18 Plant Protection Quarterty VOI.5( 1) 1990 Molloy's records and NZLRI data arises be· ca use the NZLRI mapping failed to record Prospects for the biological control of Rosa rubiginosa R. mbiginosa where it was only a minor com­ (Sweet Brier) in New Zealand ponent of vegetation, or where it occurred in smalilocaliscd peekets. Hu nt er ( 1983) noted that R. mbiginosa P. Syrett, DSIR Plant Protection, Christchurch, New Zealand was most prominent in areas with less than • 1400 mm rainfall per annum on soils with a pronounced seasonal moisture deficit. On Summary tribution has been mapped using the M olesworth Station, it was particularly abun­ There has been renewed interest in the im­ NWASCO (Natioinal Water and Soi l Con· dant in areas with rai nfall less than 750-1000 plementation of a program for the biological serva tion Organi7..at ion) Ncw Zealand Land mm per annum (S tevens and Hughes 1973). control of Rosa rubiginosa (swcct bricr) from Resource Invent ory (NZLRI) (Hunter T he authors commented, however, that its high country pastoral farmers in the South (983). R. mbiginosa was recorded as present abundance might be related more to sparse Island of New Zealand. This has led to the on 443,800 ha of the South [sland, typically cover by ot her plants than as a result of a reassessment of early exploratory work: in associated with unimproved pasture and light preference for dry sites. This view is su p­ Europe and the preparation of an economic scrubland. Concentratcd infcstations oc­ ported by the especia lly high density and bet· evaluation of a biological control program. curred in inland M arlborough, sou th Canter­ ter growth of R. mbiginosa in locally damp Extensive work was carried Qut in the bury and inland O tago. Resu lts of a survey areas such as stream gullies. Molloy (1976) 1960s to identify from Europe which carried out by l3ascand and Jowett (1982) found that plants occurred to a maximum might be suitable for introduction into New showed a similar distribution. I-I owever, M ol­ altitude of 750- 1200 m a.s. 1. but Stevens and Zealand. The results of this work arc sum­ loy ( l964a) has recorded that by the 1960s it Hughes ( 1973) noted that their vigour was marized here and used in conjunction with was prese nt in almost every county through­ not affected by altitude to at least 1200 m information on the current status of R ru­ out the country. loc discrepancy between a.s.l. biginosa in New Zealand to discuss the bene­ fits and difficulties of reactivating a biological control program against this weed. The most promising species for introduction are the formers Diplo/epis rosae and D. mayri (: Cynipidae), lbe stem-mining buprcslid Agrilus aunchalceus (Coleoptera: Buprestidac), Nolocelia rosaeco/ana and EucosmD pauperana (Lepidoptera: Ole­ lhreutidae) whose larvae feed on buds and young shoots, and the lcafminer Tischera an­ gustico/e/Ja (Lepidoptera: Tischeriidae).

Introduction

Distribution and weed status of Rosa rubiginosa. Rosa mbiginosa L. is a European plant, oc­ curring from southern Sca ndinavia to north­ ern and eastern Spain. It is found eastwards into western Asia and north-west India and ·1 has become naturalised in North America (Clapham et at. 1987). It was recorded as a troublesome weed in South Africa by Neser and Annecke ( 1973), who reported it to be spreading along roads and banks, in grass­ land and mountain areas, and included it in a list of 17 exotic weed species under consid­ eration for biological control. In Australia R. nlbiginosa bas been re­ cordp.d as an important weed in southern New South Wales, South Australia, Tasma­ nia and Victoria (Parsons 1973), but no at· tempt has been made to control it biOlogi­ cally. In New Zealand R. mbiginosa (Figure I) was first recorded growing as a garden plant in 1835 (MOlloy 1964a), and, although widely used for ornamental purposes, was recog­ nized as a weedy species and classified as a noxious plant in 1900. It was probably initially imported as seed (MOlloy 1964a), and seeds are dispersed by grazing and by birds (Stevens and Hughes 1973). Its curreot dis· Figure 1. Rosa rubiginosa in pasture al Lake Pukaki, South Island, New Zealand. Plant Protection Quarterly VOI.5(1) 1990 19 Thickets of R. ntbiginosa usually develop (Meeklah and Mitchell 1973, 1981, Bristol Identification ofsuirable candidtues for in­ on the most fertile sites, occupying good po­ 1981, Meeklah and Cherry 1984), but m rroduction as biological conrrol agents. tential forage areas and