African
Journals Online
African Plant Protection
Volume 9, Issue 1, 2003
ABSTRACTS
Field
management of the banana weevil, Cosmopolites sordidus (Coleoptera:
Curculionidae), with Beauveria bassiana
Schoeman,
P.S.; Botha, H.
Abstract: A stem-baiting technique originally
used for the introduction of insecticides and entomopathogenic nematodes to
banana plants in Australia was evaluated in South Africa for the control of
banana weevil with Beauveria bassiana. Initially, no weevil control was
observed but, with subsequent applications, inoculum of the pathogen built up
sufficiently to provide effective control under field conditions. When adult
weevils were incubated in the laboratory even the control group showed signs of
mycosis, indicating effective transmission of the pathogen or migration of weevils
between plants and plots.
Keywords: Banana, Beauveria
bassiana, Cosmopolites sordidus, Microbial control
Revision
of the Afrotropical Ctenoplectrini (Hymenoptera: Apidae)
Eardley,
C.D.
Abstract: The Ctenoplectrini of the
Afrotropical Region comprise two genera, Ctenoplectra with six
pollen-collecting species, and Ctenoplectrina with two cleptoparasitic
species. Ctenoplectra appears to have specific food-plant requirements,
having been recorded only from Momordica balsamina and Momordica
foetida, two Cucurbitaceae species which secrete oil. A key to the genera
and species of the Ctenoplectrini is provided. New synonymies include the
following: Ctenoplectra nigrotestacea Magretti and Scrapter
lactipennis Friese are synonyms of Ctenoplectrina politula Cockerell;
Ctenoplectra fuscipes Friese, Scrapter abessinicus Friese and Ctenoplectra
fuscipes var. rufescens Cockerell are synonyms of Ctenoplectra
antinorii Gribodo; Ctenoplectra liberica Cockerell, Ctenoplectra
liberica ituriensis Cockerell and Ctenoplectra sjostedti Friese are
synonyms of Ctenoplectra polita (Strand); Ctenoplectra nitidula
Cockerell and Ctenoplectra rodhaini Cockerell are synonyms of Ctenoplectra
albolimbata Magretti; Ctenoplectra purpurea Cockerell is a synonym
of Ctenoplectra terminalis Smith; and Scrapter terminalis var. sculturatus
Strand and Scrapter sculpturata togoensis Strand are synonyms of Ctenoplectra
bequaerti Cockerell.
Keywords: Afrotropical bees,
Cleptoparasite, Ctenoplectra, Ctenoplectrina, Ctenoplectrini, Cucurbitaceae, Identification
key, Momordica, Pollinator
Polytrichinae, a new subfamily of Bdellidae (Acari:
Prostigmata) from the Afrotropical Region
Van der
Schyff, J.; Theron, P.D.; Ueckermann, E.A.
Abstract: A new subfamily of the Bdellidae,
Polytrichinae, with Polytrichus yemenensis as type genus and species, is
described and illustrated. This new subfamily is unique because the venter of
the hypostome bears eleven pairs of setae. A key to the subfamilies of the
family Bdellidae is provided.
Keywords: Acari, Bdellidae,
Polytrichinae subfam.n., Polytrichus yemenensis, Yemen
First
record of Riccardoella limacum (Schrank, 1776) and Riccardoella
oudemansi Thor, 1932 (Acari: Ereynetidae) from South Africa
Ueckermann,
E.A.; Tiedt, L.R.
Abstract: Riccardoella limacum and R.
oudemansi are recorded for the first time in South Africa from the brown
garden snail Helix aspersa and an unknown slug species, respectively.
The two mite species are compared morphologically using scanning electron
micrographs.
Keywords: Acari, Ereynetidae,
Molluscs, Riccardoella limacum, Riccardoella oudemansi, Slugs,
Snails, South Africa
Effect
of a mycorrhizal Glomus sp. on growth of plantain and on the development
of Radopholus similis under controlled conditions
Fogain,
R.; Njifenjou, S.
Abstract: Radopholus similis is one of
the most damaging nematodes of banana and plantain in Cameroon. Yield loss due
to this nematode on plantain can be more than 50% in case of severe
infestation. Arbuscular mycorrhizal fungi (AMF) have been shown to reduce
nematode populations in several plant species. Investigations were carried out
under controlled conditions to evaluate the effect of a Glomus sp.,
isolated from plantain in Cameroon, on plant growth and on nematode
infestation. Tissue-cultured plants were inoculated with the fungus during the
weaning phase. Nematode infestation was done six weeks after AMF infection.
