Leek moth | |
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Scientific classification | |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Insecta |
Order: | Lepidoptera |
Family: | Acrolepiidae |
Genus: | Acrolepiopsis |
Species: | A. assectella |
Binomial name | |
Acrolepiopsis assectella (Zeller, 1839) | |
Synonyms | |
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The leek moth or onion leaf miner (Acrolepiopsis assectella) is a species of moth of family Acrolepiidae (formerly Glyphipterigidae) and the genus Acrolepiopsis . The species is native to Europe and Siberia, but is also found in North America, where it is an invasive species. While it was initially recorded in Hawaii, this was actually a misidentification of Acrolepiopsis sapporensis . [1]
The leek moth is similar in appearance to other members of the genus Acrolepiopsis, with mottled brown and white wings. Its wing span is approximately 12 mm across. [1]
It is a pest of leek crops, as the larvae feed on several species of Allium by mining into the leaves or bulbs. [2] The shape of the leaf mine is variable, ranging from a corridor to a blotch, and can be with or without frass. This leaf mining can occur in the tubular leaves or in the stem. In the case of onions and shallots, the larvae mine into the bulb. In North America, where the moth is an invasive species and has few known natural predators, the species threatens the production and biodiversity of Allium, and it has the potential to destroy entire crops. [3] The parasitoid Diadromus pulchellus is used to control the spread of and damage caused by the leek moth in Europe and North America. [4]
The wings are brown mottled with white spots and measure about 12 mm across. High individual variation in wing pattern can make the leek moth difficult to distinguish from other Acrolepiopsis species at first, but its distinct genitalia make it easily identifiable. Males of this species can be identified by their long saccus, a portion of the male genitalia used for grasping females, and females by their long and flat ductus bursae, a portion of the female reproductive tract. [1] [5]
The leek moth is native to Europe, where it is present throughout the entire continent. Scandinavia and Russia mark the northwestern and northeastern bounds of its range, respectively, and its presence extends to Algeria in the south. [1] It is an invasive species in North America, where it was first discovered in Canada in 1993. [1] It has since expanded its North American range to include parts of Ontario, Quebec, Prince Edward Island, New York, [2] and Nova Scotia. [6] Climate models suggest that the leek moth's range could continue to expand to encompass a larger portion of eastern North America. [7]
The female leek moth selects the host plant for oviposition. She is drawn to the plant through thiosulphinates, chemical attractants released by the plant. Egg-laying does not take place immediately, however; it occurs only after longer contact with the leaf, during which time another chemical signal cues oviposition. Propyl-cysteine-sulfoxide has been shown to induce egg-laying in the leek moth and could be involved in host plant selection as a characteristic signal of Allium. [8]
Larvae feed on plants of the genus Allium, including:
The leek moth prefers A. sativum, garlic, A. porrum, leek, and A. cepa, onion, to other species of Allium. [4]
Oviposition takes place in three behavioral stages: slow walking, pausing, and egg-laying. [8] When given the choice between plants of the same species and of different sizes, females choose to lay their eggs on the larger plant. [9]
Development time from egg to adult is variable depending on temperature, generally ranging from 3 weeks at higher temperatures to 6 weeks at lower temperatures. Likewise, the number of generations possible each year depends on local climate conditions. Whereas three or more generations can typically be completed in Ontario, France, and Poland, only two can be completed in Sweden. [2]
Adults emerge in the spring and lay eggs within 10 days of adulthood. [2] Eggs are laid on the leaves of the larval host plant, into which first instar larvae mine and subsequently complete five instars, reaching a length of 13–14 mm when mature. Larvae are light yellow-green in color with a brownish-yellow head. After reaching maturity, fifth instar larvae emerge from the host plant and spin a cocoon, on the host plant or nearby. Cocoons are white in color, pupa reddish-brown. [1] If daylengths during previous larval stages are shorter than 15 hours, emergent adults will enter diapause to overwinter. Otherwise, adults lay another generation of eggs. [4]
Knowledge of the leek moth's natural predators in North America is limited, but several larval and pupal parasitoids of the species have been documented in Europe. Parasitoids lay their eggs within or attached to the body of the host, the parasitoid larvae ultimately killing the host. Parasitoids are shown to parasitize the leek moth to a greater extent when leek moth populations are large and in early leek moth generations, suggesting that parasitism is less significant in smaller populations and in later generations. The leek moth is most vulnerable to parasitism in its pupal stage when it is no longer protected by the interior of its host plant. [10]
Diadromus pulchellus , a host-specific parasitoid of the leek moth, has been introduced in the Ottawa region in Canada as a biological control method for the invasive moth. [4]
