alder Psyllid (Psylla alni). Adults of this species are often common at this site but interesting how closely the woolly waxy secretions resembel those of a North American woolly aphid!

Bob, Influentialpoints:

  • Yes they are indeed Psylla alni. The nymphs are rather fascinating and we’ve often found quite large colonies.

Dr Wagner, 22 May 2014, Aphid on apple-leaf

Today I have controlled our apple-trees and discovered two aphids, one adult and the other possibly a baby-aphid. The bigger one had about 2-3mm the small one 0,5-1mm. I appreciate your help.

Image(s) copyright V. Wagner, all rights reserved.

Bob, InfluentialPoints:

  • Neither are actually aphids, but both are still interesting!

    The first is an adult psocid (order Pscocoptera) sometimes called barkflies.

    I’m not up on identifying species in this group, but pictures and info are here and here.

    The second is an immature psyllid (Psylloidea), probably a Cacopsylla species.

    Pictures and info are here.

Alan Outen, 4 June 2014

I have two queries dating from the beginning of May, though I think both of these are the same thing.

On Raspberry leaves in our Clifton garden, 01 May 2014. The final one looks as if it is again the victim of Entomophthora attack.

Image(s) copyright Alan Outen, all rights reserved.

On Gooseberry leaves from same site and on the same date what would appear to be the same species heavily infected with Entomophthora.

I had intended following up on these but when I looked again a week later there were only dead remnants on both host species. Isuspect though that this is again the genearlist Macrosiphum euphorbiae but would be grateful for confirmation.

Then today on Birch tree on our road verge I think the same thing again, alates with legs, antennae and body all very long. Assuming these are all correct then I think I have probably cracked this one now!

The final two here are rather more interesting I think.

Bob, InfluentialPoints:

  • Re raspberry aphid and birch aphid, I suspect you’re suffering from a slight attack of Macrosiphumeuphorbeitis… – defined as concluding everything is that species simply because it does on occasion seem to turn up everywhere.

    The one on raspberry is possibly M euphorbiae, but also check Amphorophora idaei.

    The goosebery one I’m not sure about.

    The one on birch is not M. euphorbiae but a Euceraphis sp. – it has short siphunculi.

Apologies also for bout of Macrosipumeuphorbeitis. I will be on my guard for this but was I think getting a bit overwhelmed by these and a host of other things that I should actually have been getting on with!!

I will check out the one on Raspberry again.

Aphids, mealybugs and scales

Aphids, mealybugs and scales appear on plant parts in clusters and feed on the sweet sap by inserting a needle-like sucking tube into the plant and drawing out the juice. After the sap has been used by the insects, it is excreted as honeydew, which forms the base on which a black fungus grows. This fungus is known as sooty mould and its presence reduces photosynthesis and discolours affected fruit.

Honeydew is used as a food source by ants, which actively transport the insects (aphids, mealybugs and scales) and position them on the plant.

Ants may spread sapsucker infestations between plants via underground tunnels.

As aphids, mealybugs and scales congregate in hidden places, or on the lower leaf surface, they may initially not be obvious. Affected plants appear water-stressed and leaves turn yellow and fall. In some cases leaves and flowers curl up and wilt.

Aphids, mealybugs and scales all have the potential to transmit viruses between plants. However, aphids are the most likely transmitters.

Aphids

Most aphids are soft bodied, pear-shaped insects, 1-2mm long, which prefer feeding on tender growing shoots. In Western Australia, most aphids are females which are able to give birth to living young without the need to mate. Reproduction is fast when weather conditions are favourable, leading to a rapid build-up and aphid population outbreaks. Cold conditions slow their rate of development and movement. Normally, the whole family will be found feeding together.

Blue-green aphid

The young aphids (nymphs) go through several growth stages, moulting at each stage. Nymphs do not have wings. When conditions are favourable and aphids have no reason to migrate, most adults will be wingless.

However, when plants become unsuitable habitats, or when overcrowding occurs, winged aphids develop and migrate to other plants or crops.

Winged aphids may originate in weeds or neglected garden plants in the neighbourhood. They are less likely to come from strong, healthy plants. Even when disturbed, aphids move quite slowly.

There are many aphid species and they attack just about every type of plant. They also come in many colours. All aphids feed by sucking on plant juices and they may transmit plant diseases at the same time. The leaf distortions so often seen with aphids are mostly caused by transmitted viruses. Aphids are most active in spring and autumn.

Control

Aphid infestations, which originate from nearby, can be prevented by removal of host weeds and neglected, stressed plants, and by keeping target plants well watered, fertilised and healthy.

Citrus aphids and predatory ladybug

Encouraging beneficial organisms which attack aphids, such as ladybirds, hoverflies, parasitic wasps and lacewings, will help to keep aphids to a minimum. Beneficial organisms can be supported/encouraged by using minimal amounts of broad spectrum pesticides.

Aphids can be removed from plants with a jet of water, squashed with finger and thumb or sprayed with organic garlic and chilli sprays.

Sprays with horticultural soap will desicate and suffocate the insects and horticultural oil will smother the insects but these organic products should not be used when the weather is above 32°C as plant leaves can burn. Alternative products are the low toxicity, residual chemicals imidacloprid and acetamiprid.

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