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Kunjithapatham Dhileepan - One of the best experts on this subject based on the ideXlab platform.
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the host specificity of anomalococcus indicus ayyar hemiptera lecanodiaspididae a potential biological control agent for prickly acacia Vachellia nilotica ssp indica in australia
Biocontrol Science and Technology, 2018Co-Authors: Dianne B J Taylor, Kunjithapatham DhileepanAbstract:Prickly acacia, Vachellia nilotica ssp. indica (Benth.) Kyal. & Boatwr, is a significant weed of northern Australia and has been a target of weed biological control in Australia since the 1980s. Following native range surveys in India, the scale insect Anomalococcus indicus Ayyar was identified as the most promising agent and was imported into Australia for further research. A. indicus is a major pest of prickly acacia on the Indian subcontinent, where it causes shoot tip dieback and plant death. Despite field observations suggesting the species was specific to V. nilotica, A. indicus completed development on 17 of the 84 non-target plant species tested during no-choice host specificity trials under quarantine conditions. Of these, Acacia falcata,V. bidwillii, V. sutherlandii and Neptunia major supported high numbers of mature females in all replicates. All of these species were utilised in choice trials. Combined risk scores indicate that V. sutherlandii, N. major and A. falcata may be attacked in the field. Due to the limited ability of scale insects to disperse, only those non-target species that occur on the Mitchell grass downs (i.e. V. sutherlandii) are considered to be at risk. Nevertheless, in view of the disparity between quarantine test results and the observed field host specificity of A. indicus in India, field trials are currently being conducted in India using Australian native species on which complete development has occurred. The future of A. indicus as a biological control agent for prickly acacia in Australia will be determined once results from these field trials are known. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.
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the leaf feeding geometrid isturgia disputaria guenee a potential biological control agent for prickly acacia Vachellia nilotica subsp indica benth kyal boatwr mimosaceae in australia
Journal of Biological Control, 2014Co-Authors: A Balu, S Murugesan, P Senthilkumar, R Mahalakshmi, Kunjithapatham DhileepanAbstract:Prickly acacia ( Vachellia nilotica subsp. indica ), a native multipurpose tree in India, is a weed of National significance, and a target for biological control in Australia. Based on plant genetic and climatic similarities, native range surveys for identifying potential biological control agents for prickly acacia were conducted in India during 2008-2011. In the survey leaf-feeding geometrid, Isturgia disputaria Guenee (syn. Tephrina pulinda ), widespread in Tamil Nadu and Karnataka States, was prioritized as a potential biological control agent based on field host range, damage potential and no choice test on non target plant species. Though the field host range study exhibited that V. nilotica ssp. indica and V. nilotica ssp. tomentosa were the primary hosts for successful development of the insect, I. disputaria , replicated no - choice larval feeding and development tests conducted on cut foliage and live plants of nine non-target acacia test plant species in India revealed the larval feeding and development on three of the nine non-target acacia species, V. tortilis , V. planiferons and V. leucophloea in addition to the V. nilotica ssp. indica and V. nilotica ssp. tomentosa . However, the proportion of larvae developing into adults was higher on V. nilotica subsp. indica and V. nilotica subsp. tomentosa , with 90% and 80% of the larvae completing development, respectively. In contrast, the larval mortality was higher on V. tortilis (70%), V. leucophloea (90%) and V. planiferons (70%). The no-choice test results support the earlier host specificity test results of I. disputaria from Pakistan, Kenya and under quarantine in Australia. Contrasting results between field host range and host use pattern under no-choice conditions are discussed.
