Rhagoletis completa (walnut husk fly)
Index
- Pictures
- Identity
- Taxonomic Tree
- Notes on Taxonomy and Nomenclature
- Description
- Distribution
- Distribution Table
- Risk of Introduction
- Habitat
- Hosts/Species Affected
- Host Plants and Other Plants Affected
- Growth Stages
- Symptoms
- List of Symptoms/Signs
- Biology and Ecology
- Natural enemies
- Notes on Natural Enemies
- Means of Movement and Dispersal
- Pathway Vectors
- Plant Trade
- Impact
- Diagnosis
- Detection and Inspection
- Similarities to Other Species/Conditions
- Prevention and Control
- References
- Distribution Maps
Don't need the entire report?
Generate a print friendly version containing only the sections you need.
Generate reportPictures
Top of pageIdentity
Top of pagePreferred Scientific Name
- Rhagoletis completa Cresson
Preferred Common Name
- walnut husk fly
Other Scientific Names
- Rhagoletis suavis completa Cresson
- Rhagoletis suavis var. completa Cresson
International Common Names
- English: husk maggot
- French: mouche des brous du noyer
Local Common Names
- North America: husk maggot
- Germany: Amerikanische Walnussschalen-Fliege; Fliege, Amerikanische Walnussschalen
EPPO code
- RHAGCO (Rhagoletis completa)
Taxonomic Tree
Top of page- Domain: Eukaryota
- Kingdom: Metazoa
- Phylum: Arthropoda
- Subphylum: Uniramia
- Class: Insecta
- Order: Diptera
- Family: Tephritidae
- Genus: Rhagoletis
- Species: Rhagoletis completa
Notes on Taxonomy and Nomenclature
Top of pageDescription
Top of pageDiagnostic features of the genus are as follows (characters extracted from key to North American genera of Tephritidae by Foote et al., 1993): Head with two pairs orbital setae; posterior pair reclinate. Gena with only short anterior setae. First flagellomere (third antennal segment) at least slightly pointed at the apex. Thorax with dorsocentral setae closer to level of anterior supra-alar setae than transverse suture. Scutellum not swollen or shiny. Wing with cells bm and bcu of similar depth; bcu with a short acute extension. Crossvein R-M near middle of cell dm.
This species may be identified using the Diptera key in the Crop Protection Compendium taxonomic identification aid. For full details of its separation from other North American species, see Foote et al. (1993).
The main features of R. completa are as follows: thorax and abdomen predominantly pale yellow to orange. Wing with a distinct subbasal crossband; discal and preapical crossbands usually separate. Mediotergite dark marked (either entirely dark brown or with a pair of brown stripes). For more comprehensive details see Foote et al. (1993).
Larva
Diagnosis of genus by Elson-Harris (White and Elson-Harris, 1994): Antennal sensory organ with a short basal segment and cone-shaped distal segment; maxillary sensory organ flat, with well defined sensilla surrounded by small cuticular folds; stomal sensory organ rounded, with a peg-like sensilla; large, preoral teeth near base of stomal sensory organ; no preoral lobes; oral ridges in 5-13 short, unserrated rows; no accessory plates. Stout spinules forming discontinuous rows on almost all segments. Anterior spiracles with 7-35 stout tubules. Posterior spiracular slits 3-8 times as long as broad, with 3-16 short, branched spiracular hairs. Anal lobes large, protuberant with well defined tubercles and sensilla.
There is no modern description of the larva of this species (in the sense of SEM studies being applied). However, Steyskal (1973) provided a key for the separation of the larvae of three species found in walnut. Any Rhagoletis larvae found in walnuts and having the following features is likely to be this species: 16-21 tubules, in each anterior spiracle; upper and lower slits of the posterior spiracles at about 60 degrees to each other. See key to larvae in White and Elson-Harris (1994), which used a combination of host and fragmentary morphological data.
Distribution
Top of pageHarris (1989), Foote et al. (1993) and CABI (1997) all provide distribution maps.
Distribution Table
Top of pageThe distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.
