Assessing the risks of releasing a sap-sucking lace bug, <Emphasis Type="Italic">Gargaphia decoris</Emphasis>, against the invasive tree <Emphasis Type="Italic">Solanum mauritianum</Emphasis> in New Zealand

The South American tree Solanum mauritianum Scopoli (Solanaceae), a major environmental weed in South Africa and New Zealand, has been targeted for biological control, with releases of agents restricted to South Africa. The leaf-sucking lace bug, Gargaphia decoris Drake (Tingidae), so far the only agent released, has become established in South Africa with recent reports of severe damage at a few field sites. To evaluate the insect’s suitability for release in New Zealand, host-specificity testing was carried out in South Africa in laboratory and open-field trials, with selected cultivated and native species of Solanum from New Zealand. No-choice tests confirmed the results of earlier trials that none of the three native New Zealand Solanum species are acceptable as hosts. Although the cultivated Solanum muricatum Aiton and S. quitoense Lam. also proved unacceptable as hosts, some cultivars of S. melongena L. (eggplant) supported feeding, development and oviposition in the no-choice tests. Although eggplant was routinely accepted under laboratory no-choice conditions in this and previous studies, observations in the native and introduced range of G. decoris, open-field trials and risk assessment based on multiple measures of insect performance indicate that the insect has a host range restricted to S. mauritianum. These results strongly support the proposed release of G. decoris in New Zealand because risks to non-target native and cultivated Solanum species appear to be negligible. An application for permission to release G. decoris in New Zealand will be submitted to the regulatory authority. Handling editor: John Scott.     

Assessing the risks associated with the release of a flowerbud weevil, Anthonomus santacruzi, against the invasive tree Solanum mauritianum in South Africa

Biological control of Solanum mauritianum Scopoli, a major environmental weed in the high-rainfall regions of South Africa, is dependent on the establishment of agents that can reduce fruiting and limit seed dispersal. The flowerbud weevil, Anthonomus santacruzi Hustache, is a promising fruit-reducing agent, despite ambiguous results obtained during host-specificity evaluations in quarantine. Adult no-choice tests showed that although feeding is confined to Solanum species, normal feeding and survival occurred on the foliage (devoid of floral material) of cultivated eggplant (aubergine), potato, and several native South African Solanum species. During paired-choice tests, involving floral bouquets in 10-liter containers, A. santacruzi oviposited in the flower buds of 12 of the 17 test species, including potato and eggplant, although significantly more larvae were recovered on S. mauritianum than on eight other species. Larvae survived to adults on all 12 species, with survival significantly lower on only four species than on S. mauritianum. However, during multi-choice tests, involving potted plants in a large walk-in cage, A. santacruzi consistently displayed significant feeding and oviposition preferences for S. mauritianum over all of the 14 Solanum species tested. Analyses of the risk of attack on nontarget Solanum plants suggested that, with the possible exception of two native species, none is likely to be extensively utilized as a host in the field. Also, host records and field surveys in South America have suggested that A. santacruzi has a very narrow host range and that the ambiguous laboratory results are further examples of artificially expanded host ranges. These and other considerations suggest that A. santacruzi should be considered for release against S. mauritianum in South Africa, and an application for permission to release the weevil was submitted in 2003.     

Biology, host specificity and risk assessment ofGargaphia decoris, the first agent to bereleased in South Africa for the biological control ofthe invasive tree Solanum mauritianum

The South American tree Solanummauritianum is a major environmental weed in thehigh-rainfall regions of South Africa and has beentargeted for biological control since 1984. Althoughhost ranges of imported agents determined duringquarantine tests have resulted in the rejection ofeight of the 11 candidate agents tested so far, theleaf-sucking lace bug Gargaphia decoris,imported from Argentina in 1995, displayed anacceptably narrow host range in captivity. No-choicetests showed that G. decoris is confined to Solanum species and cannot survive on solanaceouscrops outside that genus. Although these tests alsoindicated that G. decoris colonies could surviveand reproduce on cultivated eggplant (aubergine) andat least five native South African Solanumspecies, all but one native species proved to beinferior hosts in terms of adult survival andoviposition potential. During paired choice andmultichoice tests in small and larger cagesrespectively, G. decoris displayed very strongfeeding and oviposition preferences for S. mauritianum. Analyses of the risk of attack onnon-target Solanum plants revealed that, withone possible exception, none were likely to suffermore than incidental damage in the field. Host recordsfrom South America have also indicated that G. decoris has not been recorded on any Solanumspecies other than S. mauritianum, providingfurther evidence of its host specificity. The resultsof this study were accepted by the regulatoryauthorities and in February 1999, G. decorisbecame the first agent to be released in South Africafor the biological control of S. mauritianum.     

