Preference and Performance of the Polymorphic Flea-beetle, Alagoasa extrema, on Selected, Weedy Lantana camara Varieties

The possible preference that the leaf-feeding flea-beetle, Alagoasa extrema Jacoby (Coleoptera: Chrysomelidae: Alticinae), might have for different South African naturalized varieties of its host plant, Lantana camara L. (Verbenaceae), was studied under quarantine laboratory conditions. Studies included adult choice trials, larval no-choice trials and multi-generation no-choice trials using five L. camara varieties. Results indicated that A. extrema exhibited a degree of varietal preference under laboratory conditions. Variety 029 White Pink proved to be the most suitable host, although the other four tested varieties were able to support viable populations of A. extrema for three consecutive generations. Should A. extrema be released as biocontrol agent for L. camara in South Africa, all five of the tested varieties should be able to support viable populations of A. extrema in the field.     

Experimental Manipulation of Restoration Barriers in Abandoned Eucalypt Plantations

Expansion of the nature conservation estate in northeastern New South Wales, Australia, has captured weed‐infested timber plantations amid a mosaic of high conservation value lands. We adopted a state‐and‐transition approach to test the hypothesis that restoration barriers restrict the natural regeneration of native species in Eucalyptus grandis plantations infested by Lantana camara in Bongil Bongil National Park, New South Wales. Plantation tree thinning and weed control were applied in factorial combination at three sites (totaling to 4.5 ha). Topsoil chemistry responses to these interventions were attributable to the “ash bed” effect, with temporary increases in topsoil pH_W and nitrate, particularly where canopy reduction was greatest. Other soil changes were minor, indicating that thinning and burning did not risk soil degradation. Plant species richness and functional group representation in the regenerating understorey were improved by the interventions. Regeneration of native potential canopy trees, understorey trees, shrubs and woody climbers, and perennial forbs all increased with canopy retention. Grass cover dominated the regeneration where canopy cover was less than 50%. In the absence of weed control, the cover of introduced shrubs increased with reduction in canopy cover, as did the rate of understorey regeneration generally. These responses indicate that thinning and weed control can reinstate succession, leading to structurally and compositionally diverse forest. Given the abundance of native woody regeneration under retained canopy, the lantana understorey was more important in inhibiting native regeneration. The experimental approach will promote efficient use of resources across the remaining 200 ha of low conservation value plantations in this national park.     

The potential impact of the trimorphic flea-beetle, <Emphasis Type="Italic">Alagoasa extrema</Emphasis>, on a selected weedy variety of <Emphasis Type="Italic">Lantana camara</Emphasis>

The potential impact of the larval feeding by Alagoasa extrema Jacoby (Coleoptera: Chrysomelidae: Alticinae) on potted plants of its host Lantana camara L. (Verbenaceae), a weed of major importance in South Africa, was examined. Under quarantine laboratory conditions, 2-month old plants of L. camara variety 029 White Pink were exposed to different larval feeding densities for a period of 18 days (completion of the larval stage). The above-ground dry mass of plants was significantly reduced following attack by larvae at densities of 5 larvae per plant (20% reduction) and 10 larvae per plant (28% reduction), when compared to unattacked plants. Attack by larvae over this short period had no significant impact on root growth. This demonstrates that A. extrema, once established in climatically favourable areas, could well augment other established agents in defoliating L. camara stands, reducing the accumulation of reserves and the competitiveness of the weed.     

黑果绣球胚的离体培养

通过不同发育时期黑果绣球(Viburnum lantana)胚的离体培养,找到了胚培养发芽率最高的取材时期,在北京地区是8月下旬到9月上旬。使用的基本培养基是MS培养基。使茎段分化的培养基是MS BA0.5 2ip5.0 zt0.5(单位mg/l下同。),培养40天后能得到大量的苗。切取带4片叶以上的苗,转接在大量元素减半的1/2MS IBA0.2的生根培养基土,10天以后开始生根。15天后经锻炼的小植株可移栽到瓦制花盆或营养钵中,盆土基质为1:3(体积比)的沙与草炭上的混合土,置于全光苗床(自然光照下,自控间歇喷雾保持叶面湿度。),室温18—25℃,生长10天就可以移入冷室,按一般植物管理。成活率80%以上。     

Geographical range and impact of five biocontrol agents established on Lantana camara in South Africa