Last updated: 12 May 2022Continent/Country/Region | Distribution | Last Reported | Origin | First Reported | Invasive | Reference | Notes |
---|---|---|---|---|---|---|---|
Europe |
|||||||
Belgium | Present, Localized | ||||||
Bosnia and Herzegovina | Present | ||||||
Croatia | Present | Introduced | 2003 | ||||
Czechia | Present, Localized | ||||||
France | Present, Localized | ||||||
-Corsica | Present, Localized | ||||||
Germany | Present, Localized | ||||||
Hungary | Present, Localized | ||||||
Italy | Present, Localized | ||||||
Netherlands | Present, Few occurrences | ||||||
Poland | Present | ||||||
Slovakia | Present, Few occurrences | ||||||
Slovenia | Present, Localized | 1997 | |||||
Spain | Present, Few occurrences | Girona. | |||||
Switzerland | Present, Widespread | 1986 | |||||
United Kingdom | Absent, Confirmed absent by survey | ||||||
North America |
|||||||
Canada | Present, Localized | ||||||
-British Columbia | Present, Localized | ||||||
Mexico | Present, Localized | ||||||
United States | Present | Introduced | 1916 | ||||
-Arizona | Present | ||||||
-California | Present, Few occurrences | ||||||
-Colorado | Present | ||||||
-Idaho | Present | ||||||
-Iowa | Present | ||||||
-Kansas | Present | ||||||
-Minnesota | Present | ||||||
-Mississippi | Present | ||||||
-Missouri | Present | ||||||
-Nebraska | Present | ||||||
-Nevada | Present | ||||||
-New Mexico | Present | ||||||
-Oklahoma | Present | ||||||
-Oregon | Present | ||||||
-Texas | Present | ||||||
-Utah | Present | ||||||
-Washington | Present | ||||||
Oceania |
|||||||
New Zealand | Absent, Confirmed absent by survey |
Risk of Introduction
Top of pageHosts/Species Affected
Top of pageHost Plants and Other Plants Affected
Top of pagePlant name | Family | Context | References |
---|---|---|---|
Crataegus laevigata | Rosaceae | Unknown | |
Juglans (walnuts) | Juglandaceae | Unknown | |
Juglans californica (california walnut) | Juglandaceae | Main | |
Juglans hindsii (californian black walnut) | Juglandaceae | Main | |
Juglans hirsuta | Unknown | ||
Juglans major (arizona walnut) | Juglandaceae | Unknown | |
Juglans microcarpa (River walnut tree) | Juglandaceae | Unknown | |
Juglans mollis | Juglandaceae | Unknown | |
Juglans nigra (black walnut) | Juglandaceae | Main | |
Juglans regia (walnut) | Juglandaceae | Main | |
Malus domestica (apple) | Rosaceae | Unknown | |
Prunus persica (peach) | Rosaceae | Other |
Symptoms
Top of pageList of Symptoms/Signs
Top of pageSign | Life Stages | Type |
---|---|---|
Fruit / discoloration | ||
Fruit / extensive mould | ||
Fruit / gummosis | ||
Fruit / internal feeding | ||
Fruit / lesions: black or brown | ||
Fruit / lesions: scab or pitting | ||
Fruit / obvious exit hole | ||
Fruit / odour | ||
Fruit / ooze |
Biology and Ecology
Top of pageFor development rates at various temperatures see Kasana and AliNiazee (1994).