Should the flower bud weevil Anthonomus santacruzi (Coleoptera: Curculionidae) be considered for release against the invasive tree Solanum mauritianum (Solanaceae) in New Zealand?

The invasive tree Solanum mauritianum Scop. has been targeted for biological control in South Africa and New Zealand, by deploying insect agents that could constrain its excessive reproductive output. The flower-feeding weevil Anthonomus santacruzi (Curculionidae) was approved for release in South Africa in 2007 but following the loss of the original culture in quarantine, new stocks were introduced from Argentina in 2008–2009. This study was initiated to confirm that the host range of the new culture was the same as that of the previous one, but also to assess the risks associated with the weevil's release in New Zealand. Different testing procedures, including no-choice tests and multi-choice tests in different arenas, produced inconsistent and ambiguous results. During no-choice tests, oviposition and larval development to adulthood occurred on three non-target species including two native South African and one native New Zealand Solanum species. However, subsequent multi-choice tests and a risk assessment suggested that the risks of anything more than collateral damage to non-target Solanum species are low. Overall, these data do not deviate substantially from the results of the original quarantine tests which facilitated the release of A. santacruzi in South Africa in 2009. Although we argue that none of the New Zealand native and cultivated species are at risk, stronger evidence from open-field trials and chemical ecology studies may be required to convince the regulatory authorities that A. santacruzi is suitable for release in New Zealand.     

Biological control of <Emphasis Type="Italic">Lantana camara</Emphasis> in South Africa: targeting a different niche with a root-feeding agent, <Emphasis Type="Italic">Longitarsus</Emphasis> sp.

The root-feeding flea beetle, Longitarsus sp. (Coleoptera: Chrysomelidae: Alticinae), was studied as a potential biological control agent for Lantana camara L. (Verbenaceae) in South Africa. Host range tests were carried out on 52 plant species in 11 families. Although 11 plant species, all in the family Verbenaceae, supported complete development of Longitarsus sp. during no-choice tests, the beetles showed very strong preferences for L. camara during paired-choice and multi-choice tests. The results confirm that the beetles have a narrow host range, and that under natural conditions they are highly unlikely to utilise plants other than L. camara. In the unlikely event that some of the Lippia spp. are attacked in the field, they are not expected to sustain populations of the flea beetle over time. Attributes that should enhance the biocontrol potential of Longitarsus sp. include: the adults are long-lived and highly mobile; and, the larvae cause extensive direct damage to the roots of L. camara, which could in turn expose the plants to soil-born pathogens. All indications are that Longitarsus sp. could make a substantial contribution to the biological control of L. camara in many countries around the world because the beetles pose no threat to non-target plant species and they damage a part of the plant (i.e. roots) not yet affected by any other agent species.     

Biology and host range of Platyphora semiviridis, a leaf beetle evaluated as a potential biological control agent for Solanum mauritianum in South Africa

