{"id":697775,"date":"2019-12-09T07:35:34","date_gmt":"2019-12-09T05:35:34","guid":{"rendered":"https:\/\/bladmineerders.nl\/backgrounds\/specials\/gallers-on-crataegus\/"},"modified":"2023-11-17T17:08:11","modified_gmt":"2023-11-17T16:08:11","slug":"gallers-on-crataegus","status":"publish","type":"page","link":"https:\/\/bladmineerders.nl\/en\/host-plants\/plantae\/spermatopsida\/angiosperma\/eudicots\/superrosids\/rosids\/fabids\/rosales\/rosaceae\/amygdaloideae\/maleae\/crataegus\/gallers-on-crataegus\/","title":{"rendered":"gallers on genus Crataegus"},"content":{"rendered":"

Dichotomous table for gallers on Crataegus<\/em><\/h2>\n

by Hans Roskam<\/p>\n

\n

1a<\/strong> On flowers => 23<\/p>\n

1b<\/strong> On vegetative plant parts => 2<\/p>\n<\/div>\n

<\/p>\n

\n

2a<\/strong> On buds, leaves and thinner twigs => 4<\/p>\n

2b<\/strong> In root, trunk or on thicker branches => 3<\/p>\n<\/div>\n

<\/p>\n

\n

3a<\/strong> Irregular lumpy swelling on root, 10 mm across or much larger; soft at first, later woody; contains red, purple or brown woolly aphids covered with copious white wax; gall persists long after aphids have left; rare. Crataegus spp.: Eriosoma lanigerum<\/a><\/em><\/p>\n

3b<\/strong> Branches or stems often with conspicuous, club- or barrel-shaped swellings. Crataegus spp.: Viscum album<\/a><\/em><\/p>\n<\/div>\n

<\/p>\n

\n

4a<\/strong> Malformations of various shape, soon occupied by fructifications of fungi => 20<\/p>\n

4b<\/strong> Malformations caused by animals => 5<\/p>\n<\/div>\n

<\/p>\n

\n

5a<\/strong> Aphid galls => 15<\/p>\n

5b<\/strong> Other causers => 6<\/p>\n<\/div>\n

<\/p>\n

\n

6a<\/strong> On younger stems, shoot tips or leaves => 7<\/p>\n

6b<\/strong> Buds slightly swollen, not opening, occasionally abnormally pubescent. C. laevigata, monogyna: Eriophyes calycobius<\/a><\/em><\/p>\n

6c<\/strong> Vegetative bud unopened, transformed into a rotund mass of small, strongly folded leaves, about 5 mm wide, the external ones making a sort of hood enveloping a shell of aggregated dying leaves. Crataegus spp.: Anthonomus bituberculatus<\/a><\/em><\/p>\n<\/div>\n

<\/p>\n

\n

7a<\/strong> Malformations on single, or several terminal leaves, loosely arranged => 9<\/p>\n

7b<\/strong> Galls on thin stems or on shoot tips => 8<\/p>\n<\/div>\n

<\/p>\n

\n

8a<\/strong> Leaves on distinctly stunted, slightly thickened shoot tip often in many densely tuft-like clusters. Leaf blades sessile, \u00b1 stunted, rugose, occupied by many bolt-shaped or globular green or reddish proliferations. Between the inner, very small leaves are many white, later orange larvae. C. azarolus, coccinea, laevigata, monogyna, rhipidophylla: Dasineura crataegi<\/a><\/em><\/p>\n

=<\/strong> Associated are the yellowish larvae of the inquiline gall midge Prolauthia circumdata<\/a><\/em>.<\/p>\n

8b<\/strong> Shoot axis with brown-green swelling, sometimes extending onto the petiole, with easily loosening epidermis. C. laevigata, monogyna<\/em>: Unidentified gall midge<\/p>\n

=<\/strong> The “Hawthorn twig gall midge” Resseliella crataegi<\/a><\/em>, with larvae living gregariously under bark, has not been observed to cause galls.<\/p>\n

8c<\/strong> Bark of younger twigs usually with several, \u00b1 distinctly rimmed depressions, which contain a rotund, whitish- to brownish-grey scale insect, the inducer. C. rhipidophylla: Epidiaspis leperii<\/a><\/em><\/p>\n<\/div>\n