Inoculation with the Glomus sp. significantly increased plant growth
parameters. Populations of R. similis were significantly lower on mycorrhizal
plants than on non-mycorrhizal ones. These preliminary results indicate that
the above Glomus sp. can be used to enhance growth of plantain plantlets
and as a potential biocontrol agent.
Keywords: Control,
Interactions, Nematodes, Musa, Mycorrhiza
Hoplolaimidae Filip'ev, 1934 (Nemata) from Rwandan banana fields31
Van den
Berg, E.; Marais, M.; Gaidashova, S.; Tiedt, L.R.
Abstract: During a survey of banana fields in
Rwanda, eight species of Hoplolaimidae were collected, viz. Helicotylenchus
dihystera (Cobb, 1893) Sher, 1961, Helicotylenchus egyptiensis
Tarjan, 1964, Helicotylenchus multicinctus (Cobb, 1893) Golden, 1956, Helicotylenchus
variocaudatus (Luc, 1960) Fortuner, 1984, Hoplolaimus pararobustus
(Schuurmans Stekhoven & Teunissen, 1938) Sher, 1963, Rotylenchulus
borealis Loof & Oostenbrink, 1962, Scutellonema cavenessi Sher,
1963, and Scutellonema paralabiatum Siddiqi & Sharma, 1994. Except
for H. multicinctus, seven are new records for the country.
Morphometrics, notes and illustrations are given for four species, H.
dihystera, H. egyptiensis, H. multicinctus and R. borealis, while H.
variocaudatus and S. paralabiatum are described in full. Helicotylenchus
affinis (Luc, 1960) Fortuner, 1984, is made a junior synonym of H.
variocaudatus while Rotylenchoides attenuatus Siddiqi, 1995, and Rotylenchoides
subterminalis Siddiqi, 1995, are transferred to the genus Helicotylenchus
Steiner, 1945.
Keywords: Descriptions, Helicotylenchus
variocaudatus, Hoplolaimidae, Rwanda, Scutellonema paralabiatum, SEM,
Taxonomy
Plant nematodes in South Africa. 5. Plant nematodes from
the Gouekrans area of the Swartberg Nature Reserve, with descriptions of one
new and one known Hemicycliophorinae (Nemata)
Van den
Berg, E.; Marais, M.; Tiedt, L.R.
Abstract: Nematodes found during a survey of
the Gouekrans area of the Swartberg Nature Reserve in 2000 are listed. Caloosia
exigua sp.n. is described and illustrated from Protea punctata.
Various specimens of Hemicycliophora demani Edward & Rai, 1971, are
described and illustrated. Hemicycliophora nullinca Van den Berg, 1987, Hemicycliophora
mangiferae Misra & Edward, 1971, and Hemicycliophora quercea
Mehta & Raski, 1984, are regarded as junior synonyms of H. demani.
Keywords: Caloosia,
Descriptions, Hemicycliophora, Plant nematodes, South Africa, Survey, Synonyms,
Taxonomy
Inheritance of grey leaf spot resistance in selected maize inbred lines
Wegary,
Dagne; Zelleke, Habtamu; Singh, H.; Husien, T.
Abstract: Grey leaf spot (GLS) caused by Cercospora
zeae-maydis has become one of the most significant yield-limiting diseases
of maize in Ethiopia. Evaluation and selection of local and exotic maize
genotypes by the National Maize Improvement Program of Ethiopia has resulted in
the identification of entries with fleck-type lesions (resistant reaction).
However, information on the inheritance of resistance in these entries is
lacking. The present study was undertaken to obtain information on the nature
of inheritance of resistance to GLS in maize inbred lines. Eight inbred lines with
contrasting reactions to GLS were crossed in a diallel mating system. The
resulting 28 F1s and eight inbred parents were evaluated in a
randomised complete block field experiment at Bako Research Centre in 2001.
Artificial inoculation with C. zeae-maydis was achieved by application
of dry, ground, infected leaves into the whorls of young maize plants. Data
were recorded on latent period, disease severity, disease incidence and lesion
type. Highly significant differences were observed among entries for all GLS
disease parameters studied. Mean squares due to general combining ability (GCA)
and specific combining ability (SCA) were highly significant for all disease
parameters. However, the magnitude of mean squares due to GCA was higher than
that of SCA for all the parameters, indicating the preponderance of additive
gene effects. The inbred parent CML-387 was the best general combiner for all
disease parameters, while estimates of GCA effects showed that the parental
lines A-7016, CML-197 and CML-202 tended to increase susceptibility to the
disease.
Keywords: Cercospora
zeae-maydis,
General combining ability, Grey leaf spot, Inheritance, Resistance, Specific
combining ability, Zea mays
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