The South American tree Solanum mauritianum is a major environmental weed in the high-rainfall regions of South Africa and has been targeted for biological control. Potential agents included five species of the genus Platyphora, which were imported from South America in 1994. Platyphora species associated with Solanaceae reputedly have very specific habitat requirements and host plant preferences in the field. Despite this, host-specificity tests on one species, Platyphora semiviridis, revealed a broad physiological host range. Although laboratory tests showed that P. semiviridis is confined to Solanum species and cannot survive on solanaceous crops outside that genus, it developed on potato and cultivated eggplant (aubergine) as well as on 10 native South African Solanum species. With few exceptions, there were no consistent differences in survival and duration of development on these compared with S. mauritianum. Furthermore, at least six of these non-target species, including potato and eggplant, supported breeding colonies of the beetles in cages. During choice tests in both small and larger cages, P. semiviridis avoided potato but did not consistently discriminate between S. mauritianum, eggplant and six native solanums for larviposition. Despite these findings, P. semiviridis has never been recorded on either potato or eggplant in South America, where it was only observed to feed on S. mauritianum. Although there are several reasons why P. semiviridis is unlikely to attack non-target Solanum species in the field, it will not be released in South Africa because there are other imported agents which have displayed narrower physiological host ranges and which may be more effective.     

Host specificity of Metriona elatior, a potential biological control agent of tropical soda apple, Solanum viarum, in the USA

The leaf beetle Metriona elatior from Brazil-Argentina was screened in the Florida (USA)State quarantine facility as a potential biological control agent of tropical soda apple, Solanum viarum, a recently arrived weed species. Multiple-choice host-specificity tests were conducted in small cages (60 cm × 60 cm × 60 cm) using 95 plant species in 29 families. Adults fed heavily on the main target weed (S. viarum), and on turkey berry,Solanum torvum (noxious weed of Asiatic origin); fed moderately on red soda apple, Solanum capsicoides (weed of South American origin), and eggplant, Solanum melongena (economic crop); and fed lightly on aquatic soda apple, Solanum tampicense (weed of Mexican-Caribbean-Central American origin), and onsilverleaf nightshade, Solanum elaeagnifolium(native weed widely distributed). M.elatior adults laid 84 to 97% of their egg masses onS. viarum, and 3 to 16% on S. melongena. Non-choice host-specificity tests were also conducted in quarantine in which M. elatior adults and neonate larvae were exposed to 17 and 19 plant species, respectively. Tests with the neonates indicate that this insect was able to complete its development on S. viarum, S. torvum, S. melongena, and S. capsicoides. Although some adult feeding and oviposition occurred on S.melongena in quarantine on potted plants in small cages, no feeding or oviposition by M. elatiorwas observed in field experiments conducted in Brazil. Surveys in unsprayed S. melongena fields in Argentina and Brazil indicated that M. elatioris not a pest of S. melongena in South America. The evidence obtained from the South-American field surveys, Brazil open-field experiments, and Florida quarantine host specificity tests indicate that M. elatior causes significant feeding damage toS. viarum, and does not represent a threat to S. melongena crops in the USA. Therefore an application for permission to releaseM. elatior against S. viarum in the USA was submitted in October 1998. This revised version was published online in July 2006 with corrections to the Cover Date.     

Pre-release evaluation of Heikertingerella sp. as a potential biocontrol agent for Tecoma stans in South Africa

Native to Central America, Tecoma stans (L.) Juss ex Kunth var. stans (Bignoniaceae) is a small tree that is invasive in South Africa and neighbouring countries. The plant was targeted for biological control in South Africa in 2003, with two insect agents released and established so far. The root-feeding flea beetle, Heikertingerella sp. (Coleoptera: Galerucinae: Alticini), was imported from Mexico as an additional biocontrol agent and its biology and host specificity was assessed under quarantine conditions. The beetle displayed a generation time (i.e. from adult to adult) of 49 to 67 days, ensuring four annual generations under laboratory conditions. The beetle's larval and adult stages inflicted high levels of damage on the root system and the leaves of T. stans, respectively. No-choice tests with 40 test-plant species revealed adult feeding on only two non-target species, Tecoma × alata and T. capensis (Thunb.) Spach, with feeding four times higher on T. stans. Larvae developed to adulthood on T. stans only. Multi-choice tests involving the three Tecoma species confirmed these trends, demonstrating that Heikertingerella sp. is host specific. Since T. × alata is a hybrid of T. stans with invasive tendencies, any unlikely attacks by Heikertingerella sp. would be inconsequential in South Africa. The native T. capensis, which suffered little leaf damage and produced no F1 adults, is also at minimal risk of attack. We conclude that Heikertingerella sp. is a suitable biocontrol agent for T. stans and that permission for its release in South Africa be sought.     