preventing passage most situations this must be accompanied by of stock (Stevens and Hughes 1973). Thus a program of past ure improvement to pre­ Between 1962 and 1967 the Commonwealth on low productivity grasslands the weed can vent regrowth of suckers and seedlings. On Institute of Biological Cont rol (CIBC) in seriously deplete available pasture. Molloy much of the sparse, dry hill country where Delemont, Switze rland undertook a survey (1966) argued that populations of R. mbigi­ the weed is of greatest concern, this is either of prospective control agents for Rosa nosa had become static: spectacular in­ impractical or uneconomic. Two high cou n­ rubiginosa in Europe for the New Zealand creases in the early 1950s were the result of try runs in the Mackenzie country are suc­ Department of Scien tific and Indust rial Re­ rabbit control, (previously grazing by rabbits cessfully using goats to control the weed search (DSffi). and sheep had controlled the weed) but that (McKinnon 1982). As with other weed con­ About 450 insect species were reported as other plant cover also increased following trol programs employing goats this can be feeding on wild roses in Europe (Eichhorn the reduction in grazing pressu re, the com­ very effective provided that the land owner is 1967, Herting 1964, ScbrOder 1967, petitive advantage of R. ntbiginosa disap­ interested in farming goats. Scheibelreiter 1969, ZwOlfer 1964). The peared and few new plants established. He most promising species was the supported this theory by showing that many Insect fauna of Rosa rubiginosa in New rosae (L.) (Hymenoptera: Cynipi­ dae) which showed potential to be both dam­ existing sma ll plants were actually quite old Zealand aging and host specific. Other possibilit ies (Molloy 1967). Thus the problem was re­ The only specialised insect feeding on R. includedAgri/us aurichalceus Redt. (Coleop­ duced to the removal of existing plants. robiginosa in New Zealand is the rose seed tera: Buprestidae) and several microlepidop­ Although R. rnbiginosa may be relatively cbalcid Megastigmus aculeatus Swederus tera feeding on shoots and you ng foliage. easily contro lled where a good swa rd is main­ (Hymenoptera: Torymidae) a European in­ However, the project was terminated in 1%7 tained, and is not a problem in sown pasture sect which was probably introduced with and no introductions were made. (Molloy 1964a) it is still of major concern to seeds. No detailed assessment has been Many of the insects recorded from Rosa in farmers in some South Island areas Twenty­ made of its impact on seed production in Europe were generalist feeders and were five years after Molloy's work there are still New Zealand, although Molloy (l964b) re­ quiCkly eliminated from further considera­ many plants less than 25 years Old . [n a sur­ corded that typically 9% of seeds were in­ tion. ZWOlfer(I964) concluded that no Cole­ vey of South Island fa rmers ca rried out dur­ fested with larvae of M. acu/eatlls. Indica­ optera were restricted to the genus Rosa. He ing 1977 -8 (Bascand and Jowett I 982) R. rn­ tions from observations made in Europe noted, however, that A. aurichalceus was biginosa was perceived as a serious problem (Eichhorn 1967) are that the percentage of highly damaging to R. rubiginosa which was in Otago and Marlborough and had minor to seeds att acked there is very low (see belOW). the preferred host. As few as 20-30 larvae serious ratings in canterbury. In this same Eichhorn noted that infestation rates were were capable of severely damaging and even survey farmers ranked it fifth in importance higher in warmer areas indicating that it killing a shrub of R. rubiginosa. Although as a serious problem weed behind barley could be better suited to the New Zealand ZwOlfer collectedA. aurichalceus from other grass (Hordeum murinum), gorse (Ulex eu­ climate. However, all specimens collected wild Rosa spp. and suggested that it might ropaeus), nodding thistle (Carduus nutans) were from species of Rosa other than R ro­ also attack cultivated roses, he was unable to and broom (Cylisus scoparius). R. rnbiginosa biginosa, which does not appea r to be the substan tiate literature records from Rubus was top of the list of weeds of major eco­ preferred host (Kurir 1975). spp. by personal observation. SchrOder (pers. nomic significance to high country runhold­ Other phytophagous species which have comm.) has suggested that the A. aurichal­ ers surveyed in 1982 (Kerr and Lefever been recorded by Spiller and