Biocontrol introduction
Target pest: Coleophora spissicornis (Lepidoptera: Coleophoridae), banded clover casebearer
Agent introduced: Neochrysocharis trifolii (Hymenoptera: Eulophidae) = Chrysonotomyia trifolii, Closterocerus trifolii
Imported:
1961, 1962, 1967, 1968, 1969
Import source:
1961, 1969 near Freiburg, Germany; 1961, 1962, 1967, 1968, 1969 Avignon, France via Delémont, Switzerland
Import notes:
Cameron et al. (1989) - Neochrysocharis trifolii was imported in 1961, 1962, 1967, 1968 and 1969 under the name Neochrysocharis sp.; it was not considered the most desirable agent as its synchronisation with the host was thought to be less precise than others and it was not released until 1967. It was imported as field-collected, encased, fourth instar host larvae, either Coleophora frischella or C. deauratella. Coleophora deauratella, collected from near Freiburg, Germany, were imported in 1961 and 1969; C. frischella were collected from Avignon, France in 1961, 1962, 1968 and 1969 and reared in Delémont, Switzerland prior to shipping to New Zealand. Neochrysocharis trifolii emerging from the C. frischella material imported in 1961 were preserved as reference specimens. The 1962 shipment contained an estimated 70 N. trifolii mummies; emerging adults were left to die. The 1967 shipment contained 25 N. trifolii mummies; one male and 58 females emerged and were used to establish a laboratory culture, but the second generation contained only males. Wasps from the 1968 shipments were used to establish a culture; after three generations approximately 1,600 adults were released. The 1969 shipment was expected to contain about 100 N. trifolii mummies; adults were intended for direct field release and establishing a laboratory culture. The culture was an almost complete failure and release details were not recorded.
Released:
1967
Release details:
Cameron et al. (1989) - a single adult was released in 1967, though the location is not recorded. In 1968, 1,600 adults were released at Palmerston North, Manawatu in the North Island. It may have been released in 1969 but numbers and location were not recorded.
Establishment:
Cameron et al. (1989) - establishment was confirmed in January 1977 when two N. trifolii mummies were found in a collection of 253 C. frischella first generation larvae at Lincoln, Canterbury in the South Island, 450 km south of the Manawatu, North Island release site. By the following generation, in mid-March, parasitism had increased to 6.2% and by the first generation of 1978 to 27.8%. A survey in 1982 found N. trifolii established throughout Canterbury and Manawatu (North Island) with parasitism rates of 49.7% and 10.3% respectively.
Impacts on target:
Cameron et al. (1989) - of the parasitoids introduced against Coleophora spp. [C. frischella and C. spissicornis] only Bracon variegator [established in 1966] and N. trifolii have established. While they were not deemed the most desirable, in the absence of competition from the parasitoids more closely synchronised with the hosts B. variegator and N. trifolii have achieved the aim of controlling Coleophora spp. admirably. It is now rare for Coleophora spp. infestations in white clover seed crops to reach an economically damaging level or require control with insecticides.
Cameron et al. (1993) - Neochrysocharis trifolii, in conjunction with Bracon variegator [see the B. variegator introduction entry], is categorised as exerting “substantial” control (defined as “other control measures are only occasionally required”) over Coleophora spp. [C. frischella and C. spissicornis].
General comments:
Taxonomic note (22 October 2022) - this species was originally described in 1961 by Erdös as Neochrysocharis trifolii. Bouček (1988, in Hansson (1990)) synonymised Neochrysocharis with Chrysonotomyia, though Hansson (1990) considered Neochrysocharis to be a valid genus. Gumovsky (2001) synonymised Neochrysocharis with Closterocerus, but Burks et al. (2011) removed Neochrysocharis from synonymy with Closterocerus and reinstated it as a valid genus. Note that Hansson (1990) synonymised Neochrysocharis trifolii with N. formosa (now N. formosus), but both Broad (Hymenoptera of the British Isles checklist - accessed 22 October 2022) and Noyes (2019) (Universal Chalcidoidea Database - accessed 22 October 2022) consider these to be separate species.
References
Broad G (). Hymenoptera of the British Isles. https://ukhymenoptera.myspecies.info/
Burks RA, Heraty JM, Gebiola M, Hansson C (2011). Combined molecular and morphological phylogeny of Eulophidae (Hymenoptera: Chalcidoidea), with focus on the subfamily Entedoninae. Cladistics 27(6): 581-605 https://doi.org/10.1111/j.1096-0031.2011.00358.x
Cameron PJ, Hill RL, Bain J, Thomas WP (1989). A Review of Biological Control of Invertebrate Pests and Weeds in New Zealand 1874-1987. Technical Communication No 10. CAB International Institute of Biological Control. DSIR Entomology Division. 424p.
Cameron PJ, Hill RL, Bain J, Thomas WP (1993). Analysis of importations for biological control of insect pests and weeds in New Zealand. Biocontrol Science and Technology 3(4): 387-404
Gumovsky AV (2001). The status of some genera allied to Chrysonotomyia and Closterocerus (Hymenoptera: Eulophidae, Entedoninae), with description of a new species from Dominican amber. Phegea 29(4): 125-141
Hansson C (1990). A taxonomic study on the Palearctic species of Chrysonotomyia Ashmead and Neochrysocharis Kurdjumov (Hymenoptera: Eulophidae). Insect Systematics & Evolution 21(1): 29-52
Noyes JS (2019). Universal Chalcidoidea Database Natural History Museum. Last updated March 2019. http://www.nhm.ac.uk/chalcidoids