Field and laboratory studies to determine the suitability of Cissoanthonomus tuberculipennis (Coleoptera: Curculionidae) for release against Cardiospermum grandiflorum (Sapindaceae) in South Africa

Cardiospermum grandiflorum is an invasive creeper that was targeted for biological control in South Africa in 2003. To determine ecological host range of its natural enemies, surveys were conducted on C. grandiflorum and 11 other Sapindaceae at 40 sites in the weed's native range (Argentina). These surveys indicated that the seed-feeding weevil Cissoanthonomus tuberculipennis was restricted to C. grandiflorum, and that it was among the common natural enemies, occurring at most sites where C. grandiflorum was recorded. Open-field tests were conducted under natural conditions in Argentina to determine the host preference of C. tuberculipennis and other natural enemies of C. grandiflorum among three Cardiospermum species. These tests revealed that C. tuberculipennis and the bug Gargaphia sp. were restricted to C. grandiflorum though the latter subsequently developed on non-target Cardiospermum species in the laboratory. C. tuberculipennis was found to be highly damaging, destroying up to 44% of the seeds per plant in Argentina. In all the host-specificity tests, including no-choice, paired-choice and multi-choice tests, C. tuberculipennis only fed and developed on C. grandiflorum. Failure of C. tuberculipennis to feed and develop on all congeners of C. grandiflorum shows that the weevil is highly host-specific to the target weed. Results of host-specificity tests, open field tests and long-term monitoring of C. tuberculipennis populations demonstrate that the weevil poses no threat to non-target plant species, and therefore safe for release against C. grandiflorum in South Africa. Permission to release C. tuberculipennis in South Africa has been granted by the relevant regulatory authorities.     

Gratiana boliviana, a potential biocontrol agent of Solanum viarum: Quarantine host-specificity testing in Florida and field surveys in South America

Host-specificity tests andfield surveys were conducted to determine thesuitability of the tortoise beetleGratiana boliviana Spaeth (Coleoptera:Chrysomelidae) from Argentina for classicalbiological control of Solanum viarumDunal (Solanaceae) in the USA. Thehost-specificity tests were conducted at theFlorida Department of Agriculture and ConsumerServices-Division of Plant Industry quarantinefacility in Gainesville, Florida (USA). Multiple-choice host-specificity tests wereconducted in small cages using 123 plantspecies in 35 families. Adults fedsignificantly (>41% of the leaf area offeredwas damaged) on the target weed(S. viarum), and fed lightly (<20%) onSolanum torvum Sw. (noxious weed native towest-Africa). Adults did some exploratoryfeeding (<5%) on eggplant, Solanummelongena L. (economic crop), Solanumelaeagnifolium Cav. (major agricultural weedin the western US), and on Solanumtampicense Dunal (weed of Central Americanorigin). No feeding was observed on any of theother 118 plant species that were testedincluding another 21 Solanum species.G. boliviana adults laid an average of 68eggs per female on S. viarum, 5 eggs perfemale on S. torvum, and an average of0.2 eggs on eggplant. No-choicehost-specificity tests were also conducted inwhich G. boliviana adults and neonatelarvae were exposed to 19 and 22 plant speciesrespectively. Tests with the neonatesindicated this insect was able to complete itsdevelopment only on S. viarum (67%reached the pupae stage). The no-choice testswith adults indicated that this insect fed,laid eggs, and completed development only onS. viarum. The unsprayed eggplant fieldsthat were surveyed in its natural range inArgentina, Brazil, Paraguay, and Uruguay fromJune 1997 to March 2000 indicated thatG. boliviana is not a pest of eggplants in SouthAmerica. Therefore, a petition for fieldrelease of G. boliviana for classicalbiological control of S. viarum in theUSA was submitted in April 2000.     