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localization of feeding of anomalococcus indicus hemiptera lecanodiaspididae and supplementary biological notes towards the biological management of the invasive tree Vachellia nilotica indica fabales mimosoideae in north eastern australia
Annales De La Societe Entomologique De France, 2013Co-Authors: Anwar N Khan, Kunjithapatham Dhileepan, Anantanarayanan Raman, Dennis HodgkinsAbstract:. Management of the invasive Vachellia nilotica indica infesting tropical grasslands of Northern Australia has remained unsuccessful to date. Presently Anomalococcus indicus is considered a potential agent in the biological management of V. n. indica. Whereas generic biological details of A. indicus have been known, their feeding activity and details of their mouthparts and the sensory structures that are associated with their feeding action are not known. This paper provides details of those gaps. Nymphal instars I and II feed on cortical-parenchyma cells of young stems of V. n. indica, whereas nymphal instars III and adult females feed on phloem elements of older shoots. Nymphal instars and adults (females) trigger stress symptoms in the feeding tissue with cells bearing enlarged and disfigured nuclei, cytoplasmic shrinkage, cytoplasmic trabeculae, abnormal protuberances and uneven cell wall thickening, unusual cell membrane proliferation, and exhausted and necrosed cells. Continuous nutrient extraction by A. indicus can cause stem death. We provide evidence that A. indicus, by virtue of its continuous feeding activity and intense population build up, can be an effective biological-management agent to regulate populations of V. n. indica in infested areas. © 2014 © 2014 Societe entomologique de France.
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life history of anomalococcus indicus hemiptera lecanodiaspididae a potential biological control agent for prickly acacia Vachellia nilotica ssp indica in australia
Biocontrol Science and Technology, 2013Co-Authors: Dianne B J Taylor, Kunjithapatham DhileepanAbstract:Babul scale Anomalococcus indicus Ramakrishna Ayyar, a major pest of Vachellia nilotica (L.f.) P.J.H. Hurter & Mabb. on the Indian subcontinent, has been identified as a potential biocontrol agent for prickly acacia V. nilotica subsp. indica (Benth.) Kyal. & Boatwr. in Australia and was imported from southern India for detailed assessment. The life history of A. indicus under controlled glasshouse conditions was determined as a part of this assessment. Consistent with other scale species, A. indicus has a distinct sexual dimorphism which becomes apparent during the second instar. Females have three instars, developing into sexually mature nymphs after 52 days. The generation time from egg to egg was 89 days. Females are ovoviviparous, ovipositing mature eggs into a cavity underneath their body. An average of 802 +/- 114 offspring were produced per female. Reproductive output was closely associated with female size; larger females produced more than 1200 offspring. Crawlers emerged from beneath the female after an indeterminate period of inactivity. They have the only life stage at which A. indicus can disperse, though the majority settle close to their parent female forming aggregative distributions. In the absence of food, most crawlers died within three days. Males took 62 days to develop through five instars. Unlike females, males underwent complete metamorphosis. Adult males were small and winged, and lived for less than a day. Parthenogenesis was not observed in females excluded from males. The life history of A. indicus allows it to complement other biological control agents already established on prickly acacia in Australia.
Dhileepan Kunjithapatham - One of the best experts on this subject based on the ideXlab platform.
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Genetic identity of Australian prickly acacia (Vachellia nilotica, Fabales: Mimosoideae) – assessing the target for biological control
'Elsevier BV', 2021Co-Authors: Comben, David F., Dhileepan Kunjithapatham, Mcculloch, Graham A., Walter, Gimme H.Abstract:Prickly acacia (Vachellia nilotica) has been the target of biological control programmes in Australia for over three decades, with little success. Control efforts may have been hindered by poor characterisation of the plants in Australia, and the ambiguous taxonomy of the species. Nine subspecies of this weed have been described, with only one subspecies identified in Australia (subsp. indica), though previous genetic screening identified a unique genotype in Australia that allegedly did not match any of the previously described subspecies (dubbed the “Pakistan genotype”). We used gene sequencing to characterise this weed in Australia, and to assess the native range distribution of the invasive subspecies. Two widespread ITS1 haplotypes were identified from 25 localities across northern Australia, corresponding to subsp. indica and the undescribed “Pakistan genotype”. Many plants were heterozygous at the ITS1 locus, indicating plants with the distinct genotypes are freely interbreeding. The “Pakistan genotype”, which has no defining morphological characters, was found across the native range of subsp. indica (including Ethiopia, where this subspecies has only recently been detected). The “Pakistan genotype” is not, in other words, a distinct subspecies, but simply represents genetic variation within subsp. indica. No genetic structuring was found across the native distribution of subsp. indica, so the precise provenance of the Australian plants could not be determined. Future studies should use microsatellites or genotyping-by-sequencing approaches to provide a finer-scale assessment of the provenance of the Australian plants