<\/p>\n

\n

9a<\/strong> Leaves curled or with many small swellings or pocks => 12<\/p>\n

9b<\/strong> Leaf margin rolled or leaf blade abnormally pubescent => 10<\/p>\n<\/div>\n

<\/p>\n

\n

10a<\/strong> Rolls of leaf margins => 11<\/p>\n

10b<\/strong> Underside of leaf with white or violet-red erinea of slightly club-shaped hairs. C. coccinoides, laevigata, macrocarpa, monogyna, nigra, rhipidophylla, sanguinea: Phyllocoptes goniothorax<\/a><\/em><\/p>\n

10c<\/strong> Upper side of leaf slightly protruding at junction of midrib and side vein; corresponding area on underside weakly pubescent. Crataegus spp.: Eriophyes albaespinae<\/a><\/em><\/p>\n

10d<\/strong> Underside of leaf with a longitudinal groove, abnormal pubescence absent. C. laevigata, rhipidophylla: Aculops crataegumplicans<\/a><\/em><\/p>\n<\/div>\n

<\/p>\n

\n

11a<\/strong> Leaf margin tightly rolled downwards, with short club-shaped, at first white, then brownish hairs sometimes extending as erinea into the leaf blade or developing there as isolated patches. C. coccinoides, laevigata, macrocarpa, monogyna, nigra, rhipidophylla, sanguinea: Phyllocoptes goniothorax<\/a><\/em><\/p>\n

11b<\/strong> Leaf roll, containing several red larvae. C. monogyna, laevigata<\/em>: Unidentified gall midge<\/p>\n<\/div>\n

<\/p>\n

\n

12a<\/strong> Leaf blade with many pocks or small swellings => 13<\/p>\n

12b<\/strong> Several leaves of suckers on curved stems bent together into a loose aggregation. Leaf blades \u00b1 crumpled. Containing a froth-covered nymph. Crataegus spp.: Philaenus spumarius<\/a><\/em><\/p>\n<\/div>\n

<\/p>\n

\n

13a<\/strong> Leaf blade with one-sided archings => 14<\/p>\n

13b<\/strong> Leaf blade with many pocks protruding on both sides, often pale green; with narrow opening on underside, occasionally also on upperside. C. laevigata, monogyna: Eriophyes crataegi<\/a><\/em><\/p>\n<\/div>\n

<\/p>\n

\n

14a<\/strong> Leaf blade with many small bulging swellings, yellowish or often carmine-red. Froth-covered nymphs in grooves on underside. C. laevigata, monogyna, rhipidophylla: Cacopsylla melanoneura<\/a><\/em><\/p>\n

14b<\/strong> Leaf blade browned by vagrant gall mites. C. macrocarpa, monogyna, rhipidophylla: Calepitrimerus armatus<\/a><\/em><\/p>\n

14c<\/strong> In similar malformations on hawthorns during the same period also lives Cacopsylla peregrina<\/a><\/em><\/p>\n

14d<\/strong> Leaf blade with small depressions on the underside, and corresponding tiny bulges, often coloured red, on the upper side. In each cavity is one flat froth-covered nymph. C. laevigata, monogyna: Cacopsylla affinis<\/a><\/em><\/p>\n

=<\/strong> The psyllid Cacopsylla crataegi<\/a><\/em> is only weakly cecidogenic, and often reported only as inquiline, or successorium (secondary inhabitant) in aphid galls.<\/p>\n

14e<\/strong> Leaf blades usually bent downwards along the venation. Malformations without abnormal pubescence. C. laevigata, rhipidophylla: Aculops crataegumplicans<\/a><\/em><\/p>\n<\/div>\n

<\/p>\n

\n

15a<\/strong> Leaves variously curled, leaf blades not discoloured or sometimes marbled yellow. Malformation usually with many leaves, loosely arranged on shoots or \u00b1 clustered on shoot tips => 17<\/p>\n

15b<\/strong> Leaves swollen, bladder-like, and conspicuously discoloured yellowish or reddish. Galls caused by several Dysaphis<\/em> species, all host alternating and difficult to separate => 16<\/p>\n<\/div>\n

