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Biological control for weeds in Ireland with reference to JK & HB

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1 Biological control for weeds in Ireland with reference to JK & HB
Dick Shaw & Rob Tanner- CABI

2 Format Brief introduction to CABI and invasives
Biocontrol – types, history and examples Azolla weevil Japanese knotweed: and the psyllid Himalayan Balsam Floating Pennywort

3 What/who is CABI? Formerly the Commonwealth Agriculture Bureaux International, Origins back to 1910. UN-Treaty level, not-for profit intergovernmental organisation owned by its 45 member countries CABI includes the former International Institute of Biological Control (IIBC) and 3 other institutes

4 Our member countries and centres
CABI centre CABI member country

CABI improves people’s lives worldwide by providing information and applying scientific expertise to solve problems in agriculture and the environment KNOWLEDGE FOR LIFE

6 CABI Publishing Abstracts – environment, agriculture, tourism
7 million abstracts (10,000 free text added/yr) Books - 60 new titles/year Invasive Species Compendium >1,000 species included so far (hopefully open access if final funding can be found) £20 million turnover Only 5% of our income is from member contributions (“core funding”)

What about the really big problems we already have?

8 Plants are often the worst invaders

9 What is Biological Control?


11 Broom in New Zealand

12 3 Categories of Biological Control
Conservation - Protection and maintenance of existing Natural Enemies (NEs) Inundative - a.k.a the “Mycoherbicide Approach” using native pathogens for repeated application Classical - Using Co-evolved (highly specific) NEs from the area of origin of the plant to provide self-sustaining control after a single release. There are three types of natural control or as the scientific literature would have it “Biological Control” I will mostly be talking about Classical. But let’s get the concept of a natural solution clear

13 Rhododendron ponticum
Can’t use the classical approach since there are 500 cultivars.


15 Buddleia pathogens

16 What is Classsical Biological Control?

17 NOT The Cane Toad

18 Cactoblastis cactorum

19 Prickly pear in Australia
50 million hectares of it in New South Wales Early last century the prickly pear covered 50 million acres which is about 30 times the size of Devon or most of the UK. Hard to conceive but it does show why countries like OZ, NZ and the US lead the way in natural control

20 50 million acres cleared and now exists in harmony with surrounding vegetation. Silver bullet
This resulted in about 250,000 square kilometres of agricultural land being cleared of prickly pear. By the mid 1930’s Prickly pear was no longer a problem. A Cactoblastis memorial hall was built to honour this successful moth Before

21 After


23 Rubber vine weed 60,000 hectares of Queensland infested
Green custard bringing down intact Eucalypt forest and threatening national parks but not the case in madagascar where the plant is from

24 Maravellia cryptostegia from Madagascar
screened in our fcility and eventaully cleared fro release and now native species are returning and a previously-released insect has been redicovered after being presumed to have failed. Rare plant, rare rust but released from its natural enemies BOOM The questiopn we are always asked is how safe is this

25 Is It Safe? Over 1,000 releases of biocontrol agents around the world
>350 agents against 133 target weeds A century of research Any non-target effects are predictable by the vigorous safety testing An International code of conduct 8 examples of “non-target” effects (7 of which predicted or predictable with current approaches) This FAO code of conduct fits in with the CBD and promotes the free and fair exchange of biological control agents

26 EU Activity Country Recipient Source Austria 48 Finland 5 France 111
48 Finland 5 France 111 Germany 46 Greece 29 Italy 71 Portugal 18 Spain 9 Sweden 3 UK 41 Total 381

27 Stenopelmus rufinasus
No stranger to biocontrol

28 Before

29 After

30 Bracken P. aquilinum C. cinsigna tested against 71 spp.
P. angularis tested against 54 spp. C. cinsigna tested against 71 spp.


