The Natural Host Range of Beetle Species Feeding on Broom, Cytisus scoparius (L.) Link (Fabaceae), in Southwest Europe

The natural host range of beetles feeding on broom ( Cytisus scoparius ) and 14 other species (including six other Cytisus species) in the tribe Genisteae was investigated at 39 sites in Spain , Portugal and France in 1989 and 1992 as part of a biological control programme for broom . Data on host - plant associations were analyzed for 36 phytophagous beetle species from 18 sites , and host records were listed for an additional 58 species . Nine species were apparently restricted to the genus Cytisus : Cryptocephalus octoguttatus, Gonioctena olivacea, Bruchidius lividimanus, B. villosus, Exapion elongatissimum, E. fuscirostre, Lepidapion sp . 1 , Polydrusus confluens and Tychius parallelus. These field records suggest a narrower host - plant range for some beetle species than laboratory host - range tests , and may assist in interpreting host - plant associations reported in the literature . Beetle species with a restricted host - plant range were rarely found on related non - host plants .     

The Effect of Variability in the Phenology of the Reproductive Stages of Scotch Broom (Cytisus scoparius) on the Synchronization of the Life Stages of Broom Seed Beetle (Bruchidius villosus) in New Zealand

Variability in timing of the reproductive stages of Scotch broom (Cytisus scoparius) may influence synchronization and establishment of the broom seed beetle (Bruchidius villosus), a biological control agent. A sampling scheme was devised to compare the phenologies of Scotch broom at different sites in the same season and in different seasons at the same site. The synchrony of the broom seed beetle's life stages with those of the host plant was also determined. The phenology of Scotch broom varied only slightly from season to season at Lincoln, but could vary considerably between sites in the same season. At both sites where it is established, the broom seed beetle was synchronized with its host; adult beetles were present throughout the flowering period. Eggs were found on suitable green pods. The broom seed beetle appears capable of adapting to the phenology of its host and has the potential to be an effective agent for Scotch broom. Variability in phenology of the reproductive stages of Scotch broom, even at nearby sites, must be taken into account by practitioners of biological control when releasing broom seed beetles and later when sampling beetles to determine establishment.     

Implications of individual variation in insect behavior for host specificity testing in weed biocontrol

This study shows that individual behavioral variation is an under-recognised source of error that may affect the outcome of host range tests in a stenophagous species. Original specificity testing of the broom seed beetle, Bruchidius villosus (F.) (Coleoptera: Chrysomelidae: Bruchinae), a biocontrol agent for Scotch broom, Cytisus scoparius (L.) Link (Fabaceae: Genisteae), failed to detect its ability to oviposit in the field on a congeneric non-target plant, the exotic Cytisus proliferus L.f. (Fabaceae: Genisteae). These tests were repeated using individual beetles from the original UK collection sites and from New Zealand, 15 generations post release. In the original tests, low replication of small batches of females masked high levels of individual variation in oviposition preference. Although most beetles showed strong preference for the target weed, there was some indication that New Zealand beetles showed higher preference for the non-target than UK beetles.     

Gallerucida bifasciata (Coleoptera: Chrysomelidae), a potential biological control agent for Japanese knotweed (Fallopia japonica)

Host specificity of foreign natural enemies are becoming more and more critical in classical biological control programs, as concerns about potential risk from introduced biocontrol agents have been increasing recently. Understanding the insect's fundamental and ecological host ranges is the first step in determining the potential for introduction of an insect to control invasive plants. Japanese knotweed, Fallopia japonica (Houttuyn) Ronse Decraene (Polygonaceae) is an invasive weed in the United States and Europe. A leaf beetle, Gallerucida bifasciata (Coleoptera: Chrysomelidae) is an important natural enemy attacking this plant in Asia. However, its host range records were ambiguous. This study examined the beetle's host specificity through a set of choice and no-choice tests in the laboratory and field in its native China. Gallerucida bifasciata larvae were able to complete development on seven of 87 plant species in larval development tests, while adults fed and oviposited on 10 plants in no-choice tests. Multiple choice tests showed adults strongly preferred Fallopia japonica, Persicaria perfoliata (L.) H. Gross and Polygonum multiflorum Thunb over all other plants. Open field tests and field surveys further revealed that these three species were in its ecological host range. The results of this study suggest that G. bifasciata is a potential promising agent for control of Japanese knotweed in the United States and Europe, although additional host specificity tests and risk assessment should be completed.     