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Biological control of prickly acacia (Vachellia nilotica subsp. indica): New gall-inducing agents from Africa
2019Co-Authors: Dhileepan Kunjithapatham, Shi Boyang, Callander Jason, Taylor Dianne, Teshome Mindaye, Neser Stefan, Diagne Nathalie, King AnthonyAbstract:Biological control is the most economically viable management option for prickly acacia (Vachellia nilotica subsp. indica), a serious weed of grazing areas in western Queensland, Australia. Biological control efforts so far have focused on agents from Pakistan, Kenya, South Africa and India, with limited success to date. Hence, the search for new agents, focusing on gall-inducers, was redirected to Ethiopia and Senegal, based on plant genotype and climate matching. Surveys were conducted on V. nilotica subspecies with moniliform fruits including the invasive subspecies indica. Prospective biological control agents have been identified based on damage potential, field host range and climate match. A gall thrips (Acaciothrips ebneri [Karny]) inducing shoot-tip rosette galls, a gall mite (Aceria sp. 3) deforming leaflets, rachides and shoot-tips in Ethiopia and Senegal and a tephritid fly (Notomma mutilum [Bezzi]) inducing stem-galls in Senegal have been prioritized for further studies. The gall thrips from Ethiopia has been imported into quarantine in Brisbane, Australia and host specificity tests are in progress. The eriophyid gall mite from Ethiopia has been imported into quarantine in Pretoria, South Africa and host specificity tests are also in progress there. Results to date suggest that both agents are highly host specific at the subspecies level of the target weed. Future research will focus on the host specificity testing of the tephritid gall fly from Senegal which has been imported in quarantine in Brisbane, Australia
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Implications of the changing phylogenetic relationships of Acacia s.l. on the biological control of Vachellia nilotica ssp. indica in Australia
'Wiley', 2019Co-Authors: Taylor, Dianne B. J., Dhileepan KunjithapathamAbstract:Plant relationships have implications for many fields including weed biological control. The use of DNA sequencing and new tree building algorithms since the late 1980s and early 1990s have revolutionised plant classification and has resulted in many changes to previously accepted taxonomic relationships. It is critical that biological control researchers stay abreast of changes to plant phylogenies. One of the largest plant genera, Acacia, has undergone great change over the past 20 years and these changes have ramifications for weed biological control projects in a number of countries. Vachellia nilotica (prickly acacia) is a major weed in Australia, originating from the Indian subcontinent and Asia, and it has been a target for biological control since 1980. Once a member of Acacia, a large (>1,000 spp.) and iconic group in Australia, prickly acacia is now part of the genus Vachellia. Current knowledge suggests that Vachellia is more closely related to mimosoid genera than it is to Acacia s.s. There has also been a recent reclassification of legume subfamilies with subfamily Mimosoideae now part of subfamily Caesalpinioideae, and four new subfamilies. In this paper we review the changes that have occurred to this group since the prickly acacia biological control project began and discuss the implications for the project. A new host test list for quarantine testing is proposed. Developed following the modernisation of the centrifugal-phylogenetic method, it is shorter than past lists, containing 46 species, although still lengthy because of the expectations of regulatory bodies, which are slower to accept advances in scientific knowledge. The list includes five Vachellia species, six “Mimoseae” species and 26 Acacia species. The number species from legume subfamilies other than the new Caesalpinioideae is greatly reduced
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Biological control of prickly acacia (Vachellia nilotica subsp. indica) in Australia: prospective agents from Ethiopia and Senegal
