25th Asian-Pacific Weed Science Society Conference on “Weed Science for Sustainable Agriculture, Environment and Biodiversity”, Hyderabad, India during 13-16 October, 2015

Field host range and host specificity of Anomalococcus indicus (: Lecanodiaspididae): a potential biological control agent for prickly acacia sp. Indica in Australia

A. Balu1, S. Murugesan1, P. Senthilkumar1 and K. Dhileepan2 1Institute of Forest Genetics and Tree Breeding, Coimbatore, Tamil Nadu, 641 002, India; 2Biosecurity Queensland, Department of Employment, Economic Development and Innovation, Alan Fletcher Research Station, Sherwood, Queensland 4075, Australia. 2Email: [email protected]

Prickly acacia (Vachellia nilotica subsp. indica), a surveys in southern India, the scale was not on other native of the Indian subcontinent, is a serious weed of the previously reported hosts. grazing areas of northern Australia and is a target for classical biological control. genotype and climatic similarities has Host specificity studies accelerated a five year biological control project based in No- choice test India since September 2008. Three years systematic surveys on prickly acacias at its natural host range in India revealed 94 The hatching nymph from female egg sac is to be finding difficultly, but after 3 to 4 molt it’s visible. There appeared to different species of belonging to five families (Dhileepan et al. 2013).The sap sucking be no dispersal on the locally available Acacia species and Anomalococcus indicus is one of the most promising agents there was no young once found on all of these species, V. nilotica sub species and V. tortilis until 60 days experiment prioritized as a potential biological control agent for further studies based on its field host range, field abundance and began (Table.1). The nymphs spreading were noticed in 19 ± damage levels (Dhileepan et al. 2013). A. indicus available 2.64, 23 ± 3.11 and 31 ± 4.03 days on prickly acacia and V. nilotica sp. tomentosa and V. tortilis respectively. throughout the year was found more abundant in summer and late spring (January – March and September- December) in moving were evident on stems of these species. However the Tamil Nadu, India and it was previously recorded on V. intensity of the scale population significantly varied among the infested plant species (Fig. 1). High population and nilotica, V. farnesiana, V. leucophloea, Senegaliachundra, Ziziphusmauritiana (Baksha and Islam 1996). This paper gradually increased trend was noticed on the control plant describes the field host range and host specificity studies and (680 ± 2.84), followed that the V. nilotica sp. tomentosa had second highest population (450 ± 3.64) after end of the study; also discusses the possibility of using this insect species as a potential biological control agent of prickly acacia. rest of the species had known number of scales population. Severe infestation was noticed only on V. nilotica sub species METHODOLOGY and the seedlings totally dried with 90 days. The experiment Field host rage also revealed that the percent of the nymphs developed to adults varied among the infected test plant species (Table. 