Natural enemies
Top of pageNatural enemy | Type | Life stages | Specificity | References | Biological control in | Biological control on |
---|---|---|---|---|---|---|
Biosteres sublaevis | Parasite | Arthropods|Larvae | ||||
Coptera occidentalis | Parasite | |||||
Trybliographa sp. | Parasite | Arthropods|Larvae |
Notes on Natural Enemies
Top of pageMeans of Movement and Dispersal
Top of pagePathway Vectors
Top of pageVector | Notes | Long Distance | Local | References |
---|---|---|---|---|
Clothing, footwear and possessions | Fruit in case or handbag. | Yes | ||
Containers and packaging - wood | Of fruit cargo. | Yes | ||
Land vehicles | Lorries, aeroplanes and perhaps ships, with fruit cargo. | Yes | ||
Fruit in post. | Yes | |||
Soil, sand and gravel | Risk of puparia in soil. | Yes |
Plant Trade
Top of pagePlant parts liable to carry the pest in trade/transport | Pest stages | Borne internally | Borne externally | Visibility of pest or symptoms |
---|---|---|---|---|
Fruits (inc. pods) | arthropods/eggs; arthropods/larvae | Yes | Pest or symptoms usually visible to the naked eye | |
Growing medium accompanying plants | arthropods/pupae | Yes | Pest or symptoms usually visible to the naked eye |
Plant parts not known to carry the pest in trade/transport |
---|
Bark |
Bulbs/Tubers/Corms/Rhizomes |
Flowers/Inflorescences/Cones/Calyx |
Leaves |
Roots |
Seedlings/Micropropagated plants |
Stems (above ground)/Shoots/Trunks/Branches |
True seeds (inc. grain) |
Wood |
Impact
Top of pageIn California it causes two types of damage. In populations causing normal or late-season infestations, larval feeding causes the whole husk or large portions of it to turn black, seriously reducing the value of nuts sold in the shell although the kernel is undamaged. Attack by populations involved in early infestations impedes the maturation of the kernel and results in shrivelled nuts or empty shells (Hislop et al., 1981).
Detection and Inspection
Top of pageSimilarities to Other Species/Conditions
Top of pagePrevention and Control
Top of pageDue to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.
Upon detection, fallen and infected fruit must be removed and destroyed. If possible, wild and abandoned host trees should also be destroyed. Boller and Prokopy (1976) note that systemic organophosphates, such as dimethoate, are highly effective against most species, killing eggs, larvae and adults. Belanger et al. (1985) discussed the use of pyrethroids, but these were only of use when pest activity was low. More environmentally acceptable techniques have been tried; namely bait sprays (insecticide plus ammonia source) which can be applied as a spot treatment; soil application of insecticide to destroy pupae; and juvenile hormone analogues which can be applied to the soil (Boller and Prokopy, 1976). The IPM of walnut pests, including R. completa, was discussed by Haley and Baker (1982). Early harvest can be used to avoid attack (Yokoyama and Miller, 1996). Some varieties may be more susceptible to attack than others. Shelton and Anderson (1990) compared four varieties and found that Hartley suffered less damage than early leafing varieties.
Consignments of fruits from countries where these pests occur should be inspected for symptoms of infestation and those suspected should be cut open in order to look for larvae. European and Mediterranean Plant Protection Organization (EPPO) recommended (OEPP/EPPO, 1990), when only the North American origin was under consideration, that such fruits should come from an area where R. completa does not occur or from a place of production subject to growing season inspection. Fruits may also be treated in transit by cold treatment (for example, 40-42 days at -0.6°C) (FAO, 1983); however, Yokoyama and Miller (1996) found that low temperature storage could not be used as a quarantine treatment alone for some crops (e.g. walnuts) because the fly tolerated the treatment better than the host. Ethylene dibromide was previously widely used as a fumigant but is now generally withdrawn because of its carcinogenicity. Treatment methods against fruit flies are currently under review within EPPO and as part of an inter-RPPO programme.
Plants of host species transported with roots from countries where these pests occur should be free from soil, or the soil should be treated against puparia. The plants should not carry fruits. Such plants may indeed be prohibited from importation.
References
Top of pageArmstrong JW; Couey HM, 1989. Control; fruit disinfestation; fumigation, heat and cold. In: Robinson AS, Hooper G, eds. Fruit Flies; their Biology, Natural Enemies and Control. World Crop Pests. Amsterdam, Netherlands: Elsevier, 3(B):411-424.
Boller EF; Prokopy RJ, 1976. Bionomics and management of Rhagoletis. In: Smith RF, Mittler TE, Smith CN, ed. Annual review of entomology. Volume 21. Annual Reviews Inc. Palo Alto, California, USA, 223-246.
