| Elm leaf beetle | |
|---|---|
 | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| Order: | Coleoptera |
| Infraorder: | Cucujiformia |
| Family: | Chrysomelidae |
| Genus: | Xanthogaleruca |
| Species: | X. luteola |
| Binomial name | |
| Xanthogaleruca luteola (Müller, 1766) | |
| Synonyms | |
Xanthogaleruca luteola, commonly known as the elm-leaf beetle, is a beetle species in the family Chrysomelidae that is native to Europe but invasive in other parts of the world. [2] [3]
The imago (adult beetle) is 6–8 mm in length, and ranges from yellow to green in colour, with a spot on its head, an hourglass mark and two spots on the pronotum, and a broad, dark stripe along the edge of each elytron. The larvae are usually black, occasionally black and yellow, with multiple rows of dots on the back and on the sides and < 13 mm long. The pupae are orange-yellow with black chaetae. The ova are yellow, and laid in spindle-like clusters of < 25 on the undersides of the elm leaves.
These beetles are common in the Western Palearctic realm from Portugal to Central Asia. Indigenous to Europe, they were accidentally introduced to North America and Australia, and are now widespread, and are serious pests in Australia [2] and parts of North America. [3]
X. luteola is a serious pest of the elm. Both the adults and larvae feed on the emergent leaves of the elm. Repeated heavy infestation rarely kills the tree outright, but weakens it, rendering it vulnerable to disease. Falling branches encourage elm bark beetles ( Scolytus multistriatus and S. schevyrewi ) to proliferate; the beetles are vectors of Dutch elm disease. [4]
Elm leaf beetles become active in the spring once temperatures rise above 52 °F (11 °C). In fact, weather is one of the most limiting factors in their population growth. A late spring freeze or long winter can kill off entire colonies. [4] The imagines depart their hibernation sites (often houses), the females laying their ova on the underside of the elm leaves. The ova hatch after one week, and the larvae immediately feed on the underside of the leaves. This larval stage lasts between two and three weeks, at the end of which larvae migrate to the lower part of the trees in search of bark crevices in which to pupate. The next generation emerges in midsummer after two to three weeks' pupation, and begins feeding on the leaves. The female can lay about 800 ova, but this ovipositing may be interrupted by shortening of the photoperiod to less than 14 hours, inducing a brief feeding bout before the search for a hibernation site. [5] [6]
Hosts are known to include English elm (U. minor 'Atinia'), wych (Scots) elm ( Ulmus glabra ), American elm ( Ulmus americana ), Siberian elm ( Ulmus pumila ), and Chinese elm ( Ulmus parvifolia ), as well as complex hybrids such as 'Homestead'. [5] The beetle has also been reported on Zelkova serrata . [6]
When X. luteola oviposits, U. minor releases plant volatiles which recruit the egg parasitoid Oomyzus gallerucae . U. minor is able to distinguish between oviduct secretions (small molecule proteinaceous compounds) and damage which occurs in the natural course of oviposition, releases different volatiles upon detection of the oviduct compounds. O. gallerucae is then able to distinguish between these different sets of volatiles and is only attracted to oviposition. Gravid X. luteola females also respond, but inversely: They are attracted to volatiles indicating undamaged and/or unoviposited Ulmus material. Gene expression studies have shown a large number of genes to be involved in the oviposition response process. [7] (See Tritrophic interactions in plant defense.)
Jasmonic acid is released during gravid females' herbivory on Ulmus spp. [7]
The first and most apparent symptoms are of skeletonization. During feeding, elm leaf beetle larvae skeletonize the leaves. They leave the outer edge and veins of the leaf intact, which gives the foliage a net-like appearance. Areas around the feeding site dry up and die, causing the leaf to drop prematurely. Adults, on the other hand, chew small, irregularly shaped holes in the expanding leaves. Trees that lose their leaves often develop a second set, only to have them consumed when the next generation is produced. [8]
In North America, there are few natural enemies, but in Europe, the larva of the beetle are often heavily predated by the chalcidoid wasp Oomyzus gallerucae . [9] [7] Insecticide sprays are of little use since by the time the infestation is apparent, the application will be too late to be effective. However, tree trunks banded with insecticides can limit repetition the following year by killing the larvae as they descend before hibernation. Soil injection [5] presents a non-invasive alternative to trunk injections with a 2-year effect on the X. luteola population.
Since overwintering elm leaf beetles infest the homes of those close to an elm leaf beetle infestation, it is suggested that all cracks outside the house should be sealed. It is discouraged to use insecticides unless there are really heavy colonies. [10]
Nearly all chemicals currently used commercially in Australia to treat Elm Leaf Beetle, regardless of brand name or delivery method, are neonicotinoid insecticides. This is the chemical type that has had (2016) a two-year ban placed on it by the European Commission, owing to the association between the widespread use of these chemicals and their impact on bee populations.[ citation needed ]
The Japanese beetle is a species of scarab beetle. The adult measures 15 mm (0.6 in) in length and 10 mm (0.4 in) in width, has iridescent copper-colored elytra, and a green thorax and head. It is not very destructive in Japan, but in North America and some regions of Europe, it is a noted pest to roughly 300 species of plants, including rose bushes, grapes, hops, canna, crape myrtles, birch trees, linden trees, and others.
