Articles

Insect fauna of canola and phenology of the diamondback moth, Plutella xylostella L. (Lepidoptera Plutellidae) as a key pest


Abstract


Canola or oilseed rape (Brassica napus L.) is one of the most important crops worldwide as a main source of edible vegetable oil. A field study of the insect fauna and the phenology of diamondback moth, Plutella xylostella L. in canola was conducted during the 2012/2013 and 2013/2014 growing seasons. The study was carried out at the Experimental farm, Faculty of Agriculture, Suez Canal University, Ismailia. A total of 31 insect species were recorded from the crop (13 pest species, 9 natural enemy species and 9 insect pollinators). Diamondback moth and cabbage aphid were the dominant pests, lady beetles and hoverflies were the most abundant natural enemies and honeybees were the dominant pollinators. The phenology, infestation rate and parasitism of P. xylostella were determined for the two growing seasons. In 2012/2013, the peak population (14.5 larvae or pupae/plant) was recorded in the eleventh week when temperatures ranged from 8.8 to 18.2 °C with relative humidity of 70%, while in the 2013/2014 season the peak population (8.3 larvae or pupae/plant) was recorded in the twelfth week when temperatures ranged from 8.2 to 20.0 °C with relative humidity of 70%. The infestation levels of Plutella xylostella ranged from 20 to 80% during the 2012/2013 season, while in the 2013/ 2014 season infestation levels ranged from 10 to 50%. Percent parasitism showed more at least two peaks in each growing seasons. Peaks were 44.5 and 31.2% in 2012/2013 season and 30.2, 32.6 and 25.9% in 2013/2014 season.


Keywords

Canola; Insect fauna; Plutella xylostella; Phenology; Infestation rate; Parasitism

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