GALL MITES
 
When I saw plant galls for the first time I wanted to know what species there were to be found basically, and so I started collecting anything that looked like a plant gall. Boxes full of them I have now. Nowadays I think it is better for me to take pictures (digital or slides) and when you are interested in the gall maker itself, it is a good idea to try to get the inhabitants to emerge from the galls. The list of species described below are gall makers and their hosts, from species that I myself or another gall studying person has seen. A description is given and, where possible, a picture. For people who are interested in the Dutch distribution of pant galls can soon take a look at the database we are preparing for this website. Since the subject of plant galls becomes more popular only recently, we do not have yet such an extended database. Any contribution is welcome!
 
Aceria drabae is a mite that is most probably mainly occurring in the coastal area of the Netherlands, on Cardamine hirsuta. In the Summer and late Summer the plants can be found stunted with hardly any rozette formed, with a lilac-purple stem and distorted, rather swollen very hairy leaves. Hardly or no flowers. Seen at Schiermonikoog and Texel.  

   

Aceria erinea On Juglans regia you can usually find Aceria erinea. These mites cause a bulge to form between veins of the upper side of the leaf and a depression on the underside. The bulges are very obvious, also because the plant cells have become extra large. The depression is covered with erineum, many little hairs, first white, pale brown later.

  


(Foto's: B. Kabbes)

    

   
Aceria genistae occurs on native broom, Cytisus scoparius. This mite causes globeshaped, witches' broom-like disformation. The buds form into a distorted mass of miniture leaves, irregular and about 5 till nearly 30 mm across. The leaves are covered with grey-brown hairs and the edges are curled upwards. Native broom does not occur everywhere and the gall may not show on every location broom is present. Jeanine Wolfs (see pictures) found the species January 2005 at Haaren, east of Tilburg. In February I noticed gall on four bushes in park Insel Hombroich, Neuss Holzheim, Germany. If anyone sees this species in some other place in the Netherlands (or elsewhere), please let us know!


Pictures: Jeanine Wolfs
   
Aceria laticincta causes spectacular purple deformations on Lysimachia vulgaris. The flowers develop to odd shapes with hairs, and never look like flowers, but more like leaves of some sort. I found a specimen at the Meinweg in Limburg in 2001 and I don't know how common it is. The picture shows a specimen from Gozée, Belgium.
Picture: J. Y. Baugnée
 
Aceria macrochelus is a common species of gall mite occuring on hedge maple (Acer campestre). In the angle between veins of the leaf protrude globeshaped, to 2 mm high, smooth or scarcely haired, brown to red coloured galls on top of the leaf. Underneath is the gall opening situated. The inner surface and the opening are covered with multi-celled hairs (DvL). There are usually only 8 to 10 galls on a leaf, or more or less.


(Picture: R.J. Koops)
 
 Aceria macrotrichus is a small red gall mite that lives in great numbers in the thickened folded veins of the leaf of Carpinus betulus (hornbeam). This growth causes wavy ridges, with the slit-like opening on the upperside of the leaf. There are often several wavy ridges present on a leaf. When trongly affected the leaf coils upwards. According to DvL the gall has been spotted several times in Zuid-Limburg, the Netherlands. The picture on the right was made on National Park Hoge Veluwe, October 2004.

   
Aceria megacera is a mite that causes the flower heads of Mentha aquatica (water mint) to deform into a big bobbley lump. Its colour is pink and green and it is a bit hairy all over.
   
Aceria nervisequus - Not many mite-species occur on Fagus sylvatica (Beech). Aceria nervisequus makes the veins of the leaves of Beech show a pattern of long, white hairs. According to Docters van Leeuwen the gall has not been found since Nijmegen a 100 years ago! I found my specimen in Glimmen just south of Groningen, and also at Bingerden, near Angerlo. So perhaps it is not so rare as suggested.

  
Aceria nervisequa ssp. maculifera I found underneath the leaves of a Red Beech (Fagus sylvatica) at a burial site in Westeremden. Whole patches were covered with a pink colored carpet of hairs and it made the whole leaf glow pink.  
 
Aceria (Phytoptus) origani causes inflorescence and thickening of the tops of not-flowering stalks of wild marjoram, Origanum vulgare. The galls are matted with white hairs. I found my specimens in great numbers on the steep slopes along the rail track of the "miljoenenlijntje" in Zuid Limburg in the far south of the Netherlands.
   
Aceria pseudoplatani can be found on Acer pseudoplatanus and on A. platanoides. In cases of good coverage the leaves can wrinkle up a little. The patches of erinea bulge out because of the tops of the erinea being thickened a little. The erinea color from white to brownish.  
 
Acalitus rudis is is a mite that can often be found on Betula pendula (silver birch) and B. pubescens (downy birch). In the beginning the patches are white, but later they turn pink and brown. I have seen them on the upper side of the leaf, but usually they occur on the underside.  
 
Aceria tenellus is a gall mite that induces a smooth shiny bulge on the upperside of the leaf in the angle between the main veins of Carpinus betulus (hornbeam). The hairy opening is on the underside of the leaf.

underside
 
Eriophyes leiosoma causes the growth of hairy patches on the bottom side of the leaves of Tilia species (Lime tree), but also hairy deformations on the sepals and other flowering parts. The edges of the sepals curl to both sides along the length direction, first covered with white and later with brown erinea (hairs). The mites have a brown-pinkish appearance and can be admired in great numbers when the erinea have turned brown.

 
Eriophyes prunispinosae is common on blackthorn (Prunus spinosa) and usually causes deformations on the leaf edge, but sometimes also on the leaf blade. they are pouch-like pustules that can be roud od elongated. The galls are usually light-pink and hairy and have an opening on the upper surface of the leaf.


(Picture: G.J. Pranger)
 
Colomerus (Eriophyes) vitis is every now and than noticed by people owning a grape vine (Vitis vinifera), like Mrs Ria Lemmers from Delft. On the underside of the leaf are patches of erinea visable and on the upper side of the leaf is a slight elevation of the leaf visable at every patch. The erinea (hairs) have a white colour at early summer and colour red and brown-red during late summer. According to Doctors van Leeuwen the erinea are single cellular, bending and without any branches. Usually there are several to many patches present on one leaf. Sometimes there is no elevation visible on the upper part of the leaf.

(Pictures: R. Lemmers)
 
Phyllocoptes (Eriophyes) goniothorax is a gall mite on hawthorn (Crataegus monogyna) that rols the edges of the leaves. The rolled edges become slightly thickened and colour yellow and red when older. The mite also occurs on the underside of the leaf. Hairy patches appear that are purple-red to white in colour.
   
Phytoptus padi is a mite that causes rather large pillars on the upper part of the leaves of Prunus padus. The shape varies, but the colour usually becomes somewhat pink or red. The leaves can be so densely covered with galls that the leave gets deformed and wrinkled. 

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