NEW ARRENURUS SPECIES (ACARI,HYDRACHNELLAE, ARRENURIDAE) FROM SOUTHERN AFRICA

SUMMARY

Five new Arrenurus spp, from Southern Africa are described: A. amoenus sp. nov. from Natal, A. agnewi sp. nov., A. curtipalpus sp. nov., A. pedatus sp. nov. and A. cavatus sp. nov. from Botswana. The species from Natal came from an older collection belonging to the National Institute for Water Research. The species from Botswana were collected recently by Dr J.D. Agnew¹

The water mite fauna of South Africa is only partly known. Therefore it is important that collectors should know that alcohol and formalin are not suitable fixatives. Fixing and storing is most successful in the following mixture: 5 parts glycerin, 2 parts glacial acetic acid and 3 parts water.     

Revision of Tegyrius (Coleoptera: Chrysomelidae: Galerucinae: Alticini), with descriptions of eight new species

The flea beetle genus Tegyrius Jacoby, 1887 (Coleoptera: Chrysomelidae) associated with Piperaceae is revised. Eight new species, namely Tegyrius agasthyai sp. nov. , Tegyrius dalei sp. nov. , Tegyrius nigrotibialis sp. nov. , Tegyrius pucetibialis sp. nov. , Tegyrius radhikae sp. nov. , and Tegyrius tippui sp. nov. , from India, and Tegyrius anupama sp. nov. and Tegyrius buddhai sp. nov. , from Sri Lanka, are described and illustrated. Key to species and host plant information are also provided. Tegyrius piceus Kimoto, 2001 is transferred to Longitarsus Latreille, 1829 (new combination); Tegyrius antennatus ( Medvedev, 2001 ), Tegyrius bicolor ( Medvedev, 2001 ) (both earlier Lankaphthona), and Tegyrius keralaensis ( Doeberl, 2003 ) (earlier Ogloblinia) are proposed as new combinations.     

A new family of Gonyleptoidea from South America (Opiliones,Laniatores)

A new family of Laniatores, Gerdesiidae fam. nov., is proposed based on molecular and morphological evidence. Data also indicate that this new family is the sister family of Tricommatidae. Gerdesiidae fam. nov. has a disjunct distribution, occurring in northern South America (Peru, Brazilian Amazon) and at a spot in south‐eastern Brazil (Minas Gerais State). The new family is composed of two genera: Gerdesius Roewer, 1952 (type genus) and G onycranaus gen. nov. (type species G onycranaus androgynus sp. nov. ). We propose the synonymy of Huralvioides H. Soares, 1970 with Gerdesius Roewer, 1952 based on molecular and morphological evidence. Three new species are described: G erdesius mapinguari sp. nov. (type locality: Brazil, Amazonas, Manaus, Reserva Km 41); G onycranaus androgynus sp. nov. (type locality: Brazil, Minas Gerais, Conceição do Mato Dentro); and an obligate cave‐dwelling species, G onycranaus pluto sp. nov. (type locality: Brazil, Minas Gerais, Morro do Pilar). © 2015 The Linnean Society of London     

The tortoise beetle Physonota maculiventris (Chrysomelidae: Cassidinae) is suitable for release against the weedy Mexican sunflower Tithonia diversifolia (Asteraceae) in South Africa

The biology and host range of the defoliating beetle Physonota maculiventris Boheman (Chrysomelidae: Cassidinae) were studied in quarantine to determine its suitability for release as a biological control agent against Mexican sunflower, Tithonia diversifolia (Hemsl.) A. Gray (Asteraceae), in South Africa. Females laid 5.25?±?0.25 (mean?±?SE) egg batches during their lifetimes, with each batch consisting of approximately 33 eggs. Larvae were highly gregarious as early instars and both larvae and adults fed voraciously, often defoliating the plants completely. The life cycle of the beetle was completed in 67.5?±?7.5 days under quarantine conditions. Among the 58 test plant species subjected to no-choice tests, P. maculiventris developed successfully on T. diversifolia and some sunflower (Helianthus annuus L.) cultivars. However, only minor damage was recorded on non-target species, notably the exotic weed Xanthium strumarium L. and some H. annuus cultivars. Also, survival to adulthood was considerably lower on sunflower cultivars than on the target weed during these tests. During choice tests, P. maculiventris oviposited and developed successfully on T. diversifolia only, with only minor feeding damage on some H. annuus cultivars, suggesting that the beetle’s field host range will be confined to the target weed. Risk analysis also showed that P. maculiventris presents an extremely low risk to non-target plant species (e.g. within the tribe Heliantheae and other close relatives). The study concluded that P. maculiventris is safe for release in South Africa and an application for its release is being considered by the relevant South African regulatory authorities.     

