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Aphids in general

The woolly beech aphid(Phyllaphis fagi)

Phyllaphis  fagi

 White woolly spots placed under the leaf underside of beech (Fagus silvatica) are a certain symptom of the woolly beech aphid. ! (Phyllaphis fagi)
Photo: Magnus Gammelgaard


Beech hedges have become very popular everywhere in Denmark. Not odd, because the beech tree has many splendid growing advances. When the plants are cut, you achieve a thick hedge, which keep its brown leaves for the whole winter season.

Also the beech hedges do not have the same cutting demands. You do not have to cut the hedges twice like by the privet hedges.
Beech can be a little difficult to establish, because it demands that the soil is well drained. The roots do not like if the soil has been compressed by heavy machinery. This is often to be found in addition to new construction work.

Phyllaphis  fagi

At heavy attack on new leaves and shoots, the growth can bee stopped (Phyllaphis fagi).
Photo: Magnus Gammelgaard




Biology

The woolly beech aphids are over wintering as eggs in addition to buds or bark. The eggs hatches close to the time of bursting into leaves. The first individuals are very describing called ancestress.
The mothers are giving birth to young ones, which are forming colonies at the bag site of the leaves.
A part of those new individuals are borne with wings, which make them able to migrate to other plants.

Also those aphids with wings (2. generation) are giving birth to new aphids, but only individuals with wings.
The next generation are without any wings. When the autumn is getting close, both male and female are to be born. The mating can take place and the eggs are laid, the life circles are bee completed.



Symptoms

The aphids are covered entirely by white waxy filaments, that are secreted from its body.
The woolly beach aphid secretes a lot of sugar, which make the leaves shiny and sticky. The sugary substance called honeydew allows the growth of a black sooty mould.
Often the ants are attracted to this sugar and the present of ants shows, that that aphids are to be found not fare away.

The attack from beech woolly aphids varies from one year to another depending of the actual climate the specific year.

Heavy infestations can result in leaves at the shoot tips becoming distorted and sometimes turning brown and drying up. Normally the damages are not that devastating and will only be a problem in newly planted beeches, where the growth will be inhibited.
From time to another the populations can rise and dead shoots can be found.
So it is the sticky leaf from the sugary substance and the growth of a black sooty mould that is the real problem especially when you are cutting the hedges.



Phyllaphis fagi

Woolly beech aphid, heavy attack).
Foto: Magnus Gammelgaard




Phyllaphis fagi

Imago with wings. Ready to fly to another plant).
Foto: Magnus Gammelgaard


Precautions

Luckily a lot of natural enemies are to be found. Predators and parasitoids, which are capable to regulate the population. Ladybugs, parasitoids and especially syrphid flies eat a lot of beech aphids.

However they have been a great problem in nurseries in the last years. A lot of investigations have been carried out because many would like production of beeches without any use of pesticides. A large investigation is done at the Danish Forest and Nature Agency and can bee seen at: :http://www.sns.dk/planteavl/planter/bladlus.htm

I private gardens where you don't want to use any kind of chemical pesticides, the recommendations has been to us wash down with cold water.

Chemical control:


Aktiv stof Handelsnavn Mere information
Thiacloprid
kaliumoleat
Calypso
Flere Insektsæber
bayergarden.dk
insektsaebe.htm






The use of chemical sprays normally is harmful for the natural biological balance in the garden.

If you want to read more about aphids in general, you can visit the: bladluseng.htm

Alternative control: Look up :Botanical pesticides

Growers also use:
  • Pirimor (pirimicarb)
  • Buldock 025 SC (Beta-cyfluthrin 25 g/l)
  • Fastac 50 (Alpha-cypermethrin).
  • Cyperb 100 (cypermethrin)
  • Karate 2,5 WG (Lambda-cyhalothrin)
  • Perfektion (dimethoat)
  • Movento (Spirotetramat 100 g/l )

  • se evt: Middeldatabasen


If you have any information's ore good advices, I should be very glad to receive those and I would try to bring them on this website.

Opdateret d. 2.2.2012
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