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URN: urn:nbn:de:hebis:26-opus-14286
URL: http://geb.uni-giessen.de/geb/volltexte/2004/1428/


Studies on the Mango-Ecosystem in Papua New Guinea with special reference to the ecology of Deanolis sublimbalis Snellen (Lepidoptera, Pyralidae) and to the biological control of Ceroplastes rubens Maskell (Homoptera, Coccidae)

Untersuchungen zum Mango-Ökosytem in Papua Neu Guinea unter besonderer Berücksichtigung der Biologie von Deanolis sublimbalis Snellen (Lepidoptera, Pyralidae) und der biologischen Bekämpfung von Ceroplastes rubens Maskell (Homoptera, Coccidae)

Krull, Stefan Magnus Eugen


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Universität Justus-Liebig-Universität Gießen
Institut: Institut für Phytopathologie und Angewandte Zoologie
Fachgebiet: Agrarwissenschaften, Ökotrophologie und Umweltmanagement fachübergreifend
DDC-Sachgruppe: Biowissenschaften, Biologie
Dokumentart: Dissertation
Sprache: Englisch
Tag der mündlichen Prüfung: 13.02.2004
Erstellungsjahr: 2004
Publikationsdatum: 02.03.2004
Kurzfassung auf Englisch: Studies on epigeal and arboreal and predatory arthropods in two mango orchards in the Central Province of Papua New Guinea

Predatory arthropods were studied by the beating method and pitfall trapping in two
mango orchards in the Central Province of Papua New Guinea (PNG). Both orchards
were not sprayed with synthetic insecticides during or before the study period.
Formicidae were the most numerous group within the epigeal and the arboreal arthropods
(2772 and 2269 ind., respectively). The weaver ant, Oecophylla smaragdina, was the
most abundant species within the arboreal arthropods. Pheidole spp. was most frequent in
pitfall traps. Spiders were the second most numerous group (524 and 619 ind.,
respectively). Lycosidae were predominant in pitfall traps and Salticidae in net catches
with the beating method on the trees. In the barber traps, Carabidae and Staphylinidae
were only present in low numbers (47 ind.). Coccinellidae were the most numerous
family within the arboreal predatory beetles (89 ind.). Telsimia sp. accounted for 63 % of
the ladybird beetles. Crickets were frequently collected in pitfall traps (187 ind.).

A survey on the occurrence and importance of mango pests in the Central Province of Papua New Guinea

A survey was conducted at four sites in the Central Province of Papua New Guinea to
determine the abundance and importance of nine insect pests in mango. The pests, except
fruit flies which were monitored by fallen fruits, were monitored three times during 2002
according to their occurrence within the mango season. Out of these pests, the white
mango scale Aulacaspis tubercularis, (Homopt., Diaspididae), the mango leafminer
Acrocerops spp. (Lep., Gracillariidae), the leafhoppers ,Idioscopus clypealis and ,I.
niveosparsus (Homopt., Cicadellidae), the soft scales Saissetia sp. and Parasaissetia sp.
(Homopt., Coccidae) and the fruit fly Bactrocera frauenfeldi (Dip., Tephritidae) proved
to be serious pests. Appropriate control measures, in particular biological and cultural
methods, are proposed. Infestation levels with fruit piercing moths Othreis fullonia, O.
materna, Eudocima salaminia (Lep., Noctuidae), aphids Toxoptera odinae (Homopt.,
Aphididae), blossom feeders Cosmostola sp., Gymnoscelis sp., Nanaguna breviuscula
(Lepidoptera) and planthoppers Colgaroides acuminata, Colgar sp., Scolypopa sp.
(Homopt., Flatidae, Ricaniidae) were lower. Appropriate control measures are
recommended but not immediately required.

On the biological control of Ceroplastes rubens (Homopt., Coccidae) with the introduced parasitoid Anicetus beneficus (Hym., Encyrtidae)

A study was conducted in three provinces of Papua New Guinea to determine damage by
the pink wax scale Ceroplastes rubens and to identify endemic parasitoids and
parasitization levels in order to evaluate the necessity and possibility of a classical
biological control with an introduced parasitoid. Infestation levels with the pink wax
scale variied 3.82 % and 6.40 %. The parasitization levels variied between 1.19 % and
3.05 %. Out of the nine endemic parasitoids identified, Aprostocetus sp. (Hym.,
Eulophidae) was the most frequent one. The pink wax scale parasitoid Anicetus beneficus
(Hym., Encyrtidae) was imported from Australia and released at four sites in the Central
Province in March/April 2002. The establishment was controlled at two sites six resp.
twelve months after release. Parasitization levels increased significantly (from 3.05 % to
5.45 % at Laloki and from 2.04 % to 22.15 % at Tahira). At both sites, A. beneficus was
the most frequent parasitoid. The parasitization process at the Laloki site was disturbed
by the ant Tapinoma sp.

Studies on the biology of Deanolis sublimbalis (Lep., Pyralidae) and its natural enemies

A study was conducted at four sites in the Central Province of Papua New Guinea to
determine infestation levels and biological behaviour of the red banded mango caterpillar
Deanolis sublimbalis (RBMC). Eggs and larvae were collected to identify natural
enemies and to develop potential control strategies. Infestation levels of mango fruits
variied between 3.36 % and 23.18 %. The eggs are mainly found at the peduncle covered
with dried sepals. Pupation takes place inside the bark of the mango tree. No other plants
than Mangifera spp. were confirmed as hosts in laboratory and field studies. The pest
goes into diapause during mango off-season. No egg or larval parasitoids were recorded.
Control measures like sticky bands are an appropriate method to prevent pupation in the
bark. A spraying scheme needs to be developed for commercial producers. It is further
recommended to search for potential natural enemies in the centre of origin of M. indica.