Impact of two specialist insect herbivores on reproduction of horse nettle,Solanum carolinense

The frequency of coevolution as a process of strong mutual interaction between a single plant and herbivore species has been questioned in light of more commonly observed, complex relationships between a plant and a suite of herbivore species. Despite recognition of the possibility of diffuse coevolution, relatively few studies have examined ecological responses of plants to herbivores in complex associations. We studied the impact of two specialist herbivores, the horse nettle beetle, Leptinotarsa juncta, and the eggplant flea beetle, Epitrix fuscula, on reproduction of their host, Solanum carolinense. Our study involved field and controlled-environment experimental tests of the impact on sexual and potential asexual reproduction of attack by individuals of the two herbivore species, individually and in combination. Field tests demonstrated that under normal levels of phytophagous insect attack, horse nettle plants experienced a reduction in fruit production of more than 75% compared with plants from which insects were excluded. In controlled-environment experiments using enclosure-exclosure cages, the horse nettle's two principal herbivores, the flea beetle and the horse nettle beetle, caused decreases in sexual reproduction similar to those observed in the field, and a reduction in potential asexual reproduction, represented by root biomass. Attack by each herbivore reduced the numbers of fruits produced, and root growth, when feeding in isolation. When both species were feeding together, fruit production, but not root growth, was lower than when either beetle species fed alone. Ecological interactions between horse nettle and its two primary herbivores necessary for diffuse coevolution to occur were evident from an overall analysis of the statistical interactions between the two herbivores for combined assessment of fruit and vegetative traits. For either of these traits alone, the interactions necessary to promote diffuse coevolution apparently were lacking.     

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.     

Ammonites of Tethyan origin from the Ryazanian of the Russian platform: Genus <Emphasis Type="Italic">Subalpinites</Emphasis> Mazenot

The ammonite genus Subalpinites is known from the Berriasian of southern and central Europe, North Africa, Mangyshlak, and Ryazanian Stage of Central Russia. New species are described: S. gruendeli sp. nov., S. faurieformis sp. nov., S. remaneiformis sp. nov. These species and also S. krischtafowitschi Mitta characterize the lower subzone of the Riasanites rjasanensis Zone in the Moscow Region. The upper subzone of this zone in the Ryazan Region contained members of Subalpinites identified in open nomenclature.     

Climate constrains the establishment and proliferation of Anthonomus santacruzi,a flower-feeding biological control agent of the invasive weed Solanum mauritianum in South Africa

The flowerbud-feeding weevil Anthonomus santacruzi Hustache (Coleoptera: Curculionidae) was released in South Africa in 2008 for the biological control of the invasive tree Solanum mauritianum Scopoli (Solanaceae). The weevil was widely deployed throughout KwaZulu-Natal province, which supports large S. mauritianum infestations, and has become well established in its warmer coastal regions. The aim of this study was to provide field evidence that climate is constraining the weevil’s distribution in South Africa. Solanum mauritianum populations were sampled at 23 sites across an altitudinal gradient in KwaZulu-Natal to determine A. santacruzi densities in relation to food availability and climatic variables. Despite significantly higher amounts of floral material on S. mauritianum at the higher altitude inland sites, A. santacruzi numbers were significantly higher at the lower altitude coastal sites. There was thus a significant negative relationship between A. santacruzi numbers and altitude and significant positive relationships between A. santacruzi numbers and both temperature and humidity. Neither rainfall nor food availability influenced A. santacruzi numbers, although lower amounts of floral material at the coastal sites may well have been caused by higher weevil densities at these sites. Anthonomus santacruzi was absent at only three sites, all at higher altitudes, further demonstrating that conditions in coastal or low-altitude regions are favourable for establishment and population proliferation. Future release efforts in KwaZulu-Natal, but also in other South African provinces, should thus be focused on coastal regions and inland regions that are below 1000 m above sea level.