Asian-Pacific Weed Science Society, 2017Co-Authors: Dhileepan Kunjithapatham, Shi Boyang, Callander Jason, Teshome Mindaye, Neser Stefan, Diagne Nathalie, King, Anthony M.Abstract:Prickly acacia (Vachellia nilotica subsp. indica) is a serious weed of grazing areas in western Queensland and has the potential to spread throughout northern Australia. Biological control is the most economically viable management option for prickly acacia. Biological control efforts so far have focused on agents from Pakistan, Kenya, South Africa and India, with limited success to date. Hence, search for new biological control agents was redirected to Ethiopia and Senegal with V. nilotica subspecies with moniliform fruits, similar to subsp. indica. Surveys conducted in Ethiopia (July 2014, December 2015 and November 2016) and in Senegal (March 2017) identified natural populations of V. nilotica in the Oromia, Amhara and Afar regions in Ethiopia (subsp. indica, subsp. tomentosa and subsp. leiocarpa), and in the Kaolack and in the Senegal River Valley regions in Senegal (subsp. tomentosa and subsp. adstringens). In Ethiopia, a gall thrips (Acaciothrips ebneri) inducing shoot-tip rosette galls, a gall midge (Lopesia niloticae) inducing leaf rachis galls, and three morphologically distinct eriophyid gall mites (Aceria sp.): type-1 forming red, spherical leaflet galls; type-2 forming creamy-white fluted leaflet galls; and type-3 deforming leaflets, rachides and shoot-tips were prioritised as prospective biological control agents. In Senegal, in addition to the gall thrips, a morphologically different eriophyid gall mite (Aceria sp.) (type-4 deforming emerging leaflets and rachides) and a yet to be identified tephritid inducing stem galls were identified as prospective biological control agents. Based on damage potential, field host range, geographic range and climate match, the gall thrips from Ethiopia was imported into high-security quarantine in Brisbane, Australia and host specificity tests are in progress. The type-3 eriophyid gall mite from Ethiopia has been imported into quarantine in Pretoria, South Africa for colony establishment and host specificity testing. Future native range surveys will focus on subsp. nilotica with moniliform fruits in climatically suitable areas in Egypt
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Advancing prickly acacia management through the war on Western Weeds Initiative
2017Co-Authors: March Nathan, Vogler Wayne, Dhileepan KunjithapathamAbstract:Prickly acacia (Vachellia nilotica) is a landscape level weed problem affecting large areas of western Queensland and other areas of the state. Following high rainfall related mass germination events of 2010 – 2012, the Department of Agriculture and Fisheries (DAF) launched the War on Western Weeds (WoWW) initiative in 2013. WoWW focussed on three key areas: refining new tools and approaches; improving biosecurity systems; and, exploring biocontrol opportunities. Notable outcomes have included: refinement of misting, weed sniper and skattergun as control options; two Good Neighbour Program case studies demonstrating the practicalities of property boundary weed-free buffer zones; ecological studies as a basis for seed spread prevention actions; and, renewed biological control investigations involving searches for prospective agents in India and North Africa. Initiative results have been extended through forums, field days and publication of a decision support tool factsheet series. The increased capacity, skills, tools and motivation from the WoWW initiative are helping to achieve practical and cost-effective outcomes for prickly acacia management – helping land managers to help themselves
Ahmed Al-rawahi - One of the best experts on this subject based on the ideXlab platform.
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Complete chloroplast genomes of Vachellia nilotica and Senegalia senegal : Comparative genomics and phylogenomic placement in a new generic system
PloS one, 2019Co-Authors: Sajjad Asaf, A. U. Khan, Abdul Latif Khan, Ahmed Al-harrasi, Ahmed Al-rawahiAbstract:Vachellia and Senegalia are the most important genera in the subfamily Mimosoideae (Fabaceae). Recently, species from both genera were separated from the long-characterized Acacia due to their macro-morphological characteristics. However, this morpho-taxonomic differentiation struggles to discriminate some species, for example, Vachellia nilotica and Senegalia senegal. Therefore, sequencing the chloroplast (cp) genomes of these species and determining their phylogenetic placement via conserved genes may help to validate the taxonomy. Hence, we sequenced the cp genomes of V. nilotica and S. senegal, and the results showed that the sizes of the genomes are 165.3 and 162.7 kb, respectively. The cp genomes of both species comprised large single-copy regions (93,849~91,791 bp) and pairs of inverted repeats (IR; 26,093~26,008 bp). The total numbers of genes found in the V. nilotica and S. senegal cp genomes were 135 and 132, respectively. Approximately 123:130 repeats and 290:281 simple sequence repeats were found in the S. senegal and V. nilotica cp genomes, respectively. Genomic characterization was undertaken by comparing these genomes with those of 17 species belonging to related genera in Fabaceae. A phylogenetic analysis of the whole genome dataset and 56 shared genes was undertaken by generating cladograms with the same topologies and placing both species in a new generic system. These results support the likelihood of identifying segregate genera from Acacia with phylogenomic disposition of both V. nilotica and S. senegal in the subfamily Mimosoideae. The current study is the first to obtain complete genomic information on both species and may help to elucidate the genome architecture of these species and evaluate the genetic diversity among species.