Avoiding conflicts between insect and weed biological control: selection of non-target species to assess host specificity of cabbage seedpod weevil parasitoids

Abstract:  Classical biological control of insect pests and weeds may lead to potential conflicts, where insect pests are closely related to weed biological control agents. Such a conflict may occur in the classical biological control of the cabbage seedpod weevil, Ceutorhynchus obstrictus (Marsham) in North America, which belongs to the same subfamily, Ceutorhynchinae, as a number of agents introduced or proposed for introduction against non-indigenous invasive weed species. We propose a step-by-step procedure to select non-target species and thereby to develop a non-target species test list for screening candidate entomophagous biological control agents of a herbivore pest insect in a way that would simultaneously evaluate non-target potential on weed biological control agents and other non-target species. Using these recommendations, we developed a non-target test list for host specificity evaluations in the area of origin (Europe) and the area of introduction (North America) for cabbage seedpod weevil parasitoids. Scientifically based predictions on expected host–parasitoid interactions and ecological information about the ecological host range in the area of origin can help avoid conflicts, while still allowing the introduction of safe and effective agents against both insect pests and weeds.     

Biology and host specificity of Aulacobaris fallax (Coleoptera: Curculionidae), a potential biological control agent for dyer’s woad,Isatis tinctoria (Brassicaceae) in North America

Dyer’s woad, Isatis tinctoria, a plant of Eurasian origin is a problematic weed in western North America against which a classical biological weed control programme was initiated in 2004. Three European insect species were selected as candidate agents to control this invasive species, including the root‐mining weevil Aulacobaris fallax. To determine its suitability as an agent, the biology and host specificity of A. fallax were studied in outdoor plots and in the field between 2004 and 2006 in its native European range. Aulacobaris fallax is a univoltine species that lays its eggs from March to August into leaf stalks and roots of dyer’s woad. Larvae mine and pupate in the roots and adults emerge from August to October. Up to 62% of the dyer’s woad plants at the field sites investigated were attacked by this weevil. In no‐choice host‐specificity tests, A. fallax attacked 16 out of 39 species and varieties within the Family Brassicaceae. Twelve of these are native to North America. In subsequent multiple‐choice tests, seven species, all native to North America, suffered a similar level of attack as dyer’s woad, while none of the European species were attacked. Our results demonstrate the importance of including test plant species that have not co‐evolved with the respective candidate agent. In sum, we conclude that the risk of non‐target effects is too high for A. fallax to be considered as a biological control agent for dyer’s woad in the United States.     

Potential novel hosts for the lily leaf beetle Lilioceris lilii Scopoli (Coleoptera: Chrysomelidae) in eastern North America

Abstract.  1. Introduced insects often incorporate native plants into their diets and might be expected to show a predilection for novel hosts that are phylogenetically related to their normal hosts. The lily leaf beetle, Lilioceris lilii (Coleoptera: Chrysomelidae), is an introduced pest of cultivated lilies. Oviposition behaviour, larval behaviour, and development of L. lilii was examined on a range of potential host plants, as well as on the normal host, Asiatic hybrid lilies Lilium sp.
2. Neonate larval feeding behaviour was quantified on 15 food plant species: 10 from the Liliales, three from the Asparagales and two eudicots. Larvae fed plants closely related to the genus Lilium were more likely to initiate feeding, less likely to abandon their food leaf, and consumed more leaf area.
3. In no-choice tests, females oviposited on the novel hosts Lilium philadelphicum , Medeola virginiana , Clintonia borealis , Streptopus amplexifolius , and Polygonatum biflorum ; however, all but L. philadelphicum received very few eggs. Non- Lilium novel hosts were not used for oviposition when presented along with Asiatic lilies in choice tests.
4. A single individual was reared to the adult stage on the novel host S. amplexifolius . Several larvae survived to the pupal stage on M. virginiana , although no adults emerged from those pupae. Larvae reared on the native wood lily L. philadelphicum performed equally well or better than on the Asiatic cultivar.
5. Our results indicate that the lily leaf beetle poses a threat to native Liliaceae. Several native Lilium species, including L. philadelphicum , are threatened or endangered in certain jurisdictions throughout their range; these species should be monitored closely for colonisation by the beetle.     

