Light brown apple moth

Light brown apple moth adults are variable in colour and may be confused with other leafroller moths and similar species. DNA analysis is currently required to positively identify the species which are otherwise indistinguishable on gross characteristics from other moths of similar species. Typical males have a forewing length of 6–10 mm with a light brown area at the base, which is distinguishable from a much darker, red-brown area at the tip. The latter may be absent, with the moth appearing uniformly light brown, as in the females, which have only slightly darker oblique markings distinguishing the area at the tip of the wing. Females have a forewing length of 7–13 mm.

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  Female, dorsal view
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  Female, ventral view
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  Male, dorsal view
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  Male, ventral view

Larvae are not easily distinguished from the larvae of other tortricid leafrollers; only DNA testing is a certain identification method. The first larval instar has a dark brown head; all other instars have a light fawn head and prothoracic plate. Overwintering larvae are darker. First instar larvae are approximately 1.6 mm long, and final instar larvae range from 10 to 18 mm in length. The body of a mature larva is medium green with a darker green central stripe and two side stripes.

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  E. postvittana 5th instar larva
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Females release a specific blend of sex pheromone to attract males. The blend is a mixture of two compounds (E)-11-tetradecen-1-yl acetate, comprising 95% of the mixture and (E,E)-9,11-tetradecadien-1-yl acetate comprising the remaining 5%.[3] As an attractant used in moth traps, the synthetic versions of these pheromones are highly specific. Only very closely related species of moths are attracted to the pheromone's scent.[4]

The moth is native to Australia,[12] and its natural predators keep the population in check. It is a pest in New Zealand where various measures, including using natural enemies, insecticides and pheromones (to disrupt mating), have been taken for more than a decade.[13]

Natural enemies of the moth include species of tachinid fly and ichneumonid wasp. These are parasitoids which deposit their eggs on or within the bodies of the moth larvae. The parasitoid larva hatches and consumes the interior of the moth larva's body, killing the pest larva. Historically, the most abundant parasitoid has been the braconid wasp Dolichogenidea tasmanica, and it is still the most common natural enemy found with the moth in New Zealand.[14] This wasp, like the moth, is native to Australia and was probably imported along with it.[14] Other common parasitoids include the tachinid fly Trigonospila brevifacies, the braconid wasp Glyptapanteles demeter, and the bethylid wasp Goniozus jacintae.[14] The combination of these parasitoids have played a role in reducing moth damage.[14]

It is unknown how long LBAM has been present in California, though the first was identified in early 2007,[15] and widespread confirmed insect captures had been found across much of the coastal region of the state soon after. By 2008, almost 20,000 moths had been found in California, and more than half of them were in Santa Cruz County.[16] The California Department of Food and Agriculture and other organizations were concerned that the moth could cause more than half a billion dollars' worth of damage to California's crops if left unchecked.[17]

After the moth was confirmed to be present in California according to DNA testing, quarantine programs to prevent the spread of the Class A pest required farmers to pay for additional agricultural inspections and made it difficult to ship fruits and vegetables to other areas.[18] Soon after, a controversial program of aerial spraying proprietary synthetic pheromones over urban and suburban areas was planned. This was expected to be a five- to seven-year program.[19] USDA officials obtained an Emergency Exemption from Registration from the U.S. Environmental Protection Agency that allowed them to bypass state rules for the use of pesticides,[20] such as the production of an environmental impact report, that would normally be required. Less controversial efforts included nursery and grower treatment of potential infestations in plants using graduated integrated pest management (IPM) techniques with insecticides, smothering oils, and biologic controls such as Bacillus thuringiensis.

Public outcry over the aerial spraying plans was significant and centered on a fear of unknown health effects as well as general distrust of the government's claims that control measures were necessary and that the pheromone would be safe.[21] After duplicates were removed, 453 complaints of adverse health effects in humans were received.[22][23][24] However, many of the complaints were received when the spraying had been unexpectedly postponed due to fog[25] and provided incomplete information,[22] and the overall number of reports were small compared to the number of adults who would be expected to experience symptoms like irritated eyes or wheezing during a typical week,[26][27][28] leading many, including a judge hearing a lawsuit about the spraying,[29] to conclude that the reports were unrelated to spraying. In June 2008, the California Department of Food and Agriculture announced that it was abandoning plans for aerial spraying over population centers in favor of using local application of pheromone-impregnated twist-ties, a control measure that had proven effective in New Zealand.[30] In December 2015, an appeals court ruled against the LBAM pesticide program on the grounds that it violated state environmental laws.[31]

Five years after the first light brown apple moth was found in California, the state eliminated funding for inspection and monitoring, due to the statewide budget problems in 2012.[15] The federal government funded the inspection program, and farmers were left to use pesticides to kill moth infestations at their own expense.[15]