Dennis Hodgkins - One of the best experts on this subject based on the ideXlab platform.
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biological management of the invasive Vachellia nilotica ssp indica benth kyal boatwr fabales mimosoideae in tropical australia stress inducing potential of anomalococcus indicus ramakrishna insecta hemiptera coccoidea lecanodiaspididae an agent of promise
Arboricultural Journal, 2014Co-Authors: Anwar N Khan, K Dhileepan, Anantanarayanan Raman, Anamika Sharma, Dennis HodgkinsAbstract:Vachellia nilotica ssp. indica (hereafter, V. n. indica) is an important tree weed in Australia. Its dense populations induce undesirable changes in the vast areas of northern Australia. Because chemical and mechanical management options appear unviable for various reasons, biological management of this tree is considered a better option. Among the many trialled arthropods in Australian context, Anomalococcus indicus, a lecanodiaspid native to India, has been identified as a potent-candidate, since in India, its native terrain, it is the most widespread and occurs throughout the year. Severe infestations of A. indicus cause defoliation, wilting and death of branches, and occasionally the tree. Populations of A. indicus have been brought into Australia and are being tested for its host specificity under quarantine conditions. This article reports the physiological damage and stress it inflicts in the shoots of V. n. indica. Younger-nymphal instars of A. indicus feed on cortical-parenchyma cells of young stems, whereas the older instars and adults feed from the phloem of old stems. Two conspicuous responses of V. n. indica arising in response to the feeding action of A. indicus are changes in the cell-wall dynamics and irregular cell divisions. The feeding action of A. indicus elicits a sequence of reactions in the stem tissues of V. n. indica such as differentiation of thick-walled elements in the outer cortical parenchyma, differential thickening of cells with supernumerary layers of either suberin or lignin, proliferations of parenchyma and phloem, wall thickening and obliteration of inner lumen of phloem cells, and the sieve plates plugged with callosic deposits. The responses are the culminations of interaction between the virulence factor (one or more of the salivary proteins?) from A. indicus and the resistance factor in V. n. indica. We have analysed structural changes in the context of their functions, by comparing the feeding action of A. indicus with that of other hemipteroids. From the level of stress it induces, this study confirms that A. indicus has the potential to be an effective biological management of V. n. indica in Australia. © 2014 © 2014 Taylor & Francis and Aboricultural Association.
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localization of feeding of anomalococcus indicus hemiptera lecanodiaspididae and supplementary biological notes towards the biological management of the invasive tree Vachellia nilotica indica fabales mimosoideae in north eastern australia
Annales De La Societe Entomologique De France, 2013Co-Authors: Anwar N Khan, Kunjithapatham Dhileepan, Anantanarayanan Raman, Dennis HodgkinsAbstract:. Management of the invasive Vachellia nilotica indica infesting tropical grasslands of Northern Australia has remained unsuccessful to date. Presently Anomalococcus indicus is considered a potential agent in the biological management of V. n. indica. Whereas generic biological details of A. indicus have been known, their feeding activity and details of their mouthparts and the sensory structures that are associated with their feeding action are not known. This paper provides details of those gaps. Nymphal instars I and II feed on cortical-parenchyma cells of young stems of V. n. indica, whereas nymphal instars III and adult females feed on phloem elements of older shoots. Nymphal instars and adults (females) trigger stress symptoms in the feeding tissue with cells bearing enlarged and disfigured nuclei, cytoplasmic shrinkage, cytoplasmic trabeculae, abnormal protuberances and uneven cell wall thickening, unusual cell membrane proliferation, and exhausted and necrosed cells. Continuous nutrient extraction by A. indicus can cause stem death. We provide evidence that A. indicus, by virtue of its continuous feeding activity and intense population build up, can be an effective biological-management agent to regulate populations of V. n. indica in infested areas. © 2014 © 2014 Societe entomologique de France.
