The relationship between ants (Hymenoptera: formicidae), vine mealybug (Hemiptera: pseudococcidae) and parasitoids in vineyards of the Western Cape Province, South Africa

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dc.contributor.advisorAddison, Piaen_ZA
dc.contributor.advisorPringle, K. L.en_ZA
dc.contributor.authorMgocheki, Nyembezien_ZA
dc.contributor.otherStellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology.
dc.date.accessioned2008-10-15T13:50:10Zen_ZA
dc.date.accessioned2010-06-01T08:22:56Z
dc.date.available2008-10-15T13:50:10Zen_ZA
dc.date.available2010-06-01T08:22:56Z
dc.date.issued2008-12en_ZA
dc.descriptionThesis (PhD (Conservation Ecology and Entomology))--Stellenbosch University, 2008.
dc.description.abstractThe mutual association between honeydew foraging ants and vine mealybugs in vineyards is detrimental to the biological control of the vine mealybug Planococcus ficus (Signoret). This study investigated the relationship between ants, vine mealybugs and their parasitoids to improve biological control of the vine mealybug. The investigation was carried out during two consecutive growing seasons (2005-2006 and 2006-2007) in two major wine grape growing areas of the Western Cape Province, Simondium (two farms) and Breede River Valley (one farm). A presence – absence cluster sampling system was used on a biweekly basis throughout both growing seasons from October to February on each of the farms. Additionally, yellow delta traps with vine mealybug pheromone, were used to catch parasitoids in vineyards. Prior to harvest, economic damage to grape bunches was assessed using a 0-3 damage rating index. Three ant species, Anoplolepis steingroeveri (Forel), Crematogaster peringueyi Emery and Linepithema humile (Mayr) foraged mainly on vine stems during both seasons, relative to other plant parts. Vine mealybugs of all stages were found on all sampling dates. Three species of primary parasitoids attacked the vine mealybug, including Anagyrus sp. near pseudococci (Girault), Coccidoxenoides perminutus (Timberlake) and Leptomastix dactylopii Howard. Bunch damage was significantly different between seasons in the Breede River Valley but not in Simondium. There was a negative linear relationship between ants and parasitoid activity in all vineyards. Spatial Analysis by Distance IndicEs (SADIE) was used to analyse spatial distribution of ants and parasitoids and ArcView, with its extension, Spatial Analyst, were used to map the gap, patch and local association indices where significant association and disassociation occurred. A significant association was found between C. peringueyi and parasitoids and L. humile and parasitoids. There was a significant disassociation between L. humile and C. peringueyi and between A. steingroeveri and C. peringueyi indicating interspecific hostility.en_ZA
dc.identifier.urihttp://hdl.handle.net/10019.1/1488
dc.language.isoenen_ZA
dc.publisherStellenbosch : Stellenbosch University
dc.rights.holderStellenbosch University
dc.subjectAntsen_ZA
dc.subjectVine mealybugsen_ZA
dc.subjectVineyards -- Western Capeen_ZA
dc.subjectPesticidesen_ZA
dc.subjectBiological controlen_ZA
dc.subjectDissertations -- Conservation ecology and entomologyen
dc.subjectTheses -- Conservation ecology and entomologyen
dc.titleThe relationship between ants (Hymenoptera: formicidae), vine mealybug (Hemiptera: pseudococcidae) and parasitoids in vineyards of the Western Cape Province, South Africaen_ZA
dc.typeThesisen_ZA
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Doctoral Degrees (Conservation Ecology and Entomology)