1). A systematic survey was carried out in 2008-2011 in the About 64±3.45% nymphs were developed to adults on control states in Tamil Nadu and Karnataka. The survey sites were , similarly 51 ± 3.27% nymphs can mature as adults on V. predominantly forestry plantations in tank beds, and isolated nilotica sp. tomentosa. The least percentage (12 ± 5.61) was plants on roadside and tank bunds of agricultural lands. The noticed on test plant species V. farnesiana. survey efforts were more systematic and rigorous; where different districts and areas were covered at different months on the basis of accessibility representing varied climatic Table 1. Proportion of A. indicus, nymphsthat developed into regions and sampled at quarterly intervals. During the adult on various non-target plants in no-choice host surveys, other acacia species nearby and reported species specificity tests were also sampled to monitor the natural host range of prioritized agents recorded on A. nilotica sp. indica. Duration of % Nymph % Test plants spreading developed seedlings Host specificity studies (days) to adult mortality No-choice host specificity testing of A. indicus was Acacia nilotica ssp. indica (control) 19 ± 2.64 64 ± 3.45 100 ± 0.0 carried out at the insectary of Institute of Forest Genetics and Acacia nilotica sp. tomentosa 23 ± 3.11 51 ± 3.27 100 ± 0.0 Acacia tortilis 31 ± 4.03 16 ± 5.48 10 ± 2.59 Tree Bradding, Coimbatore by exposing with gravid females Acacia farnesiana 0 ± 0.0 0 ± 0.0 0 ± 0.0 infested stem cuttings. The test plants used in the study were Acacia ferruginea 0 ± 0.0 0 ± 0.0 0 ± 0.0 Vachellia nilotica sp. tomentosa (Benth.) Kyal. & Boatwr., Acacia auriculiformis 0 ± 0.0 0 ± 0.0 0 ± 0.0 Vachelliatortilis (Forssk.) Galasso and Banfi, Vachellia Acacia 0 ± 0.0 0 ± 0.0 0 ± 0.0 planifrons Wright and Arn., Vachellia leucophloea (Roxb.) Acacia mellifera 0 ± 0.0 0 ± 0.0 0 ± 0.0 Maslin, Seigler and Ebinger, mellifera (M. Vahl) Acacia planiferons 0 ± 0.0 0 ± 0.0 0 ± 0.0 Seigler and Ebinger, Senegalia catechu (L.f.) P.J.H.Hurter and Acacia leucophloea 0 ± 0.0 0 ± 0.0 0 ± 0.0 Mabb., Senegalia ferruginea (DC.) Pedley, Vachellia Piper nigrum 0 ± 0.0 0 ± 0.0 0 ± 0.0 arriculiformis A.Cunn. ex Benth., Vachellia farnesiana (L.) Mean of twenty replicates (± standard error). Willd., (R.T. Baker) (all ) and Piper nigrum (Piperaceae). Each plant species was replicated twenty times and each test plant tied with 15 cm infested stem cutting with10 gravid females. Data on duration to spreading and number of adults, nymphs survived on the tests plants were statistically analyzed. RESULTS Field host range All the survey sites had the incidence of A. indicus which was recorded commonly on V. nilotica subspecies, V. nilotica sp. indica, V. nilotica sp. tomentosa, V. nilotica sp. subalata and V. nilotica sp. cupressiformis. In few occasions, the scale insect was recorded on V. tortilis and asingle Fig 1. Proportion of A. indicus surviving on various test plants occasion on A. leucophloea in survey. During the field by no-choice host specificity tests over time

