The, more or less dish-shaped, widened top part of the flower stalk of Asteraceae (Compositae) where the florets are inserted in the flower head.

The first larval stage of scale insects and whiteflies. Later stages are immobile and attached to the plant, therefore this first, mobile, stage is crucial for the dispersal of the species.

literally: opponent; an organism that in some way has a negative influence, e.g. a competitor or predator.

sclerite (hardened chitine plate) at the dorsal side of a thoracic or abdominal segment in an insect.

sclerite (hardened chitine plate) at the ventral side of a thoracic or abdominal segment in an insect.

A specialised form of setae (“hairs”) in some insects. They consist of a cup-shaped base, with on top a short dagger- or tube-shaped seta. In Triozidae larvae the margins of the abdomen, wing pads and head bear a row of sectasetae, each one of which produces a long, glistening thread of wax

A number of setasetsae as they are standing along the margin of the wingpads of Trioza remota (from Rapisarda, 1994a).

Trioza remota larva; the sectasetae are too small to be seen, but the wax threads they have produced are conspicuous.

Less often used equivalent of siphunculus

A sac, made out of wax threads or silk, containing eggs.

(pl oviparae).Aphids generally during the summer pass through a number of consecutive generations of viviparae, females that asexually produce living young. The final generation that is born in autumn is different, consisting of males and females that, after being fertilized, lay eggs that enable the population to hibernate. These egg-laying females are called oviparae.

With more or less strongly reduced wings.

(pl viviparae). Female aphid that, without fertilisation, produces living young. Often viviparae are wingless (“apterae”), but they may winged as well (“alatae”). Usually a species during summer has a number of generations of viviparae. In autumn male and female aphids are born. The fertilised females (the “oviparae”) lay eggs by which the population passes the winter.

An alate vivipara

Summer dormancy; a period when an insect enters a state of immobility and lowered metabolism, analogous to hibernation.

A mass of conidia, extruded as a white thread

Eudarluca caricis, a parasite in the telia of a rust fungus

In aphids the lower lip (labium), that ahs been transformed into a hollow tube. Through this tube the stylets can be pushed out. The stylets, strongly modified mandibles and maxillae, pierce into deeper layers of the plant’s tissue and bring up the sap.

In sawflies it sometimes happens that the oviposition scar functions as a gall for the very youngest stage of the larva; once the scar has been eaten out the larva starts living free on the plant. The scar then is addressed sometimes as a protocecidium, “predecessor of a gall”.

protocecidium of an unknown sawfly on Alchemilla; upperside

underside; the protocecidium was already vacated

The body segments of sawfly larvae are subdivided by deep grooves. The number of these subdivisions, “annulets”, is of taxonomic importance.

(From Lorenz & Kraus, 1957)

A pair of short appendages at the terminal segment of some sawfly larva.

Slab of chitin

Larvae of insects with an incomplete metamorphosis, in particular Hemiptera (bugs, aphids and relatives) are often addressed as nymphs.

A female aphid in, or coming out of a gall.

The opposite of holocyclic; see there

The life cycle of some insect groups, like aphids and gall wasps consists of an alternation between a sexual generation and an asexual one. Such a complete cycle is called holocyclic. Some, related species however may have an abbreviated cycle: either only a sexual stage, or continuous asexual reproduction; this situation is called anholocyclic.

An animal that lives in the nest, colony, or burrow and another animal species. In connection with this site generally a larva that lives in, and feeds on, a gall that has been caused by the actual galling insect. The severity of the ensuing competition varies strongly. Galls that are co-occupied by one or more inquilines often have an abnormal appearance.

Misshapen gall of Pontania proxima; the gall was disfugred because of the presence of several inquiline larvae tunnelling in the fleshy wall.

(Often just stigma). A cell in the venation of an insect wing, always at the frontal margin and not far from the tip, that mostly is thickened and darkly coloured.

The hair cover of a plant.

The “plume” on top of the fruit of most Asteraceae; Also to total of them within a flower head.

Flower head; the inflorescence of Asteraceae and some other families that is so compact that it looks (and functions) like a single flower.

A stalk supporting an inflorescence

Having a large number of generations per year; in warmer regions having one or more generations also during the winter. There is only a short period of pupal rest.

(pl teleutosori). Currently unusual equivalent of telium.

The large genus of rust fungi, Puccinia, is characterised by having two-celled teliospores. However, a, generally quite small, minority of the spores is unicellular; they are addressed as mesospores.

Needle-shaped.

Spindle-shaped.

Mostly brown plates at the ventral side (rarely also at the dorsal side) in some larvae of the genus Ectoedemia; they only occur in the youngest stages.

young larva of Ectoedemia atricollis in its mine.

(pl uredinia). The third stage in the life cycle of rust fungi, after the aecia and before the telia.The mostly look like light brown to chestnut brown powdery, up to 2 mm large pustules.

One generation per year.

The body part of an insect between head an abdomen, that in the larval stage (generally) bears feet, and in the imago (generally) also wings.

Less currently used synonym of teliospores.

Fungus of the class Ustilaginales.

Fungus of the class Pucciniales.

Generally: stalk; applied in particular for the stalk of a teliospore.