Wise (1982) cellS complex would be worth further investi­ 1984) with 52% of runs reporting this weed from R rnbiginosa in New Zea land include gation. A strai n specific to R rubiginosa of concern. From a questionnaire to rangers Macrosiphwn rosae (L.), the rose aphid, a could possibly be identified. of National Parks and Reserves it was re­ common and widespread pest of cu ltivated From among the Lepidoptera, Hymenop­ ported present in 10 out of 55 responses and roses; Chae/osiphon letrarhodum (Walker), tera and Diptera attaCking Rosa, Herting as a problem weed in one of these (S.M. another introduced aphid which occurs (1964) identified 55 species which rarely if Timmins pers. comm.). most ly on briers and rambler roses (Somer­ ever attacked other plants. Of the several Under the latest reclassification of noxious field 1984); Aulacospis rosae (BoucM), the species of microlepidoptera attacking buds plants (Noxious Plants Council 1985), R. ru­ introduced rose sca le; the cottony cushion and young foliage Nolocelia rosaecolana biginosa was declared a target plant by nine sca le, (Maskell) which has a leerya purchosi Dbld. (Olelhreutidae) was recorded most District Noxious Plants Authorities and as wide host range (Somerfield 1984); and the commonly from R. nlbiginosa and R spi. widespread in 28 DNPAs. In a survey of geometrid Zennizinga indocilisaria nosissima L. Eucosma pauperana Dup. (Ole­ DNPAs throughout New Zealand (including (Walker). The native longhorn beetle Gas­ threutidae) was uncommon, but recorded North Island districts where the weed is not trosanu nigricollis Bates can damage R. ro­ from wild roses and not cultivated ones, as generally of concern) R. mbiginosa was still biginosa by feeding in the stems, but has a was tbe leafminer, Tischera angrlSlicolella rated as the thirteenth most serious weed wide host range of native and introduced Dup. (Tischeriidae). (Syrett 1988). plants (SchrOder 1967). The sawnies Arge ochropa Gmel., A. pa­ The potential stock carrying capaCity of Insects rarely have a noticeable effect on gano Panz. and A. nigripes Retz. (Argidae) land infested with R. ntbiginosa is 1.7 million the vigour of R. ntbiginosa in New Zealand. were reportedly found on small, weak and ewe equivalents compa red to a current ca rry­ There have becn reports of damage of local­ isolated shrubs but not on vigorous and com­ ing capaCity of 0.6 million. Development of ised patches of the weed by the scarabaeid pact stands of wild roses. Although reports this land (a major r art of which would be beetles Pyronota fesliva (F.) (C.T. Jessep tha t they also attack Ribes and RubllS species control of R. ntbiginosa) could result in a pers. comm.) and Costelytra zealandica could not be substant iated, cultiva ted roses 175% increase in stock production (NZLRI, (White) (B.PJ. Molloy and J.D . Blair DSIR may be susceptible. A detailed study of the G.G. Hunter pers. comm.). files), bUllike G. nigricollis these species also rose-stem sawfly Syrista pan'eysii Spinola have a wide host range. Heavily defoliated (Cephidae) was ca rried out by Scheibelreiter Conrrol Methods plants are observed only rarely. Aphids never (1969). The damage it causes was found to Suitable herbicides and application methods approach densities commonly Observed on be much marc pronounced than that of any are available for control of R. mbiginosa cultivated roses. other rose sawfly, but alt hough restricted to W Planl Proleclion Quarterly VoI.5 (1) 1990

1967). It has only very rarely been observed on cullivaled roses. SchrOde r (1967) noted that ga lls were much more numerous on roses growing under stress ca used by drought. The climate of these areas in Eu­ rope closely matches Ihal of Ihose parIS of New Zealand where brier is a problem. Fac­ tors limiting the abundance of D. rosae in Europe wcre identified as the ability of the plant to suppress ga ll formation under gcxxl. growing conditions and the presence o f sev­ eral parasitic species which attack the larvae. On ave rage 75->80% of larvae were parasit­ ised (SchrOder 1967, Slille 1984). While fe­ males o f D. rosae ( the species is partheno­ genetic) are Short-lived, cold storage experi­ ments have shown tbat they can be obt ained