Scientific advances in the analysis of direct risks of weed biological control agents to nontarget plants

Research on host specificity testing protocols over the last 10 years has been considerable. Traditional experimental designs have been refined and interpretation of the results is benefiting from an improved understanding of agent behavior. The strengths, weaknesses, and best practice for the different test types are now quite clearly understood. Understanding the concept of fundamental host range (the genetically determined limits to preference and performance) and using this to maximize reliability in predicting field host specificity following release (behavioral expression of the fundamental host range under particular conditions) are still inconsistently understood or adopted despite having been identified as the critical steps in analyzing the threats posed by biological control agents to the agriculture and biodiversity of novel environments. This needs to be consistently understood and applied so the process of testing can follow a recognized process of risk analysis from hazard identification (identifying life stages of the agent that pose a threat and defining their fundamental host range) to uncertainty analysis based on the magnitude (predicted field host specificity following release) and likelihood of threats (predicted actual damage and impact) to nontargets. Modern molecular techniques are answering questions associated with subspecific variation in biological control agents with respect to host use and the chance of host shifts of agents following release. Guidelines for assessment of nontarget impacts need to recognize and adopt such recent developments and emphasize a general increased understanding of the evolution of host choice and the phylogenetic constraints to shifts in host use. This review covers all these recent advances for the first time in one document, highlighting how inconsistent interpretation by biological control practitioners can be avoided.     

Cryptic species of a water hyacinth biological control agent revealed in South Africa: host specificity,impact, and thermal tolerance

The discovery that cryptic species are more abundant than previously thought has implications for weed biological control, as there is a risk that cryptic species may be inadvertently released with consequences for the safety of the practice. A cryptic species of a biological control agent released for the control of the invasive alien macrophyte, water hyacinth, Eichhornia crassipes (C. Mart.) Solms. (Pontederiaceae), was recently discovered in South Africa. The two species were considered a single species prior to genetic analysis and interbreeding experiments. The original biological control agent retains the name Eccritotarsus catarinensis (Carvalho) (Heteroptera: Miridae) whereas the new species has been described as Eccritotarsus eichhorniae Henry. In this study, we compared the host specificity, efficacy, and thermal physiologies of the two species. The host specificity of the two species within the Pontederiaceae was very similar and both are safe for release in South Africa. Comparison of the per capita impact of the two species indicated that E. eichhorniae was the more damaging species but this is likely to be influenced by temperature, with E. catarinensis being more effective under lower temperatures and E. eichhorniae being more effective under higher temperatures. Releasing the correct species for the thermal environment of each release site will improve the level of control of water hyacinth in South Africa. This example highlights the need to keep populations of biological control agents from different native range collection localities separate, and to screen for host specificity and efficacy.     

Post-establishment assessment of host plant specificity of Arytainilla spartiophila (Hemiptera: Psyllidae), an adventive biological control agent of Scotch broom,Cytisus scoparius

Scotch broom, Cytisus scoparius (Fabaceae), is a shrub native to Europe that is invasive in the USA, New Zealand and Australia. The psyllid Arytainilla spartiophila has been purposely introduced to Australia and New Zealand as a biological control agent of C. scoparius, but is an accidental introduction to California. Lupines (Lupinus spp.) are the closest native taxon to Cytisus in North America, and are therefore considered to be at the highest risk for non-target damage. However, because no lupines are native to Australia or New Zealand, only one imported forage species was evaluated during prior host specificity testing. We conducted a laboratory nymphal transfer experiment, a field choice experiment and a field survey to assess risk to three lupine species (Lupinus albifrons, Lupinus bicolor and Lupinus formosus). In the laboratory, 20% of third-instar nymphs were able to develop to adulthood on L. formosus but not on the other lupine species, while 40% completed development on C. scoparius. In the field experiment, potted lupine and C. scoparius plants were placed beside large infested C. scoparius plants; oviposition occurred on all the potted C. scoparius plants, but on none of the lupines. In the field survey, no A. spartiophila eggs or nymphs were found on naturally occurring lupines growing adjacent to infested C. scoparius. The results indicate that A. spartiophila is not likely to damage or reproduce on lupines in the field. This study provides an example of how field studies can help clarify the host specificity of biological control agents.     