32 Symptoms of the Fungal Pathogen Phloeospora heraclei
Giant Hogweed (Heracleum mantegazzianum) Parsnip (Pastinaca sativa)

33 This is a typical shot of the unruly knotweed ignoring the rules of the road

34 the bombs we can deal with”
“The site is a challenge. We have identified unexploded wartime bombs and Japanese knotweed……….. the bombs we can deal with” Head of London Development Agency on the subject of the 2012 Olympic site This is the kind of site where the costs can go through the roof. The worst case scenario is £46,000 for a 1m patch on a development site. The 2012 Olympic site has a 4 hectare infestation which has been reported to be costing 65 million to remove. Indeed the london Development Agency Representative is quoted as saying we have problems with unexploded wartime ordinance and Japanese knotweed……….the ordinance we can deal with.

35 Japanese knotweed(s) Fallopia japonica var. japonica Bailey
syn. Reynoutria japonica Houttuyn syn. Polygonum cuspidatum Siebold & Zucc. F. sachalinensis (Giant knotweed) F. x bohemica (hybrid) There I more than on ejapanese knotweed and certainly more than one name for each. It is fairly easy to distinguish the giant from the japonica variety but bohemica versus japonica is a little more tricky. The key is to look for hairs on the underside and the base of the largest leaf. Smooth and flat = japonica Hairy and heart shaped = sachalinensis (plus huge) Small hairs and intermediate leaf base = bohemica In the Uk we have one clone leading to one newspaper describing “the biggest female on earth set to destroy rural Britain” Incidentally JK has many common names and recently the Cornish have adopted the name Ladir tir translated from the democratically selected english descriptor Land thief. Courtesy of Japanese kntoweed manual Child & Wade

36 Phase 2 sponsors AAFC BC

37 Very wide range of “Japanese knotweeds” in Japan.
Often hard to tell apart.

38 Often in these habitats it was the only vegetation for miles around as the substrate was very inhospitable. You can imagine that it found the slag heaps of South Wales home from home


40 Many insects feeding on most parts
186 species of phytophagous arthropod recorded from Japanese knotweed in Japan. Remarkably only one generalist root feeder of note

41 Photo – Prof K. Yano

42 Field observations

43 The Japanese team in their temperate glasshouse with stock plants


45 Pathogens

46 Mycosphaerella polygoni-cuspidati
The agent which still holds the most promise however is this leafspot. Highly damaging and ubiquitous found on Kyushu, Honshu and Shikoku islands, from sea level to altitudes of over 1,m. Coinciding with knotweed emergence in late April through to senescence in October/November Based on 1918 published description in Japanese journal. Neotype needed. Thus, M. polygoni-cuspidati has all the characteristics of a hemibiotroph- a prolonged or well-developed, latent or colonization phase, followed by a necrotic phase, and even production of spermogonia within living tissues-and this life cycle is summarized in schematic form Mycosphaerella polygoni-cuspidati Leafspot fungus- so common that it is included in the Flora of Japan

47 Life cycle Microcyclic or reduced life cycle - only functional spores are spermatia and ascospores Primary source of infection is ascospores, no anamorph or macroconidial stage found No ascomata produced in vivo or in vitro despite varied humidity regimes+agar media trials Mycelial infection found to be comparable in lab 40㎛ The lifecycle is complicated. Categorical ID came over a year into the project when microscopic analysis of fruiting structures placed it firmly in the Mycosphaerella species concept. Very slow growing and previous attempts to identify causal agent revealed only faster growing endophytes Based on both field and experimental data, it is concluded that Mycosphaerella polygoni-cuspidati has a microcyclic or reduced life cycle in which the only functional spores are spermatia and ascospores. There is no evidence of a functional macroconidial stage or a true anamorph in the lifecycle Unlike M. brassicicola, however, ascomata have never been observed in inoculated plants (in vivo) or in culture (in vitro), despite testing various recommended humidity regimes and agar media (Snyder 1946), Nelson and Pound 1959), so it cannot be determined if the fungus is homo-or heterothallic. Indeed, in the field, ascomata are uncommon and most of the material collected over the 4-year period was dominated by the spermogonial stage. It could be argued that ascomata develop mainly after leaf fall but there was no evidence of this from a detailed examination of leaf litter collected prior to and during the winter months.