6 8 25th Asian-Pacific Weed Science Society Conference on “Weed Science for Sustainable Agriculture, Environment and Biodiversity”, Hyderabad, India during 13-16 October, 2015

CONCLUSION REFERENCES The scale insect Anomalococcus indicus is host specific Baksha MW and Islam MR. 1996. Mortality of babul (Acacia nilotica) on V. nilotica sub species in field. Preliminary tests thus reveals caused by the scale insect, Anomalococcus indicus and its control. that the scale insects were abundant and causing severe Indian Journal of Forestry 19: 355-360. damaging on all stages of V. nilotica sp. indica in Tamil Nadu, Kunjithapatham Dhileepan, Ayyapillai Balu, Selvaraj Murugesan, India. The scale has extensive generations and produced Ponnusamy Senthilkumar and Roger G. Shivas. 2013. Survey and enormous population in a year and it might quickly reach prioritisation of potential biological control agents for prickly damaging population level; if in Australia, free for natural acacia (Acacia nilotica sub sp. indica) in southern India. Biocontrol enemies, hurriedly killed the prickly acacia than the native. Science and Technology 23(6): 646-664.

Exotic weed seeds in the imported germplasm

Mool Chand Singh*, Anjula Pandey and Dinesh Chand ICAR-National Bureau of Plant Genetic Resources, New Delhi 110 012, India *Email: [email protected]

The import of seeds and planting material meant for Percentage incidence on number basis, viability and weed risk research in various crop improvement programs is a potential assessment score of different weed seeds were determined. and inadvertent source of introducing exotic weeds into new Weed seeds were identified on the basis of their areas and this may cause severe damage to crop production. morphological characters and in few cases, weed seeds were National Bureau of Plant Genetic Resources is the nodal subjected to grow out test in isolation and identified on the agency to undertake the quarantine processing of germplasm basis of vegetative and floral characters. All the weed seeds including transgenic material introduced into the country for were devitalized using heat treatment at 1200 C for 30 minutes. research purposes. Exotic weed seeds have been intercepted on many occasions from seed material (Singh et al. 2010). In RESULTS view of the above, seeds and planting material imported A total of 32 weed species were intercepted in 166 through the Bureau was screened for weed seeds especially samples. Among 32 weed species, 17 are exotic to India (Holm for the presence of exotic weed seeds. et al. 1997). Maximum exotic weeds were intercepted in the METHODOLOGY seeds imported from Switzerland followed by USA. Weed seeds were separated from contaminated samples by During 2010-12, a total of 183862 seed samples were mechanical cleaning and weed free material was released to imported from different countries. All samples were examined the importers. It is evident that all the weed seeds were found for weed seeds by passing through sieves of different pore viable even after long storage. Weed risk assessment (WRA) sizes. Then each sample was spread in a thin uniform layer on score ranged from 07 to 18 and revealed that all the intercepted a clean white drawing sheet and examined with the help of exotic weeds have potential to become problematic weeds in illuminated magnifier. All weed seeds were collected and then India. Particulars of weed seeds, their percentage incidence, segregated into different types on the basis of their shape, viability and WRA score are given in Table 1. size, colour, texture and presence of any attachment. Table 1. Exotic weeds intercepted, their percentage, viability and WRA score

Per cent Weed species Crop Country Viability (%) WRA score incidence Bifora testiculata Triticum aestivum Australia, Mexico 0.009 25 08 Bromus tectorum T.aestivum Switzerland 0.004 30 16 Cichorium spinosum Trifolium alexandrinum Egypt 0.023 58 16 Croton capitatus Oryza sativa USA 0.008 10 10 Echinochloa crus-pavonis O. sativa Argentina 0.002 72 18 Galium trifidum T. aestivum Germany 0.003 20 11 Jacquemontiat amnifolia O. sativa USA 0.001 12 10 Lamiumamplexicaule Medicago lupulina Switzerland 0.006 16 08 Lithospermum arvense Medicago sp. New Zealand 0.007 55 09 Polygonum argyrocoleon T.aestivum Mexico 0.012 60 12 Silenenoctiflora Brassica oleracea Netherlands 0.002 30 13 Sinapsis arvensis O. sativa USA 0.038 60 10 Trifolium bifidum Pennisetum purpureum Ethiopia 0.002 70 08 Trifolium pretense Trigonellafoenum graecum Syria 0.021 75 07 Vicia angustifolia M. lupulina Switzerland 0.015 70 12 Vicia tetrasperma M. lupulina Switzerland 0.001 80 11 Vicia villosa M. lupulina Switzerland 0.005 60 10

CONCLUSION REFERENCES Observations indicate that import of seeds could be Holm LR, Doll J, Holm E, Panch J and Herberger J. 1997. World Weeds: source of introduction and dissemination of dangerous and Natural Histories and Distribution. John Wiley & Sons, Inc, 605 potentially dangerous exotic weed seeds. It is necessary to Third Avenue, New York, USA. evolve suitable quarantine measures/regulations to prevent Singh Moolchand, Lal B, Agarwal PC, Pandey A, Joshi KD, Chand D and introduction of such exotic weeds into our country. Khetarpal RK. 2010. Weed seeds intercepted in the germplasm of Trifoliums species imported from USA and Egypt. Indian Journal of Plant Genetic Resources 23(1): 136-40.

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