) rrom stored at any time so that rc­ Figure 2 Adull male, Megasligmus Figure 3. Female Megasligmus acu/ea­ phasing to southern hemisphere seasons acu/ealus Ius would be straightforward. Fecundity is high (> 700 eggs per female), so polential multi­ Rosa, S. parreysii preferred less thorny spe­ A detailed reporl was prepared on the ga ll plication rates are large. There is another cies and varieties o f roses indicat ing thai it wasp Dip/olepis rosae (SchrOder 1967). All species, Diplolepis mayri (Schlechtendal), would attack cultivated roses at least as read­ members of the genus Diplolepis induce or­ wbich has been shown to comprise two dis­ ily as R. mbiginosa. Seve n species of Ten­ ga n specific ga lls on species of Rosa only lincl species (Stille 1985). 1bey are indistin­ thredinidae whose hOSI specificity required (Shorlhouse 1982). D. rosae fo rms conspicu­ gu isha ble in the field. O ne of these species further clarification were reported as possi­ Ous 'mossy' ga lls in place of leaves and shoot (D. mayri L) is restricted to R. mbiginosa, bilities. Two species of ga ll forming insects, a tips. The resulting die-back of branches and was not fou od on other rosc species. cynipid Dipla/epis rasae (see belOW) and a sometimes kills the whole bush. I have seen Both species D. mayri Land D. mayri UK cecidomyiid, Wa chtliella rosanun Hardy, ga lls on R. nlbiginosa in the Wilamelle Val­ produce ga lls which arc smaller than those of were considered likely 10 be sufficienlly hosl ley, Oregon, US which had severcly st unled D. rasae, and no t hairy. Both species of D. speci fic to warrant further study. plant growth. Although D. rosae has been re­ mayri are pa rasilised by the sa me species Species attacking rose hips were studied by corded from many species of wild roses in which attack D. rosae. '[be main factor Eichhorn ( 1967). Two rose hip mOlhs, Gra· Europe, it is unlikely that all records are reli­ limiting Diplo/epis spp. in E urope is the pha/ita tenebrasana (Dup.) (Olclhrculidac) able since identificat ion of wild roscs in their ichncumonid Orthopeima mediator (Thun­ and Carposina scirhasella (H.S.) (Carposi­ non-flowering stages is very difficult. D. rosae be rg). If Dipo/epis spp. were established wilh­ nidae), and a fly , Carpomyia schineri (Loew) has been recorded mosl frequenlly from R. out this parasitoid it might have sufficient (Trypelidae), were more common in regions mbiginosa, R. canina L. and the very closely impact on R. rubiginosa to be an effective with warm dry summers, similar to (hose related R. dmnetonlln Thuill. (Schr6der control agent. parts o f N ew Zealand where brier is a prob­ lem. A Irypelid, Rlwgaletis altemata (Fallen), which is adapted lOcooler conditions, was the most abundant with larvae being found in 18.5% of hips. More parasil es were reared from G. lenebrosana than from other species indicating that if introduced into New Zea­ land free of these parasites its performance might increase more than that o f other spe­ cies. These insects were collected from a number of Rosa species, and are probably confined to tbe genus Rosa. It was thought tbat attack of cull iva ted roses by seed feeders could be tolerated and so less attention was paid to host specificity in these studies. Eichhorn ( 1967) indi cllled Ihal Megastigmlls aCllleatlls (Figure 2,3)could be the mOSI effi­ cient control agent as it destroyed the seed completely(Figure 4). He found Ihal Ihe in ­ festation rale (8% of hips and 0.6% of ach­ enes) was very low in Europe, however, and gave no explanation for this. From popula­ tions in Austria Kurir (1975) recorded infes­ tation rales of hips from 28% 10 92%. It is possible Ihal higher infestalion rales mighl be achieved in New Zealand by using st.rains of M. aelliealllS particularly adapted toR. ru­ biginosa, and also matched climatica lly. Figure 4. Seeds of Rosa rubiginosa deslroyed by lava of Megastigmus acu/ea/us Plant Protection QuarterlyVoI.5(1) 1990 21 In Sweden D. rosae and D. mayr; do not the project in New Zealand it had to be aban­ Grundy, T.P. (1989). An economic evalu­ coexist on the same rose bush and in some doned. ation of biological control of sweet brier. localities do not attack the same species The need for detailed host specificity work Agribusiness and Economics Research (Stille pers. comm.). In several localities D. as a basis for resolving conflicts of interest Unit, Research Report No. 201, Lincoln rosae bas been found only on R. canina and should have been anticipated at the outset, College, CanterbUry, New Zealand. D. mayri only on R. robig;nosa. This sug­ and a committment gained that adequate Herting, B. (1964). Lepidoptera, Hymenop­ gested to Stille that D. mayr; might have a quarantine facilities be made available for tera and