Prioritisation of potential agents for the biological control of the invasive alien weed,Pereskia aculeata (Cactaceae), in South Africa

Pereskia aculeata Miller (Cactaceae) is an invasive alien species in South Africa that is native in Central and South America. In South Africa, P. aculeata outcompetes native plant species leading to a reduction in biodiversity at infested sites. Herbicidal and mechanical control of the plant is ineffective and unsustainable, so biological control is considered the only potential solution. Climatic matching and genotype matching indicated that the most appropriate regions in which to collect biological control agents were Santa Catarina and Rio de Janeiro provinces in Southern Brazil. Surveys throughout the native distribution resulted in 15 natural enemy species that were associated with the plant. Field host range data, as well as previous host plant records, were used to prioritise which of the species were most likely to be suitably host specific for release in South Africa. The mode of damage was used to determine which species were most likely to be damaging and effective if released. The most promising species prioritised for further study, including host specificity and impact studies, were the stem-wilter Catorhintha schaffneri Brailovsky & Garcia (Coreidae); the stem boring species Acanthodoxus machacalis Martins & Monné (Cerambycidae), Cryptorhynchus sp. (Curculionidae) and Maracayia chlorisalis (Walker) (Crambidae) and the fruit galler Asphondylia sp. (Cecidomyiidae). By prioritising the potential biological control agents that are most likely to be host-specific and damaging, the risk of conducting host specificity testing on unsuitable or ineffective biological control agents is reduced.     

Ecological role of control agent,and not just host‐specificity,determine risks of biological control

Biological control agents used to manage alien vegetation are generally viewed as providing an ecosystem service, owing to reduced ecological and economic costs of invasion following their release. In particular, gall‐formers are popular as biological control agents because they are host‐specific and therefore considered low risk. However, galls can also be considered to be ecological engineers, because they provide nutritional resources for native invertebrates. We tested whether native invertebrates had formed associations with the gall‐forming fungus Uromycladium tepperianum, introduced into South Africa to control the Australian invasive alien tree Acacia saligna, by collecting U. tepperianum galls and monitoring emergence. We found that a number of invertebrates had formed associations with the biological control agent, among which was the important citrus pest, Thaumatotibia leucotreta (false codling moth). We used pheromone‐baited traps to ascertain if this supplementary source of T. leucotreta increased their abundance in orchards close to patches of gall host, but did not find this to be the case. We did find, however, that control measures used by farmers explained T. leucotreta abundances in traps, which may have obscured detection of any effects of a nearby host for the pest. Nevertheless, this study illustrates the first case of a host‐specific classical biological control agent providing resources for an economically significant crop pest. We conclude that although biological control agents are strictly vetted to ensure host‐specificity, introduced biological control agents that become abundant and can act as ecological engineers pose risks when native biota form associations with them, resulting in a number of possible cascading ecosystem effects. In addition, there could be economic consequences when these associated species include agricultural pests. We conclude that not just host specificity, but potential ecological effects of biological control agents, should be considered in their selection.     

Pollinators exert positive selection on flower size on urban,but not on rural Scotch broom (Cytisus scoparius L. Link)

Aims Adaptive evolution of invasive species is both particularly exciting for the evolutionary biologist and worrisome for those interested in controlling or halting spread. Invasive species often have a distinct timeline and well-recorded population expansion. As invaders encounter new environments, they undergo rapid adaptive evolution. Our aim in this study was to measure variation of floral size in the invasive shrub Cytisus scoparius (Scotch broom) and measure natural selection by pollinators on that trait. Past research has found that this invasive plant is pollinator limited in Washington State and that declines in pollinator populations can contribute to local extinction in another invaded range (New Zealand). This plant is pollinated by both native and introduced species of bees, representing a broad range of pollinator sizes. Cytisus scoparius has a flower structure that is highly conducive to studies on pollinator choice, even in the absence of direct pollinator observations.Methods We surveyed urban and rural sites in and around the city of Olympia in Washington State. Measuring banner width, we were able to show that flower size varies substantially between plants but minimally within plants. By measuring the proportion of flowers that were 'tripped', we could determine pollinator visitation rates and thus determine the level of selection due to pollinator choice alone.Important findings We found that C. scoparius is under natural selection by pollinators for increased flower size. However, such positive natural selection was only seen in urban populations although it was consistent across two flowering seasons. Rural populations of Scotch broom do not appear to be under selection on flower size. The natural selection by pollinators on broom flowers could result in adaptive evolution into a new pollination niche by an invading species. A higher level of variation in broom flowers seen here than seen in previous works in native regions suggests that C. scoparius may be highly diverse and primed for adaptive evolution.     