(pl telia). The fourth stage in the life cycle of rust fungi, Pucciniales. Generally they appear after the uredinia, and are darker in colour.

Puccinia ptarmicae: a telium under the microscope

Mature larvae of gall midges often have ventrally on the thorax a chitinous rod, at the front end ending in a small fork. The spatula is used by the larva when it has to force itself out of the gall.

Most of the spatula lies internal, just below the epidermis; only the part above the stippled line is external.

Living freely on the leaves; phrase used in particular for gall mites.

(pl sori). A compact cluster of spores forming fungal tissue, like an uredinium or telium.

Hairs of plants, and also their modifications in an erineum, are fundamentally different from the hairs of mammals. In the technical literature they therefore often are addressed as trichomes.

(pl setae). The “hairs” of arthropods differ in their structure fundamentally from those of mammals, and therefore are called setae. Thick and heavy setae also are designated as bristles.

Main axis of a composite leaf, or of fern leaf.

Cushon-shaped.

The sexual stage of a fungus (contrasting with anamorph).

(pl spermonia). First stage in the life cycle of the Pucciniales. It are mostly orange-coloured pycnidia the at maturity exude liquid.

Puccinia festucae on Lonicera periclymenum

Puccinia festucae

(pl sporodochia). Cushion-shaped organ, at the outer surface of which conidia are formed.

(pl siphunculi). A pair of rod-like appendages on the abdomen, an exclusive character of the family Aphididae, aphids. The exude a viscous liquid containing mainly excess sugars – to obtain the necessary amount of amino acids, aphids need to digest much liquid, and ingest much more sugars than needed. Shape, sculpture and even colour of the siphunculi are diagnostic. In some instances they are reduced to no more than flat pores.

The siphunculi of Pterocomma salicis are the most conspicuous

One-celled fungus, that reproduces asexually by sprouting or cell division. Some groups of fungi are permanently in this stage, but many Ustilaginomycotina, and also the species of Taphrina pass their anamorphic stage as yeasts.

(pl perithecia). Globular or flask-shaped organ, provided with an opening (ostium), containing asci.

Thick-walled cell, derived in a fertilised oogonium, embedded in the host plant tissue. Their biological function mostly is of a resting spore, in particular for hibernation.

Two still rather young oospores, each one in its oogonium.

(pl septa). Dividing wall, e.g. in a fungal spore or hypha. Often a septum contains a pore that enables some regulated connection between the protoplasma at either side. Hyphae without septa are called aseptate.

Most fungal infection are local. However, in some species the mycelium pervades the entire plant body. This has important biological implications: the fungus may be dispersed by infected seed, and the fungus may hibernate in the below-grond pats of the plant.

A thick-walled fungal spore that develops from a hyphe cell.

A prolongation of the terminal abdominal segment in aphids. Its shape is diagnostic.

-> caespitulus

(pl caespituli). Cluster of hyphae, conidiophores and conidia free on a leaf, often erupting through a stoma. It forms the anamorphic stage of a variety of fungi, grouped conventionally under the term Hyphomycetes. Instead of the technical term often the word “colony” is used.

(pl sclerotia). A hard, dry of fungal tissue that is resistant to unfavourable conditions and may remain in a resting state for an extended period.

(pl sporangia). A hollow organ, in which spores are formed.

A stalk, branched or not, bearing sporangia.

(pl stromata). A compact mass of fungal tissue; generally reproductive organs are formed inside.

Pin-sized puncture made by an agromyzid female with her ovipositor in the surface of leaf. She subsequently drinks from the extruding sap. Males, not having an ovipositor, drink from the punctures that the females have made.
A single female can make many tens of punctures in a leaf. When Agromyzidae are a pest it often is not because the mines made by the larva, but because of water loss of the leaves caused by the feeding punctures. Next to Agromyzidae also Scaptomyza (Drosophilidae) species use their ovipositor to make feeding punctures.

Phytomyza podagrariae: feeding punctures

(pl stemmata). The individual facets of the eye of an insect larva. They are not lying adjacent to another, like in the imaginal eye.

(pl pycnidia). Cavity in the plant tissue, in which asexual fungal spores (conidia) are formed, and ejected through a pore. Contrary to acervuli, pycnidia are situated deep in the plant tissue, and from the outside recognisable only by their opening.

Many aphid species go through an alternation of hostplants. In spring a fertilised female then starts a colony on a, generally woody, primary host plant. After spring, when the nutritional quality of the host plant’s juices is diminishing, migration takes place to a secondary, non-woody, host plant.

Blotch that originates when a gallery is so densely wound that the separating walls wholly or partly disappear (are eaten away). Sometimes the remnants of the walls are visible as secondary feeding lines; more often the frass pattern indicates a secondary blotch.

Blotch, caused by the larva feeding from the centre in all directions.

Cell or small blotch, often separated from the main mine, where pupation takes place. More or less distinct part of the mine, in which the pupa(rium) is waiting.

Arrangement of remnants of green leaf tissue in a pattern of parallel lines of made by the mowing movement of an agromyzid larva that is grazing away the leaf tissue while lying on its side.

Trypeta artemisiae: primary feeding lines