Interaction between a South African population of xiphinema index and different grapevine rootstocks

CITATION: Malan, A. P. & Meyer, A. J. 1993. Interaction between a South African population of xiphinema index and different grapevine rootstocks. South African Journal of Enology & Viticulture, 14(1):11-15, doi:10.21548/14-1-2169.The original publication is available at http://www.journals.ac.za/index.php/sajevThirty-one grapevine rootstocks were used to test for reproduction, root feeding symptoms and transmission of grapevine fanleaf virus by a South African population of Xiphinema index. Grapevine fanleaf virus was transmitted within four months to the roots and systemically spread within six months to the leaves of all the rootstocks tested. No root damage and a low reproduction rate of X. index were found on the rootstocks Harmony, Freedom and 1613 C, all which have V. Longii and Othello in their parentage.http://www.journals.ac.za/index.php/sajev/article/view/2169Publisher's versio

Prospects for using entomopathogenic nematodes to control the vine mealybug, planococcus ficus, in south african vineyards

CITATION: Le Vieux, P. D. & Malan, A. P. 2015. Prospects for using entomopathogenic nematodes to control the vine mealybug, planococcus ficus, in south african vineyards. South African Journal of Enology & Viticulture, 36(1):59-70, doi:10.21548/36-1-937.The original publication is available at http://www.journals.ac.za/index.php/sajevIn South Africa, the most common method of mealybug control has been the use of chemical insecticides. Entomopathogenic nematodes (EPNs) of the of the families Heterorhabditidae and Steinernematidae potentially can be used within an integrated pest management scheme to control Planococcus ficus, the vine mealybug, which occurs on all parts of grapevine, including the roots. When Steinernema yirgalemense was applied to the soil of two vineyards with P. ficus, contained in pierced Eppendorf tubes, buried at a depth of 15 cm in the soil, mortalities of up to 50% were obtained after 48 h. The persistence of S. yirgalemense, measured using codling moth larval mortality was found to be zero in one vineyard, while in the other it was 70%, 12 weeks after application. Tests were conducted to establish the production of scavenger deterrent factors by H. zealandica and S. yirgalemense. Of the cadavers that were presented six days after nematode infection, 49% of the H. zealandica- and 60% of the S. yirgalemense-infected cadavers were left intact. Olfactometry tests indicated a significant difference concerning the number of S. yirgalemense infective juveniles (IJs) that were attracted to damaged Vitis vinifera roots and P. ficus, indicating active movement of the IJs and the attractive ability of organic compounds produced by the roots. This study shows that EPNs, and specifically S. yirgalemense, have promising potential as biological control agents for the control of P. ficus soil populations, and investigates some influential factors affecting EPNs as biocontrol agents in the agro-ecosystem.http://www.journals.ac.za/index.php/sajev/article/view/937Publisher's versio

Effect of humidity and a superabsorbent polymer formulation on the efficacy of Heterorhabditis zealandica (Rhabditida: Heterorhabditidae) to control codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae)

The original publication is available at http://www.tandfonline.com/toc/cbst20/current#.UrPeI7QgrZdAdequate moisture levels are required for nematode survival and subsequent efficacy as entomopathogens. Formulation of nematodes aimed at aboveground applications may assist in maintaining such moisture levels. In this study, we report the effects of a superabsorbent polymer formulation, Zeba® on the performance of an entomopathogenic nematode, Heterorhabditis zealandica Poinar, for controlling diapausing codling moth, Cydia pomonella (L.) larvae in cryptic habitats on trees. Water activity (aw-value) on bark was considered to be an indication of moisture levels on trees in cryptic habitats where codling moth larvae are known to occur, thereby influencing nematode efficacy. H. zealandica was only able to infect codling moth larvae at aw≥0.92, with aw50=0.94 and aw90=0.96.National Research Foundation, the Technology and Human Resources for Industry Programme and the South African Apple and Pear Producer's AssociationPost-prin