Diptera attacking Rosa in Eu­ 1 competitive advantage over D. rosae on R. carrying out some of this work. Molloy's rope. Commonwealth Institute of Biologi­ rnbiginosa, a possibility which should be (l964a) conclusion that R. rnbiginosa was cal Control. Unpublished report. taken into account before making a decision highly amenable to control by pasture man­ Hunter, G.G. (1983). An assessment of the J to release any of these species in New Zea­ agement was interpreted as a solution to the distribution of sweet brier (Rosa rubigi­ land. problem, and emphasises the importance of nosa) in New Zealand. New Zealand Jour­ obtaining reliable information about a weed nal of Experimental Agricullllre 11, 181- Discussion before embarking on an expensive control 188. In spite of the efforts that have gone into project. Kerr, I.G.C. and Lefever, K.R. (1984). High control by use of herbicide and pasture man­ Today R. nlbiginosa is still a problem scrub Country Farming 1966-1982. Tussock agement over the last 20 years, R. rnbiginosa weed in New Zealand particularly in areas Grasslands and Mountain Lands Institute is still classified as a noxious plant by 37 dis­ where control by chemicals and pasture im­ Review 42, 59-82. trict noxious plants authorities in New Zea­ provement is uneconomic. In such situations Kurir, A (1975). Zur kenntnis von Megas­ land. Because so much of the exploratory biological control is an attractive option. An tigmus aCll/entlis Swed. (Hym. Chalcid., work has been done, morc information economic evaluation of the biological control Torymidae), eins Samenzerstorers bei der about potential control agents is available on of R rubiginosa has shown that savings as Hundsrose (). ZeitschriJt fur which to base a decision than is the case for high as $4 million per year might be achieved Angewand/e Emomologie 78, 415-423. most other weeds. (Grundy 1989). Using assumptions and McKinnon, D. (1982). Angoras clobber The biological control program against R. probabilities to present a most likely out­ sweet brier. New Zealand Fanner 9,17-22. nlbiginosa was terminated after many scien­ come, Grundy has estimated that the costs of Meeklah, FA and Cherry, J. (1984). The tist years of work without the introduction a biological control program would be recov­ effect of time of application of hexazinone into New Zealand of a single insect species. ered 13 years after the release of the first on the control of sweet brier. Proceedings Several reasons have been given for this, and control agents. Extensive host specificity test­ of the 37th New Zealand Weed and Pest in reality a number of factors contributed to ing would be required to demonstrate the Control Confercnce, 203-5. the decision. safety of the agents to closely related crop, Meeklah, FA and Mitchell, RB. (1973). Resulls of Molloy's (l964a, 1966) studies garden and native plants. There are no Rosa The economics of sweet brier control. Pro­ indicated that R. nlbiginosa was a less serious species native to New Zealand, but 5 species ceedings of the 26th New Zealand Weed weed than had been thought previously, and, of Rubus are endemic as are 14 species of and Pest Control Conference, 34-8. at the same time, research emphasis in Ento­ Acaena and the single species of Potentilla. Meeklah, FA and Mitchell, RB. (1981). mology Division, DSIR was being directed Of 7 species of Gewn, 4 are endemic (Webb Evaluation of the spot gun technique for towards the study of pasture pests. The par­ et at. 1988). There are, however, some prom­ control of sweet brier. Sixth Australian ticular difficulties of working on a rosaceous ising insect agents which may be both damag­ Weeds Conference, 99-103. species had been inadequately considered at ing and sufficieoUy host speCific. These in­ Molloy, B.P J. (l964a). Sweet brier -A vigor­ the outset of the project. It was imponant clude the gall formers Diplolepis rosae and D. ous woody weed in South Island tussock that any insect selected as a potential control mayri (Cynipidae), the stem boring Agrilus grassland. New Zealand Journal of Agri­ agent be not only damaging to the host plant aurichalceus (Buprestidae), Notocelia rosae­ cllllllre 109, 105-118. but also highly specific to it. Rosa spp. have cotana and Eucosma pauperana (Olethreuti­ Molloy, B.P J. (l964b). Synopsis of struc­ many relatives among horticultural crop dae) which allack buds and young shoots, ture, life history and seasonal behaviour of plants (e.g. Rubus, MahlS, Prunus etc), and and the leaf