48 Macro/microscopic analysis
F. Conollyana P. maritimum F.japonica 60 plant spp tested (mainly mycelium) no symptoms on F. sachalinensis & F. compacta 21 N. American species tested to some degree – still promising After days on p. maritimum, guard cell reaction with bohemica F x bohemica

49 Insects

50 DISMISSED Endoclyta excrescens
Which was just as happy boring out of plastic containers as it was knotweed roots

51 Allantus luctifer DISMISSED

52 Machiatella itadori DISMISSED

53 Lixus impressiventris



56 DISMISSED Ex F. japonica host
Can rear through on P. hydropiper but produced very small offspring – too few to establish a culture. Only ever seen on Japanese knotweed in Japan even when populations were very high indeed Ex P. hydropiper host

57 Aphalara itadori





62 Two agents have been selected the first, a Psyllid with high potential, small yet damaging in large numbers. HR studies initiated and looking promising-142,000 eggs followed, <1% laid on plants of concern and none developed.

63 Detailed life cycle studies complete
Egg 1st instar 2nd 3rd 4th 5th Complete life cycle Mean  1SE 9.2  0.1 4.8  0.2 3.3  0.2 3.9  0.3 4.5  0.1 7.1  0.3 32.9  0.8 Range 9 - 10 4 - 6 2 - 5 3 - 8 5 - 11

64 Aphalara information Each female produces a mean of 637 eggs ± (±1SE, n = 11). The mean period of production is 37.5 days ± 5.85 days (±1SE, n = 11). Adults live up to 67 days

65 Centrifugal phylogenetic method:
More closely related species more likely to be attacked than more distantly related ones Family Tribe Subtribe Genus Species

66 Test Plant List 90 species and varieties
representatives from 19 families. All naïve Polygonaceae 37 plants natives 23 species introduced to the UK, 3 species native to Europe, 13 ornamental 10 economically important UK species

67 The 78 spp. that did not receive eggs are excluded
Bar chart showing mean egg count on those plants that did receive eggs in multiple choice oviposition tests. (+/- 1SE). Development only successful to the left of red line

68 Aphalara adult survival

69 Extent of nymph development on NT hosts which have received eggs
Request for more information from CSL as part of review of PRA Hand transferred nymphs Higher humidity than before 6 reps x 10 N1 nymphs = 60 individuals Increased survival on knotweed Risk of artificially increased survival on NTs

70 Nymph % survival over time

71 Muehlenbeckia complexa “wire plant”
“Garden thug” (Clement & Forster, 1994) Weed in Australia US team have found same result for northern Ai strain with another congeneric

72 Aphalara summary Still happy in culture in the UK
87 species / varieties used so far, 3 rare spp. to go 145,172 eggs followed, 928 (0.64%) laid on non-targets but no development Nymph transfer development studies and target-absent oviposition studies largely support findings Adult no-choice starvation studies show very restricted range

73 Impact studies Leaf count Increase in height











84 Interaction with herbicide = Significant increase in leaf loss
Change in leaf number two weeks after spraying with sub-lethal dose of systemic herbicide following exposure to four levels of psyllid feeding

85 Interaction with herbicide Reduction in leaf area

86 Japan 2007 Primarily Giant knotweed in Hokkaido and N. Honshu
Collections of northern species for NA screening



89 R2= 0.9328 Dev Rate per day = 0.01921+0.002162 Temp
DD from egg to adult


91 Overwintering studies on Aphalara
Lab showed survival on Bark, at 5 degrees after 8 weeks So can survive with no food at all. Field work – needle in a haystack


93 What next? Wildlife & Countryside application complete for England (Devolved Authorities version in prep.) Pest Risk Analysis complete Contingency and monitoring plan proposed External peer reviewers begun Public consultation Web (3 months) Stakeholder awareness raising (during above) Ministerial decision (last quarter 09?) Release if authorised (April 2010)