Hodgkins D. S. - One of the best experts on this subject based on the ideXlab platform.
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Biological management of the invasive Vachellia nilotica ssp. indica (Benth.) Kyal. & Boatwr. (Fabales: Mimosoideae) in tropical Australia: stress-inducing potential of Anomalococcus indicus Ramakrishna (Insecta: Hemiptera: Coccoidea: Lecanodiaspididae), an agent of promise
'Informa UK Limited', 2014Co-Authors: Khan A. N., Dhileepan K., Raman A., Sharma A., Hodgkins D. S.Abstract:Vachellia nilotica ssp. indica (hereafter, V. n. indica) is an important tree weed in Australia. Its dense populations induce undesirable changes in the vast areas of northern Australia. Because chemical and mechanical management options appear unviable for various reasons, biological management of this tree is considered a better option. Among the many trialled arthropods in Australian context, Anomalococcus indicus, a lecanodiaspid native to India, has been identified as a potent-candidate, since in India, its native terrain, it is the most widespread and occurs throughout the year. Severe infestations of A. indicus cause defoliation, wilting and death of branches, and occasionally the tree. Populations of A. indicus have been brought into Australia and are being tested for its host specificity under quarantine conditions. This article reports the physiological damage and stress it inflicts in the shoots of V. n. indica. Younger-nymphal instars of A. indicus feed on cortical-parenchyma cells of young stems, whereas the older instars and adults feed from the phloem of old stems. Two conspicuous responses of V. n. indica arising in response to the feeding action of A. indicus are changes in the cell-wall dynamics and irregular cell divisions. The feeding action of A. indicus elicits a sequence of reactions in the stem tissues of V. n. indica such as differentiation of thick-walled elements in the outer cortical parenchyma, differential thickening of cells with supernumerary layers of either suberin or lignin, proliferations of parenchyma and phloem, wall thickening and obliteration of inner lumen of phloem cells, and the sieve plates plugged with callosic deposits. The responses are the culminations of interaction between the virulence factor (one or more of the salivary proteins?) from A. indicus and the resistance factor in V. n. indica. We have analysed structural changes in the context of their functions, by comparing the feeding action of A. indicus with that of other hemipteroids. From the level of stress it induces, this study confirms that A. indicus has the potential to be an effective biological management of V. n. indica in Australia. © 2014 © 2014 Taylor & Francis and Aboricultural Association
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Localization of feeding of Anomalococcus indicus (Hemiptera: Lecanodiaspididae) and supplementary biological notes: Towards the biological management of the invasive tree Vachellia nilotica indica (Fabales: Mimosoideae) in North-Eastern Australia
'Informa UK Limited', 2013Co-Authors: Khan A. N., Dhileepan K., Raman A., Hodgkins D. S.Abstract:. Management of the invasive Vachellia nilotica indica infesting tropical grasslands of Northern Australia has remained unsuccessful to date. Presently Anomalococcus indicus is considered a potential agent in the biological management of V. n. indica. Whereas generic biological details of A. indicus have been known, their feeding activity and details of their mouthparts and the sensory structures that are associated with their feeding action are not known. This paper provides details of those gaps. Nymphal instars I and II feed on cortical-parenchyma cells of young stems of V. n. indica, whereas nymphal instars III and adult females feed on phloem elements of older shoots. Nymphal instars and adults (females) trigger stress symptoms in the feeding tissue with cells bearing enlarged and disfigured nuclei, cytoplasmic shrinkage, cytoplasmic trabeculae, abnormal protuberances and uneven cell wall thickening, unusual cell membrane proliferation, and exhausted and necrosed cells. Continuous nutrient extraction by A. indicus can cause stem death. We provide evidence that A. indicus, by virtue of its continuous feeding activity and intense population build up, can be an effective biological-management agent to regulate populations of V. n. indica in infested areas. © 2014 © 2014 Société entomologique de France