mining Tischera angusticolella sweet brier. Proceedings of the 17th New many forms of Rosa are grown as garden (Tischeriidae). Zealand Weed and Pest Control Confer­ plants, including some true species. Thus ence,19-27. careful and lengthy host specificity testing References MOllOY, B.P.1. (1966). Sweet brier - status would have been required as well as secure Bascand, LD. and Jowell, G.H. (1982). and trend in the South Island. Soil and Wa­ quarantine facilities in New Zealand in which Scrubweed cover of South Island agricul­ ter3(2) 11-12. to conduct some of this work. Diplolepis ro­ tural and pastoral land. 2. Plant distribu­ Molloy, B.P J . (1%7). How old is your sweet sae would probably have been introduced tion and managerial problem status. New brier? Tussock Grasslands and Mountain into New Zealand in 1965 had suitable quar­ Zealand Journal of Experimemal AgriCl/l­ Lands Institute Review 12, 1-7. antine facilities been available (B.B. Given, /lire 10, 455-492. Molloy, B.P.1. (1976). An analysis of sweet DSIR files) but in May 1%7 these had still Bristol, RW. (1981). Control of sweet brier brier on Molesworth. pp. 90-110 In "lbe not been built. Disquiet was expressed by the using picloram , triclopyr and 2,4,5-T ap­ Changing Vegetation of Molesworth Sta­ National Rose Society of New Zealand in plied with modified drench gun. Proceed­ tion", Ed Moore LB. New Zealand. DSIR 1966 as to the possible effects on cullivated ings of the 34th New Zealand Weed and Bulletin 217, Wellington. 118 pp. roses, (DSIR files) and when SchrOder Pest Control Conference, 144-7. Neser, S. and Annecke, D.P. (1973). Biologi­ (1%7) recorded that galls had, under very Clapham, AR.; Tutin, T.G.; Moore, D.M. cal control of weeds in South Africa. De­ exceptional circumstances, been found on (1987). Flora of the BritiSh Isles. 3rd Edi­ partment of Agricullural Technical Serv­ cultivated roses, this provided a good reason tion. cambridge University Press. ices, Pretoria. for abandoning the project. There were still Eichhorn, O. (1967). Insects allacking rose Noxious Plants Council (1985) Plant classifi­ several avenues of work that could profitably hips in Europe. Commonwealth Institute cation: decisions and supporting state­ have been pursued, but with neither quaran­ of Biological Control Technical Bulletin ments for plants submitt,ed for classifica­ tine facilities nor adequate staff assigned to No.8, 83-97. tion. Unpublished report April 1985. 22 Plant Protection Quarterly VOL5( 1) 1990 Parsons, W.T. (1973). "Noxious weeds of Somerfield, K.G . (1984). Greenouse and Stille, B. (1985). Host plant specifiCity and Victoria". Inkata Press Melbourne. ornamental pests In "New Zealand pest allozyme variation in the parthenogenetic Scheibel reiter, G. ( 1969). Observations on and beneficial insects". (Ed. Scott, R.R.). gall wasp Dip/o/epis moyri and its relat­ the biology and ecology of the rose-stem Lincoln University College of Agriculture. edness to D. rosae (Hymenoptera: sawfly (Syrislo paTTeysii Spinola (Hym. Spiller, D.M. and Wise, K.A.J. (1982). A Cynipidae). Entom%gia Genera/is 10, 87- Cephidae) in Europe. Commonwealth In­ catalogue (1860-1960) of New Zealand 96. stitute of Biological Control Technical Insects and their host plants. DSIR Bulle­ Syrett, P. (1988). Priority weeds for biologi­ Bulletin No. 12, 105-114. tin 231 Wellington. cal COntrol research. Proceedings of the SchrOder, D. (1967). Dip/o/epis (=Rhodiles) Stevens, EJ. and Hughes, J.G. (1973). Dis­ Institute of Noxious Plants Officers Con­ rosae (L.) (Hym.: Cyn ipidae) and a review tribution of sweet brier, broom and ference, New Plymouth, New Zealand. 2-4 of its parasite complex in Europe. Com­ ragwort on Molesworth Station. Tussock May 1988. monwealth Institu te of Biological Control Grasslands and Mountain Lands Institute. Webb, c.J., Sykes, W.R., Garnock-Jones, Technical Bulletin No. 9, 93-131. Special Publication NO.9 PJ. (1988). ·F1ora of New Zealand Vol­ Short house, J.D. (1982). Resource exploita­ Stille, B. (1984). The effect of host plant and ume IV. Botany Division DSIR, Christ­ tion by gall wasps of the genus Diplo/epis. parasitoids on the reproductive success of church, New Zealand . Proceedings of the 5th International Sym­ the parthenogenetic gall wasp Diplo/epis ZwOlfer, H. (1964). Coleoptera attacking posium on Insect-Plant Relationships, rosae (Hymenoptera:Cynipidae). Oecolo­ Rosa in Europe. Commonwealth Institute 193-198. gia 63, 364-369. of Biological Control. Unpublished report.