94 Impatiens spp. Himalayan balsam (s)

95 And when the plant forms monocultures similar to this one on the river torridge in north deveon, the seed production of the population can equate to a seed rain of seeds per m sq When hb grows in riparian systems seeds become incorporated into the water body carried down stream rivers throughout the uk have acted as major corridors for this species dispersal Although the Seed bank is relatively short lived 18months Synchronous germination large seed bank to achive sufficent biomass to supress performance of other species it has been shown H.balsam HB has been shown to outcompete some of our most vigerous growing native species

96 2007 By the year 2000 hob occurs in over ½ of the 10km recording squares Confidently say few rivers in the Uk which haven't been colonised by hob

97 Native range balsam spans 2 countries
Regional centre, aid travel, communication excellent ecologists and botanists Decided to sample in august when the plant was in full bloom, aid identification and this was the optimum time for plant pathogens why???? Unfortuantly sampling in august was to the detriment of arthopod collections we didn’t collect anything like the number of species we would have hoped for At the time of of the survey collecting in india would have been extremely difficult.


99 Further collections could identify more aggressive strains and different species
CABI has experience working with leaf-spot pathogens (Mycosphaerella-Japanese knotweed) Biocontrol potential: HIGH


101 And some highly promising pathogens especially a rust fungus which seems to hit the seedling and therefore key stage of the target plant

102 Floating pennywort Hydrocotyle ranunculoides
This is a canal! Floating pennywort Hydrocotyle ranunculoides

103 Background Hydrocotyle ranunculoides is a serious invader of water bodies in the UK It is banned in Holland and a recent addition to the EPPO alert list 50km stretch was identified in Leicestershire canal Control is extremely difficult and the plant is still spreading

104 There are a lot of aquatic plants in Argentina


106 And less scary species

107 We found pathogens and ….

108 Listronotus elongatus
The achile’s heel for aquatic weeds……….a weevil Listronotus elongatus

109 Highly damaging in the field and in the lab

110 Though we nearly lost the culture to Beavaria, we managed to establish enough to carry out feeding, egg laying and development tests

111 Multi choice 50 adults Heavy damage and egg laying on target, only trace feeding on native

112 EU opportunities Sheppard, Shaw & Sforza - Weed Research 2006
Species Form Origin EU distribution Genus native? Conflict BC history Buddleja davidii Ph China Temperate Nob O Yes Fallopia japonica Ge Japan No Acacia dealbata Australia Mediterranean Yesd Azolla filiculoides Hy N America Temp/Med Ailanthus altissima Impatiens glandulifera He India Rhododendron ponticum S Europe Robinia pseudoacacia F Senecio inaequidens S Africa Ambrosia artemisiifolia Th C America Carpobrotus edulis Ch Heracleum mantegazzianum W Asia Solanum elaeagnifolium S America Tem/Med Baccharis halimifolia Hydrocotyle ranunculoides Ludwigia peploides Crassula helmsii Australasia Elodea canadensis Myriophyllum aquaticum Solidago canadensis

113 Thank you Shaw, R.H., Bryner, S. & Tanner, R. (2009). The life history and host range of the Japanese knotweed psyllid, Aphalara itadori Shinji: potentially the first classical biological weed control agent for Europe. Biological Control 49: Kurose, D., Evans, H.C., Djeddour, D.H., Canon, P.F., Furuya, N. & Tsuchiya, K. (2009) Mycosphaerella species as potential biological control agents of the invasive weed Fallopia japonica. Mycoscience (in press) Sheppard, A.W., Shaw, R.H. & Sforza, R. (2006) Classical biological control of European exotic environmental weeds: The top 20 potential targets and the constraints. Weed Research 46 pp93-118

114 Himalayan knotweed Rapidly spreading in UK and N. America and very hard to control. Recent surveys in Pakistan revealed very promising agents……

115 Unidentified weevil and rust on Himalayan knotweed in Pakistan

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