Cover crops with biofumigation properties for the suppression of plant-parasitic nematodes : a review

The original publication is available at http://www.sawislibrary.co.za/dbtw-wpd/textbase/sajev.htmPlant-parasitic nematodes are a problem in vineyards worldwide, with some species acting as vectors of grapevine soil-transmitted viruses. Global pressure on the use of soil-applied chemical nematicides has led to a search for new control options, or for alternative methods to suppress plant-parasitic nematodes as part of integrated pest management. This paper gives valuable background information on the use of cover crops with biofumigation properties for the suppression of plant-parasitic nematodes in vineyards.Winetech, Dried Fruit Technical Services and the National Research Foundation of South AfricaPublishers' Versio

Steinernema bertusi n. sp. (Rhabditida : Steinernematidae), a new entomopathogenic nematode from South Africa

Two isolates of Steinernema bertusi n. sp. were separately recovered from Tito, Mpumalanga, and Port Edward, Kwa Zulu Natal, South Africa. In this paper, we describe the isolates as a new entomopathogenic nematode (EPN) species using molecular and morphological methodologies. The new species belongs to the cameroonense -clade, which consists of nematodes only isolated from the African continent. Steinernema bertusi n. sp. is characterised by having the longest infective juvenile (IJ) for this clade at 716 (628-814) μ m. The IJ is further characterised by a body diam. of 32 (28-36) μ m and the pattern for the arrangement of the lateral ridges from head to tail is 2, 4, 5, 4, 2. The first-generation male spicule and gubernaculum length is 82 (72-88) μ m and 63 (54-72) μ m, respectively. Only 25% of the second-generation males possess a mucron. The first-generation females of S. bertusi n. sp. have a slightly protruding vulva, with double-flapped epiptygmata and a mucron at the posterior end. The new EPN species is most closely related to S. sacchari and is the sixth species to be included in the cameroonense -clade.https://brill.com/view/journals/nemy/nemy-overview.xmlhj2020Forestry and Agricultural Biotechnology Institute (FABI)Zoology and Entomolog

Steinernema fabii n. sp. (Rhabditida : Steinernematidae), a new entomopathogenic nematode from South Africa

A new species of entomopathogenic nematode, Steinernema fabii n. sp., was isolated by trapping with wax moth (Galleria mellonella) larvae from soil in an Acacia mearnsii plantation in the Mpumalanga province of South Africa. The new species is morphologically characterised by the length of the infective juvenile (IJ) of 641 (590-697) μm, by a tail length of 58 (52-64) μm, ratio a = 24 (21-41), H% = 53 (37-61) and E% = 93 (83-105). The pattern of the lateral field of the IJ of the new species is 2, 5, 2 ridges (3, 6, 3 incisures). The male of the first generation can be recognised by the long spicule of 90 (79-106) μm and gubernaculum of 66 (56-77) μm; D% = 64 (52-75) and GS% = 73 (63-86). The first generation female can be recognised by a protruding vulva, with a short double flapped epiptygmata and the lack of a postanal swelling, while the second generation differs with a post anal swelling and conical and sharply pointed tail. Analysis of DNA sequences for the ITS and D2D3 gene regions showed S. fabii n. sp. to differ from all other Steinernema species and to belong to a new monophyletic group, the ‘Cameroonian’ clade, consisting of S. cameroonense, S. nyetense, S. sacchari and S. fabii n. sp., all from the African continent. This group is closely related to species in the feltiaekraussei- oregonense Clade III.The Tree Protection Cooperative Programme (TPCP), the University of Pretoria and the National Research Foundation (NRF).http://booksandjournals.brillonline.com/content/journals/156854112018-02-28hb2016Forestry and Agricultural Biotechnology Institute (FABI)GeneticsZoology and Entomolog

The distribution, identity and virus vector potential of Xiphinema Spp. in the Western Cape Province

Dissertation (Ph. D. Agric.) -- University of Stellenbosch, 1995.One copy microfiche.Full text to be digitised and attached to bibliographic record

