Anzeiger für Schädlingskunde, Pflanzenschutz, Umweltschutz (1996) 69, 136-139

R. Büchi (1996)
Eiablage des Rapsstengelrüßlers Ceutorhynchus napi Gyll., in Abhängigkeit der Stengellänge bei verschiedenen Rapssorten
[Egg-deposition of the stem weevil Ceutorhynchus napi Gyll. in relation to the stem length of different rape varieties]
Anzeiger für Schädlingskunde, Pflanzenschutz, Umweltschutz 69 (6), 136-139
Abstract: Eight trails with randomized block design with 4-8 rape varieties and 4-6 repetitions were performed from 1988-93 at two locations (Zurich-Reckenholz and Zollikofen). From each plot 10 plants were removed at one or two dates and the number of eggs and larvae of the stem weevil Ceutorhynchus napi were counted in the laboratory. In addition in 1991 and 1993 the number of splitted stems were recorded. The results show that C. napi neither prefers O-varieties nor OO-varieties for egg deposition. But there is a clear preference for a distinct developmental stage of the rape plants. The stem weevil prefers plants up to 22 cm hight for egg laying. On the average early vvarieties were significantly less infested by the stem weevil than moderately-early to late flowering varieties. The O-varieties Bienenu and Jet Neuf had fewer splitted stems than the OO-varieties and among them Idol and Eurol had fewer than Arabella and Libravo. The risk for splitted stems is increasing with higher infestation.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
(original language: German)
Link to article at publishers website

Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution
damage/losses/economics

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Ceutorhynchus napi	Rape/canola (Brassica napus)	Switzerland