<\/p>\n

\n

16a<\/strong> Leaf blade usually keel-shaped, curved downwards; segments between the veins especially close to the midrib strongly inflated, bladder-like, discoloured yellowish, not red. Galls mainly on several leaves distributed over the plants. C. laevigata, monogyna: Dysaphis ranunculi<\/a><\/em><\/p>\n

16b<\/strong> Galls usually strongly reddened, otherwise not different from previous species. Often on several neighbouring leaves occurring already during unfolding of leaves. Larvae usually greenish or pink. Aphids mainly distinguished by their different host alternation. Aphids interbreed on Crataegus<\/em>. Exules on roots, at stem base or sheaths, rarely on leaf blades of basal leaves of various Apiaceae:<\/p>\n

a<\/strong> Migrating to Daucus carota, sativus (Anthriscus, Aegopodium): Dysaphis crataegi<\/a><\/em> <\/p>\n

b<\/strong> Migrating to Aethusa cynapium: Dysaphis crataegi subsp. aethusae<\/a><\/em><\/p>\n

c<\/strong> Migrating to Angelica: Dysaphis angelicae<\/a><\/em><\/p>\n

d<\/strong> Migrating to Apium graveolens<\/em> and Petroselinum crispum: Dysaphis apiifolia subsp. petroselini<\/a><\/em><\/p>\n

e<\/strong> Migrating to Heracleum, Conium: Dysaphis lauberti<\/a><\/em><\/p>\n

f<\/strong> Migrating to Laserpitium, Anthriscus: Dysaphis laserpitii<\/a><\/em><\/p>\n

g<\/strong> Migrating to Petroselinum, (Levisticum officinale, Conium): Dysaphis apiifolia subsp. petroselini<\/a><\/em><\/p>\n

h<\/strong> Migrating to Pastinaca sativa: Dysaphis crataegi subsp. kunzei<\/a><\/em><\/p>\n<\/div>\n

<\/p>\n

\n

17a<\/strong> Leaves not conspicuously discoloured => 18<\/p>\n

17b<\/strong> Several leaves at shoot tip loosely arched, marbled yellow, soon drying. C. laevigata, monogyna, rhipidophylla, sanguinea: Prociphilus pini<\/a><\/em><\/p>\n

17c<\/strong> Cherry-red to crimson curled-leaf galls in spring. Crataegus laevigata, monogyna: Dysaphis apiifolia<\/a><\/em><\/p>\n

17d<\/strong> Red curled-leaf galls on leaves. C. curvisepala: Dysaphis incognita<\/a><\/em><\/p>\n

17e<\/strong> Pale green or red curled-leaf galls. C. orientalis: Dysaphis virgata<\/a><\/em><\/p>\n<\/div>\n

<\/p>\n

\n

18a<\/strong> Aphids green => 19<\/p>\n

18b<\/strong> Aphids black; rolling and curling of young leaves. Crataegus spp.: Aphis fabae<\/a><\/em><\/p>\n<\/div>\n

<\/p>\n

\n

19a<\/strong> Leaves on the unshortened shoots normally distributed or sometimes loosely clustered at shoot tip. Midrib conspicuously bent, screw-like, leaf blade sometimes undulate, nested, loosely or more compactly bent downwards. Aphid with short, thick green siphunculi. C. coccinea, laevigata, monogyna: Rhopalosiphum oxyacanthae<\/a><\/em><\/p>\n

19b<\/strong> Leaves at stunted ends of shoots bent downwards over tip and margins rolled. Aphid with rather long black siphunculi. Crataegus spp.: Aphis pomi<\/a><\/em><\/p>\n<\/div>\n

<\/p>\n

\n

20a<\/strong> Leaves curled or swollen, bladder-like, also young stems partially \u00b1 thickened and curved, occupied by grey-white fungal fructifications => 22<\/p>\n

20b<\/strong> Considerable yellowish, also reddened, pad- or bulge-shaped swellings on leaves, young stems and even fruits. Galls occupied by spermogonia and aecia => 21<\/p>\n<\/div>\n