Biology and host range of Mada polluta,a potential biological control agent of Tecoma stans in South Africa

The host range of Mada polluta Mulsant (Coleoptera:Coccinnellidae) was studied to assess its suitability as a biological control agent of Tecoma stans (L.) Juss ex Kunth var stans (Bignoniaceae), an invasive weed in South Africa. Biology of M. polluta and its host range were determined in the laboratory using no-choice and multi-choice feeding, oviposition and larval survival tests. Out of 36 plant species from 12 plant families (Bignoniaceae, Acanthaceae, Asteraceae, Verbenaceae, Lamiaceae, Oleaceae, Cucurbitaceae, Fabaceae, Scrophulariaceae, Solanaceae, Apiaceae, Chenopodiaceae and Poaceae) within the order Lamiales that were tested during the host specificity testing, M. polluta showed a very strong preference for T. stans, depositing its eggs on T. stans and none on non-target plant species. In no-choice tests, an average of 246 eggs was laid on T. stans, and from these, 133 larvae developed to adulthood. The beetle also showed very promising biological attributes that will contribute to its success as a biological control agent of T. stans. These attributes include highly damaging larvae and adults, high fecundity (532 eggs/female) and a short life cycle (four weeks). The short life cycle will enable multiple generations per year and rapid population increase in the field. It is concluded that M. polluta is sufficiently host-specific to be released against T. stans in South Africa. It is, therefore, strongly recommended that permission be granted to release this beetle from quarantine for biological control of T. stans in South Africa.     

Predicting the host range of Nystalea ebalea: Secondary plant chemistry and host selection by a surrogate biological control agent of Schinus terebinthifolia

The safety of weed biological control depends upon the selection and utilization of the target weed by the agent while causing minimal harm to non-target species. Selection of weed species by biological control agents is determined by the presence of behavioral cues, generally host secondary plant compounds that elicit oviposition and feeding responses. Non-target species that possess the same behavioral cues as found in the target weed may be at risk of damage by classical biological control agents. Here we conducted host range tests and examined secondary plant compounds of several test plant species. We studied the specialist herbivore Nystalea ebalea (Lepidoptera: Notodontidae) a Neotropical species, present in Florida as a surrogate biological control agent of the weed, Brazilian peppertree Schinus terebinthifolia, invasive in Florida and Hawaii. We found that the larvae had the greatest survival when fed the target weed, the Neotropical species Spondias purpurea, the Florida native species Rhus copallinum, and the ornamental Pistacia chinensis. Reduced survival and general larval performance were found on the native species Metopium toxiferum and Toxicodendron radicans. Both the volatiles and the allergen urushiols were chemically characterized for all species but urushiol diversity and concentration best predicted host range of this herbivore species. These results provide insight into host selection and utilization by one oligophagous Schinus herbivore. Other potential biological control agents may also be sensitive to plants that contain urushiols and if so, they may pose minimal risk to these native species.     

Grasses as appropriate targets in weed biocontrol: is the common reed, <Emphasis Type="Italic">Phragmites australis</Emphasis>, an anomaly?

Despite their importance as invasive species, there has been a hesitation to target grasses in classical biocontrol. This historic bias appears to be changing with multiple active research and release programs. Similarly, biocontrol workers appear to avoid targeting species with native congeners. These biases appear inappropriate as the ecological and entomological literature provide abundant evidence for sub-genus specificity for many herbivores, including those attacking grasses. The biocontrol program targeting Phragmites australis (Cav.) Trin. ex Steud (Poaceae) provides an informative example with endemic subspecies in North America and many sub-genus specific herbivores, including potential European control agents. Grasses and target weeds with congeneric native species require rigorous host range testing, similar to all other targets in current weed biological control programs. Furthermore, it appears prudent to ask petition reviewers and regulatory agencies to abandon their focus on results of no-choice studies and to distinguish between trivial feeding and demographic impacts.     

Biological control of Rhamnus cathartica: is it feasible? A review of work done in 2002–2012

Rhamnus cathartica (common buckthorn) is a shrub (or small tree) of Eurasian origin, which has become invasive in North America. Internal feeders and sap suckers were prioritized for biological control from over 30 specialized insects identified from the target plant in its native European range. Five leaf‐feeding moths were also considered for further investigations. Field observations and preliminary host range tests with the stem‐boring beetle Oberea pedemontana, the root‐boring moth Synanthedon stomoxiformis, the shoot‐tip‐boring moth Sorhagenia janiszewskae and the leaf‐feeding moths Ancylis apicella, A. unculana, Triphosa dubitata, Philereme transversata and P. vetulata confirmed that all of these species were lacking host specificity in no‐choice conditions. Choice oviposition tests carried out with most of the prioritized species to assess their ecological host range yielded unreliable results. Three psyllids, Trichochermes walkeri, Cacopsylla rhamnicolla and Trioza rhamni are promising in terms of host specificity, but are infected with the plant disease ‘Candidatus Phytoplasma rhamni’. Fruit‐ or seed‐feeding insects may present the best potential for biological control of buckthorn in directly reducing seed set and thus seedling establishment. However, it was not possible to obtain adult fruiting trees of native North American Rhamnus species for testing. It is concluded that there are no promising arthropod agents based on what is known to date. Pathogens could offer new opportunities for biological control of R. cathartica in North America.     