During mating, males respond to calling females with the emission of a pheromone containing n-alkanes. Males flutter their wings, which acts to volatilize the pheromone through heat generation and disturb the pheromone molecules. The pheromone acts as an aphrodisiac for the female while inhibiting the sexual behavior of other males. These compounds can be transferred to the female during mating and their sexual inhibitory effects on conspecific males favor the monogamy seen in the leek moth. [11]
In eastern Ontario, the leek moth undergoes three flight periods each year. The first flight period peaks in mid-May and consists of overwintering adults. The second peaks in early July and consists of first generation adults. The third peaks from late July to late August and consists of second generation adults. This pattern again suggests that three generations can be completed each summer in Ontario. [2]
Females rely on the olfactory detection of volatile chemoattractants in host plant selection. [8] Experiments suggest that the diets of female leek moths reared in laboratory conditions impact sensitivity to chemoattractants. When two strains of moths were raised in the laboratory, one fed leek leaves and the other fed an artificial diet supplemented with leek powder, the former strain showed greater sensitivity to volatile leek compounds. Furthermore, the strain fed leek leaves became progressively less sensitive to volatiles each generation. [12]
Adults enter diapause to overwinter when daylengths during their larval stage are less than 15 hours long. [4] This corresponds to the end of the breeding season and involves adults of the last generation of the summer. During diapause, mating and sex organ growth halt. [2]
The leek moth is an invasive species in North America. It was first discovered in North America in Ottawa, Canada in 1993, and was found in the United States 16 years later in Plattsburgh, New York in 2009. [3] It has since spread throughout much of eastern North America and its range is projected to expand further into the United States and Canada. [7] A pest of Allium crops, the leek moth poses threats both to Allium production and biodiversity. The larvae mine into the plant, reducing plant growth and causing physical damage. Organic farmers are especially vulnerable to the pest. [4] The leek moth has few known natural predators in North America, resulting in greater pest pressure than in Europe and causing severe damage to Allium plants, sometimes resulting in the loss of entire crops. [3] [4]
Several methods of leek moth pest control have been tested, including intercropping and trap cropping. [13] [14] Intercropping involves the growing of additional crops alongside the pest-susceptible crop to encourage oviposition on these additional crops. Intercropping has been found to be ineffective at controlling the spread of and damage caused by the leek moth. [13] When trap cropping is implemented, more eggs are laid on the trap crops than on the primary crop. [14] Research on leek moth pest control is ongoing.
The codling moth is a member of the Lepidopteran family Tortricidae. They are major pests to agricultural crops, mainly fruits such as apples and pears. Because the larvae are not able to feed on leaves, they are highly dependent on fruits as a food source and thus have a significant impact on crops. The caterpillars bore into fruit and stop it from growing, which leads to premature ripening. Various means of control, including chemical, biological, and preventive, have been implemented. This moth has a widespread distribution, being found on six continents. Adaptive behavior such as diapause and multiple generations per breeding season have allowed this moth to persist even during years of bad climatic conditions.
The Indianmeal moth, also spelled Indian meal moth and Indian-meal moth, is a pyraloid moth of the family Pyralidae. Alternative common names are weevil moth, pantry moth, flour moth or grain moth. The almond moth and the raisin moth are commonly confused with the Indian-meal moth due to similar food sources and appearance. The species was named for feeding on Indian meal or cornmeal, and does not occur natively in India. It is also not to be confused with the Mediterranean flour moth, another common pest of stored grains.
The light brown apple moth is a leafroller moth belonging to the lepidopteran family Tortricidae.
The African armyworm, also called okalombo, kommandowurm, or nutgrass armyworm, is a species of moth of the family Noctuidae. The larvae often exhibit marching behavior when traveling to feeding sites, leading to the common name "armyworm". The caterpillars exhibit density-dependent polyphenism where larvae raised in isolation are green, while those raised in groups are black. These phases are termed solitaria and gregaria, respectively. Gregaria caterpillars are considered very deleterious pests, capable of destroying entire crops in a matter of weeks. The larvae feed on all types of grasses, early stages of cereal crops, sugarcane, and occasionally on coconut. The solitaria caterpillars are less active and undergo much slower development. The species is commonly found in Africa, but can also be seen in Yemen, some Pacific islands, and parts of Australia. African armyworm outbreaks tend to be devastating for farmland and pasture in these areas, with the highest-density outbreaks occurring during the rainy season after periods of prolonged drought. During the long dry seasons ("off-season"), the population densities are very low and no outbreaks are seen.