<\/p>\n

\n

21a<\/strong> Peridium cylindrical, 2\u20133 mm long, lacerated brush-like later on, divided from the tip into many long lobes. Lateral walls of peridium cells with many, irregularly shaped tubercles of different size. Crataegus spp.: Gymnosporangium clavariiforme<\/a><\/em><\/p>\n

21b<\/strong> Aecia similar. Lateral walls of peridium cells with strong transversely and obliquely running tubercles and ridges. Crataegus spp.: Gymnosporangium confusum<\/a><\/em><\/p>\n<\/div>\n

<\/p>\n

\n

22a<\/strong> Leaves with yellowish-green or reddened bladder-like swellings, at maturity appearing white-frosted because of presence of many asci. Sori occasionally slightly arched, usually on one side, and \u00b1 curved swellings on young shoots, flower peduncles and even floral parts; sporadically developing almost witches\u2019 broom-like malformations. C. laevigata, monogyna, nigra, sanguinea: Taphrina crataegi<\/a><\/em><\/p>\n

22b<\/strong> During development of infected young shoots, according to response ability, the internodes partially appearing shortened, slightly thickened, partially etiolated, elongated and in case of mainly one-sided infestation \u00b1 conspicuously curved and often \u00b1 reddened. Diseased organs covered with a loose white mycelium. Crataegus spp.: Podosphaera clandestina<\/a><\/em><\/p>\n<\/div>\n

<\/p>\n

\n

23a<\/strong> Malformations caused by fungi on flower parts or young fruits => 21, 22<\/p>\n

23b<\/strong> Malformations caused by animals => 24<\/p>\n<\/div>\n

<\/p>\n

\n

24a<\/strong> Outer parts of flower buds, especially basally, slightly swollen, not opening. Between the inner parts occur larvae with inconspicuous head capsules => 25<\/p>\n

24b<\/strong> Receptacle and ovaries sometimes facultatively slightly swollen. Flowers remain closed, corolla distinct between healthy flowers because of its premature browning. Inside is a single larva with distinct head capsule. C. laevigata, monogyna: Anthonomus pedicularius<\/a><\/em><\/p>\n<\/div>\n

<\/p>\n

\n

25a<\/strong> Larvae ivory-coloured, jumping. C. laevigata, monogyna: Contarinia anthobia<\/a><\/em><\/p>\n

25b<\/strong> Larvae red, non-jumping. C. crus-galli, laevigata, monogyna: Dasineura oxyacanthae<\/a><\/em><\/p>\n

=<\/strong> Inquiline of Dasineura oxyacanthae<\/em>, larvae orange-coloured, non-jumping: Dasineura fusca<\/a><\/em><\/p>\n<\/div>\n

<\/p>\n","protected":false},"excerpt":{"rendered":"

Dichotomous table for gallers on Crataegus by Hans Roskam 1a On flowers => 23 1b On vegetative plant parts => 2 2a On buds, leaves and thinner twigs => 4 2b In root, trunk or on thicker branches => 3 3a Irregular lumpy swelling on root, 10 mm across or much larger; soft at first, […]<\/p>\n","protected":false},"author":3,"featured_media":0,"parent":32244,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"categories":[47],"tags":[],"class_list":["post-697775","page","type-page","status-publish","hentry","category-host-plant-genus-galler"],"_links":{"self":[{"href":"https:\/\/bladmineerders.nl\/en\/wp-json\/wp\/v2\/pages\/697775","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/bladmineerders.nl\/en\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/bladmineerders.nl\/en\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/bladmineerders.nl\/en\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/bladmineerders.nl\/en\/wp-json\/wp\/v2\/comments?post=697775"}],"version-history":[{"count":0,"href":"https:\/\/bladmineerders.nl\/en\/wp-json\/wp\/v2\/pages\/697775\/revisions"}],"up":[{"embeddable":true,"href":"https:\/\/bladmineerders.nl\/en\/wp-json\/wp\/v2\/pages\/32244"}],"wp:attachment":[{"href":"https:\/\/bladmineerders.nl\/en\/wp-json\/wp\/v2\/media?parent=697775"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/bladmineerders.nl\/en\/wp-json\/wp\/v2\/categories?post=697775"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/bladmineerders.nl\/en\/wp-json\/wp\/v2\/tags?post=697775"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}