Differentiation of South African potato cyst nematodes (PCN) by analysis of the rDNA internal transcribed spacer region

The original publication is available at http://www.journals.co.za/WebZ/AdvancedQuery?sessionid=01-39372-1778849435.The original publication is available at http://www.sabinet.co.za/?page=Available-ePublicationsCysts from nematode-infested plots on eight potato farms in the Sandveld and Ceres regions of South Africa were analysed by means of rDNA-RFLP. The size of the PCR amplification products for all populations was typical for the genus Globodera. Restriction digestion of the amplified products with MspI and HinfI confirmed Globodera rostochiensisto be present in both the Sandveld and Ceres regions and Globodera pallidato be absent from South African potato cyst nematode populations. However, several populations from the Sandveld region showed no recognition of the HinfI restriction site and no digestion took place, indicating them to be a distinct Globodera species. Sequencing of the ITS1 region confirmed the presence of G. rostochiensis and an unknown Globodera species, and the absence of G. pallida in South Africa. Species-specific primers for the identification of G. rostochiensis and G. pallida were optimised.Publishers' Versio

Entomopathogenic nematodes (Steinernematidae and Heterorhabditidae) from the southwestern parts of South Africa

The original publication is available at http://www.sabinet.co.za/?page=Available-ePublicationsThe original publication is available at http://www.journals.co.za/WebZ/FETCH?sessionid=01-39552-1285830523&recno=9&resultset=2&format=F&next=ej/ej_nffull.html&bad=ej/ej_badfetch.html&&entitytoprecno=9&entitycurrecno=9.Soil samples were collected in the southwestern parts of South Africa to obtain entomopathogenic nematodes of the families Steinernematidae and Heterorhabditidae. In total, 498 samples were randomly taken from cultivated and uncultivated habitats, including deciduous fruit orchards, vineyards and natural vegetation. Entomopathogenic nematodes were isolated from 36 samples (7 %) by baiting with larvae of Galleria mellonella (greater wax moth). Heterorhabditis was the dominant genus isolated, while Steinernema was rare. The most common species was Heterorhabditis bacteriophora Other species identified were Heterorhabditis zealandica and Steinernema khoisanae. The isolation of H. zealandica represents a new record for South Africa, whereasS. khoisanae has thus far been recorded only from South Africa.Publishers' Versio

Potential of entomopathogenic nematodes for the control of the banded fruit weevil, Phlyctinus callosus (Schonherr) (Coleoptera: Curculionidae)

The original publication is available at http://journals.cambridge.org/action/displayJournal?jid=JHLEntomopathogenic nematodes (EPN) were evaluated for their potential use as biological control agents against Phlyctinus callosus, the banded fruit weevil (BFW). The susceptibility of larvae and adults to EPN was evaluated using 400 infective juveniles (IJ) per insect after 4 days in 24-well bioassay trays. The nematode isolates used were all able to infect BFW, although the larvae were found to be more susceptible than were the adults. The percentage mortality for BFW larvae ranged from 41 to 73% and for BFWadults from 13 to 45%. The most effective isolate, SF41 of Heterorhabditis zealandica, was used to investigate the effect of vertical movement of nematodes in sand and sandy loam soil, at specified concentration and temperature. A higher (82.2 ± 0.084%) percentage mortality rate was obtained with the sandy loam soil, than with the use of sand (67.5 ± 0.12%). The LD50 and LD90 values after 4 days of incubation were 96 and 278 IJ/50 µl, respectively. Nematodes were inactive below 15ºC, with the highest mortality of 74 ± 0.081% for BFW larvae recorded at 25ºC. Heterorhabditis zealandica was able to complete its life cycle successfully in sixth-instar BFW larvae after a period of 22 days. The study showed BFW larvae not to be as susceptible to nematode infection as they need a high concentration (400 IJ/larva) and 4 days to give effective control.Publishers' Versio