A survey was conducted todetermine the present status of five biocontrolagents established on Lantana camara L.(Verbenaceae) in South Africa. Three ofthe five agents, Calycomyza lantanae(Frick), Ophiomyia lantanae Froggatt andTeleonemia scrupulosa Stål areestablished throughout the range of L.camara. The two hispine beetles, Octotomascabripennis Guérin-Ménevilleand Uroplata girardi Pic are restrictedto the warm, subtropical regions in the easternrange of the weed, and are unable to cope withthe plants becoming seasonally leafless in dryand temperate areas. The two beetles and T. scrupulosa are rated as the most damagingagents on L. camara. The impact of O. lantanae is uncertain, and due to lowpopulations, the impact of C. lantanae isnegligible. Insect populations typicallyaccumulate to maximise their impact on plantsby midsummer, giving plants the opportunity tocompensate for the cumulative agent damageaccrued at the end of the previous growingseason. A number of parasitoids were rearedfrom U. girardi, O. lantanae andC. lantanae, but only those adapted toC. lantanae are expected to significantlyreduce its field density. The agents feed anddevelop on a wide range of lantana varieties,and where two or more varieties co-exist,insects occurred in equal abundance on thedifferent varieties. The importance of varietalpreferences appears to have beenover-estimated, but needs consideration whennew candidates are evaluated. The impact ofthese biocontrol agents is insufficient toreduce L. camara to a manageablesituation, and additional candidates arenecessary to control this weed in South Africa.     

Unsuitability of Charidotis pygmaea for biocontrol of Lantana camara in Africa

The host range of the tortoise beetle,Charidotis pygmaea Klug (Coleoptera:Chrysomelidae), was studied under quarantinelaboratory conditions to evaluate the insect'ssuitability for release as a biological controlagent for the noxious weed, Lantanacamara L. (Verbenaceae) in South Africa.Culturing on the target plant, L. camara,proved problematic with high larvalmortalities. Host-specificity studies showedthat four species in the genus Lantana,and two species in the genus Lippiawere acceptable as host plants. Duringlarval development trials, the insect performedbetter on the indigenous Lantana rugosaThunb. (Verbenaceae) and the introduced,commercially used L. montevidensis(Spreng.) Briq. (Verbenaceae), than on any ofthe weedy South African L. camaravarieties tested. Adult multi-choice trialsindicated that the beetle preferred to ovipositon L. rugosa and L. montevidensis.It is therefore recommended that C.pygmaea not be released against L.camara in Africa.     

Acceptability and suitability of seven plant species for the mealybug Phenacoccus parvus

Survival, development and fecundity of cohorts of the mealybug Phenacoccus parvus Morrison were measured over one generation on seven plant species representing four plant families. Survival, development and fecundity were not significantly higher on the mealybug's principal field host, the weed Lantana camara L. (Verbenaceae), than on other plant species including Lycopersicon esculentum Miller (tomato) and Solanum melongena L. (eggplant). The acceptability of the leaves of the seven plant species to P. parvus first instar crawlers was measured on hatching, after active walking and after food deprivation. Lantana camara was the highest ranked plant species for all treatments. The number of crawlers settling on lower ranked plant species increased with the level of food deprivation.     

Review and Evaluation of Lantana Biocontrol Programs

This paper provides a review of lantana (Lantana camara L.) biological control programs worldwide. Tables on the origins of the agents introduced for the biocontrol of lantana, are presented, including references to the biology and/or host-tests for each species. Establishment and control rates of the introduced agents and cases leading to partial control of lantana are discussed. From the review, feeding groups and species contributing to control were identified. Leaf-, flower-, and fruit-feeding species were the most successful feeding groups, and the leaf-mining chrysomelid, Uroplata girardi Pic, was the most successful control agent. The main factor preventing establishment was the number of individuals released, while cultivar preferences, parasitism and predation, and climate reduced control. The implication of these results for lantana biocontrol programs is discussed, and future research requirements are identified.     

Effect of two biodegradable chelates on metals uptake,translocation and biochemical changes of Lantana Camara growing in fly ash amended soil

The present work had two purposes firstly to evaluate the potential of Lantana Camara for phytoextraction of heavy metals from fly ash amended soil and to assess the suitability of a proper biodegradable chelating agent for chelate assisted phytoextraction. Plants were grown in manure mixed soil amended with various concentration of fly ash. Two biodegradable chelating agents were added (EDDS and MGDA) in the same dose separately before maturation stage. Sampling was done at different growing stages. The plant took up metal in different plant parts in the following order: for Cu, and Zn leaf >root >stem, for Cr and Mn leaf>stem >root, for Ni root >leaf>stem and for Pb root≈leaf>stem respectively. For Cu, Zn, Cr and Mn Lantana camara acted as phytoextractor. Translocation factor and bioaccumulation coefficient was>1 signifying enrichment and translocation of metals in the plant. Morphological studies showed no toxicity symptom in the plant. Among biochemical parameters protein and nitrate reductase activity decreased, whereas, chlorophyll and peroxidise activity increased with the growth stages. Finally, it was evident from the results that Lantana Camara can be used as efficient phytoextractor of metals, with proper harvesting cycle and both chelate were proved as effective chelators for phytoextraction of metals.