Observations on the host specificity and biology of Lixus salsolae (Col., Curculionidae), a potential biological control agent of Russian thistle, Salsola tragus (Chenopodiaceae) in North America

Abstract:  No-choice host specificity tests were performed on Lixus salsolae Becker (Col., Curculionidae) in a quarantine green house near Montpellier, France. Several varieties of seven species of economic and ornamental plants from six genera of Chenopodiaceae were tested. Adult feeding was observed on almost all test plants and larvae successfully developed on nine of the eleven species/varieties tested. Sex ratio of field-collected overwintering adults was close to 1 : 1. While no-choice tests may indicate a wider host range under field conditions, we no longer consider L. salsolae as a potential biological control agent of Salsola tragus L. (Chenopodiaceae) in North America.     

Statistical tools to interpret risks that arise from rare events in host specificity testing

Host specificity testing to predict host range is one of the key steps to predicting the risk a biological control agent will present to non-target organisms in the new environment. When host specificity testing data contain discrepancies, or unacceptable levels of uncertainty, it can be difficult for decision-makers to adequately address this uncertainty. To better understand the uncertainty in host specificity testing, we used a range of statistical tools to examine a data set associated with the leaf weevil Cleopus japonicus (Curculionidae), a biological control agent for the weed Buddleja davidii (Buddlejaceae) in New Zealand. Significant uncertainty arose during the early stages of host specificity testing when one C. japonicus larva reared to pupation on a culturally important native plant. Further trials were conducted to evaluate the suitability of C. japonicus as a biological control agent, and despite the uncertainty, C. japonicus was released in New Zealand in 2006, and has since established populations at each release site. However, the possibility of larvae completing their life cycle on the native plant initiated this evaluation of the statistics associated with testing biological control agents. We present results from analyses of the C. japonicus survival data using confidence intervals, equivalence testing, power analyses and survival curves to highlight the appropriateness of each of these tools for interpreting host specificity tests in biological control.     

Biological control of Ziziphus mauritiana (Rhamnaceae): feasibility,prospective agents and research gaps

The tropical fruit tree, Ziziphus mauritiana (Rhamnaceae), a native of the Indian subcontinent, is a pasture and environmental weed in northern Australia and Fiji. In their native range, Ziziphus spp., including commercially cultivated Z. mauritiana and Z. jujuba, are subjected to a wide range of pests and diseases. The feasibility of classical biological control of this weed has not been explored to date. Effective biological control could reduce plant vigour and seed output, thereby limiting the spread of Z. mauritiana in Australia. Two Ziziphus species are native to Australia, hence, any prospective biological control agent should be specific to Z. mauritiana. Opportunistic field surveys and literature searches identified 133 species of phytophagous insects, 9 species of phytophagous mites and 12 plant pathogens on Ziziphus spp. Host records suggest the following are possibly specific to Z. mauritiana and hence are prospective biological control agents in Australia: the seed‐feeding weevil Aubeus himalayanus; the leaf‐feeding gracillariid moth Phyllonorycter iochrysis; the leaf‐mining chrysomelid beetle Platypria erinaceus; the leaf‐folding crambid moth Synclera univocalis; the leaf‐galling midge Phyllodiplosis jujubae; and the gall‐mites Aceria cernuus and Larvacarus transitans. Host range of the rust Phakopsora zizyphi‐vulgaris includes many Ziziphus species, including the native Z. oenoplia and hence would not be a suitable biological control agent in Australia. The powdery mildew Pseudoidium ziziphi, with a host range restricted to Ziziphus species, has not been reported on Z. oenoplia. All available information on the pests and diseases of Z. mauritiana are from cultivated varieties. Hence, future surveys should focus on wild Z. mauritiana in the Indian subcontinent in areas that are climatically similar to the regions of northern Australia, where it is currently most abundant.