Phthorimaea operculella, also known as the potato tuber moth or tobacco splitworm, is a moth of the family Gelechiidae. It is an oligophagous insect that feeds on the plant family Solanaceae and is especially known for being a major pest of potato crops. Currently farmers utilize insecticides, parasites, and sprinkler irrigation in order to prevent P. operculella from infesting their croplands.
Delia flies are members of the Anthomyiidae family within the superfamily Muscoidae. The identification of different species of Delia can be very difficult for non-specialists as the diagnostic characteristics used for immature and/or female specimens may be inconsistent between species. Past taxonomic keys were not as comprehensive in their identification of Delia specimens; they were either too reliant on genetic characteristics, focused solely on a specific life stage, or were focused only on certain species. However current taxonomic keys aim to be more thorough by not only including morphological diagnostics for males, females, and immature specimens of various species, but also their genetic make-up or molecular barcode.
The diamondback moth, sometimes called the cabbage moth, is a moth species of the family Plutellidae and genus Plutella. The small, grayish-brown moth sometimes has a cream-colored band that forms a diamond along its back. The species may have originated in Europe, South Africa, or the Mediterranean region, but it has now spread worldwide.
The European corn borer, also known as the European corn worm or European high-flyer, is a moth of the family Crambidae which includes other grass moths. It is a pest of grain, particularly maize. The insect is native to Europe, originally infesting varieties of millet, including broom corn. The European corn borer was first reported in North America in 1917 in Massachusetts, but was probably introduced from Europe several years earlier. Since its initial discovery in the Americas, the insect has spread into Canada and westward across the United States to the Rocky Mountains.
Spodoptera litura, otherwise known as the tobacco cutworm or cotton leafworm, is a nocturnal moth in the family Noctuidae. S. litura is a serious polyphagous pest in Asia, Oceania, and the Indian subcontinent that was first described by Johan Christian Fabricius in 1775. Its common names reference two of the most frequent host plants of the moth. In total, 87 species of host plants that are infested by S. litura are of economic importance. The species parasitize the plants through the larvae vigorous eating patterns, oftentimes leaving the leaves completely destroyed. The moth's effects are quite disastrous, destroying economically important agricultural crops and decreasing yield in some plants completely. Their potential impact on the many different cultivated crops, and subsequently the local agricultural economy, has led to serious efforts to control the pests.
Agrotis ipsilon, the dark sword-grass, black cutworm, greasy cutworm, floodplain cutworm or ipsilon dart, is a small noctuid moth found worldwide. The moth gets its scientific name from black markings on its forewings shaped like the letter "Y" or the Greek letter upsilon. The larvae are known as "cutworms" because they cut plants and other crops. The larvae are serious agricultural pests and feed on nearly all varieties of vegetables and many important grains.
Spodoptera littoralis, also referred to as the African cotton leafworm or Egyptian cotton leafworm or Mediterranean brocade, is a species of moth in the family Noctuidae. S. littoralis is found widely in Africa, Mediterranean Europe and Middle Eastern countries. It is a highly polyphagous organism that is a pest of many cultivated plants and crops. As a result, this species was assigned the label of A2 quarantine pest by the EPPO and was cautioned as a highly invasive species in the United States. The devastating impacts caused by these pests have led to the development of both biological and chemical control methods. This moth is often confused with Spodoptera litura.
Synanthedon myopaeformis is a moth of the family Sesiidae and the order Lepidoptera. In Europe it is known as the red-belted clearwing and in North America as the apple clearwing moth. The larvae create galleries under the bark of fruit trees, especially old trees with damaged trunks. During this process, the larvae cause significant damage to host trees. Particular attention has been paid to the damage they cause to apple trees. Their status as a pest of apple orchards has led to many research projects aimed at controlling populations of the moth. This moth is native to Europe, the Near East and North Africa. Recently, the moth was introduced into North America, being first detected in Canada in 2005. There are several organisms that threaten the larvae, including parasitoids, nematodes, and bacteria.
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