Boyce, A. M., 1934. Bionomics of the walnut husk fly (Rhagoletis completa). Hilgardia, 8, 363-579.
Bush GL, 1966. The taxonomy, cytology and evolution of the genus Rhagoletis in North America (Diptera: Tephritidae). Bulletin of the Museum of Comparative Zoology, 134:431-526.
Christenson LD; Foote RH, 1960. Biology of fruit flies. Annual Review of Entomology, 5:171-192.
Economopoulos AP, 1989. Control; use of traps based on color and/or shape. In: Robinson AS, Hooper G, eds. Fruit Flies; Their Biology, Natural Enemies and Control. World Crop Pests 3(B): 315-327. Amsterdam, Netherlands: Elsevier.
EPPO, 1990. Specific quarantine requirements. EPPO Technical Documents, No. 1008. Paris, France: European and Mediterranean Plant Protection Organization.
EPPO, 2011. EPPO Reporting Service. EPPO Reporting Service. Paris, France: EPPO. http://archives.eppo.org/EPPOReporting/Reporting_Archives.htm
EPPO, 2014. PQR database. Paris, France: European and Mediterranean Plant Protection Organization. http://www.eppo.int/DATABASES/pqr/pqr.htm
EPPO, 2016. EPPO Global database (available online). Paris, France: EPPO. https://gd.eppo.int/
FAO, 1983. International plant quarantine treatment manual. FAO Plant Production and Protection Paper No. 50. Rome, Italy: FAO.
Fletcher BS, 1989. Ecology; movements of tephritid fruit flies. In: Robinson AS, Hooper G, eds. Fruit Flies; Their Biology, Natural Enemies and Control. World Crop Pests, 3(B). Amsterdam, Netherlands: Elsevier, 209-219.
Foote RH; Blanc FL; Norrbom AL, 1993. Handbook of the Fruit Flies (Diptera: Tephritidae) of America North of Mexico. Ithaca, USA: Comstock.
Harris EJ, 1989. Pest status; Hawaiian Islands and North America, In: Robinson AS, Hooper G, eds. Fruit Flies; their Biology, Natural Enemies and Control. World Crop Pests. Amsterdam, Holland: Elsevier, 3(A):73-81.
IPPC, 2013. First report of Rhagoletis completa. IPPC Official Pest Report, No. HUN-02/1. Rome, Italy: FAO. https://www.ippc.int/
IPPC, 2016. First suspicion of Rhagoletis completa on Juglans regia in a private garden. IPPC Official Pest Report, No. NLD-46/1. https://www.ippc.int/en/
Steyskal GC, 1973. Distinguishing characters of the walnut husk maggots of the genus Rhagoletis (Diptera, Tephritidae). Cooperative Economic Insect Report, 23: 522.
Distribution References
Boyce A M, 1934. Bionomics of the walnut husk fly (Rhagoletis completa). Hilgardia. 363-579.
CABI, Undated. Compendium record. Wallingford, UK: CABI
CABI, Undated a. CABI Compendium: Status as determined by CABI editor. Wallingford, UK: CABI
IPPC, 2013. First report of Rhagoletis completa. IPPC Official Pest Report, No. HUN-02/1., Rome, Italy: FAO. https://www.ippc.int/
IPPC, 2016. First suspicion of Rhagoletis completa on Juglans regia in a private garden. In: IPPC Official Pest Report, No. NLD-46/1, https://www.ippc.int/en/
NHM, 1989. Specimen record from the collection in the Natural History Museum (London, UK)., London, UK: Natural History Museum (London).
NPPO of the Netherlands, 2013. Pest status of harmful organisms in the Netherlands., Wageningen, Netherlands:
Distribution Maps
Top of pageSelect a dataset
Map Legends
-
CABI Summary Records
Map Filters
Unsupported Web Browser:
One or more of the features that are needed to show you the maps functionality are not available in the web browser that you are using.
Please consider upgrading your browser to the latest version or installing a new browser.
More information about modern web browsers can be found at http://browsehappy.com/