The Asian long-horned beetle, also known as the starry sky, sky beetle, or ALB, is native to the Korean Peninsula, northern and southern China, and disputably in northern Japan. This species has now been accidentally introduced into the eastern United States, where it was first discovered in 1996, as well as Canada, and several countries in Europe, including Austria, France, Germany, Italy and UK.
Pieris rapae is a small- to medium-sized butterfly species of the whites-and-yellows family Pieridae. It is known in Europe as the small white, in North America as the cabbage white or cabbage butterfly, on several continents as the small cabbage white, and in New Zealand as the white butterfly. The butterfly is recognizable by its white color with small black dots on its wings, and it can be distinguished from P. brassicae by its larger size and the black band at the tip of its forewings.
Pieris brassicae, the large white, also called cabbage butterfly, cabbage white, cabbage moth (erroneously), or in India the large cabbage white, is a butterfly in the family Pieridae. It is a close relative of the small white, Pieris rapae.
The Mexican bean beetle is a species of lady beetle that can be an agricultural pest. It is one of the few North American lady beetles that feed on plants rather than other insects. It is found throughout Mexico and the eastern United States, and is abundant in the wetter and more heavily irrigated areas west of the Rocky Mountains. It does not tolerate extremely dry areas.
The American Elm cultivar Ulmus americana 'Exhibition' is a selection made by the Patmore Nurseries from seeds of a tree at Brandon, Manitoba. Released in 1952, 'Exhibition' was propagated by grafting.
The Chinese Elm cultivar Ulmus parvifolia 'Golden Rey' is an American clone patented by B. Rey in 1990.
The Chinese Elm cultivar Ulmus parvifolia 'Pathfinder' is another development by A. M. Townsend of the USDA National Arboretum registered in 1990.
Ulmus davidianavar.japonica 'JFS-Bieberich' is a Japanese Elm cultivar that was raised by the Sunshine Nursery, Oklahoma, from seed collected in China by proprietor Steve Bieberich. Emerald Sunshine proved only moderately successful in the US National Elm Trial, averaging a survival rate of 70% overall.
The American elm cultivar Ulmus americana 'Aurea' was cloned from a tree discovered by F. L. Temple in Vermont at the end of the 19th century.
The American Elm cultivar Ulmus americana 'Columnaris' was propagated by R. E. Horsey of the Rochester N.Y. Parks Department from a tree found by Mr John Dunbar at Conesus Lake, New York, in 1911, and originally described as a forma, Ulmus americana L. f. columnaris, f. nov.Rehder (1922). It was the earliest of a number of compact, columnar American elm cultivars, to be followed by 'Ascendens' and 'Augustine Ascendening'.
The American Elm cultivar Ulmus americana 'Kimley' was cloned c.1957 by the Sheridan Nurseries, Mississauga, Canada, from a large tree found near Oshawa, Ontario, Canada.
Macrodactylus subspinosus is a North American beetle of the family Scarabaeidae. The members of this genus are known as "Rose chafers", not to be confused with the European Rose chafer, Cetonia aurata. M. subspinosus occurs from Eastern Canada to Colorado and is considered a pest of many crops and flowers. It is given its common name of rose chafer because it eats the leaves of roses, although it also feeds on many other plants.
The American Elm cultivar Ulmus americana 'Flick's Spreader' was cloned from a tree discovered by John T. Flick on a farm near Hammon, Oklahoma. Cuttings were given to the Sunshine Nursery, Clinton, Oklahoma, in 1997, which later marketed the tree as 'Flick's Spreader'.
Cucumber beetle is a common name given to members of two genera of beetles, Diabrotica and Acalymma, both in the family Chrysomelidae. The adults can be found on cucurbits such as cucumbers and a variety of other plants. Many are notorious pests of agricultural crops. The larvae of several cucumber beetles are known as corn rootworms.
Bruchus rufimanus, commonly known as the broadbean weevil, broadbean beetle, or broadbean seed beetle is a leaf beetle which inhabits crops and fields, as well as some homes. It is a pest of faba beans. The adult beetles feed on pollen, while their larvae tunnel in seeds destroying crops and moving on to new ones once they dry out. The adult beetle, being one of the biggest of its genus, ranges from 3 to 5 mm in length.
Odontopus calceatus is a species of weevil which occurs in much of the eastern and southeastern United States. Its range is as far north as Massachusetts all the way south to the Gulf of Mexico, and from the Atlantic westward to the Mississippi River. Common names include yellow poplar weevil, sassafras mining weevil, tuliptree leafminer, tulip tree weevil, or the magnolia leaf miner.
Liriomyza trifolii, known generally as the American serpentine leafminer or celery leafminer, is a species of leaf miner fly in the family Agromyzidae.
Odoiporus longicollis, commonly known as banana stem weevil or banana pseudostem borer, is a species of weevil found in South Asia and South East Asia.
Oomyzus gallerucae is a species of chalcid wasp in the family Eulophidae. It is a parasitoid of the elm leaf beetle. The adults and larvae eat the eggs of the beetle.
