Abstract:
Increased nitrogen applications to crops influence
plant-herbivore interactions and
potentially increase herbivore population growth.
In this research, the impact of nitrogen
fertilizations on nutritional quality of three cano
la (
Brassica napus
L.) cultivars (Zarfam,
Okapi and Modena), and, consequently, the performan
ce of mustard aphids,
Lipaphis
erysimi
Kalt., on them were investigated under green house
conditions. Nitrogen
fertilization treatments were 0, 75, 150, and 225 k
g N. ha
-1
. The results showed that
increased nitrogen fertilization resulted in enhanc
ing plant nitrogen content and
decreasing of C/N ratio of leaves. Based on N-conte
nt and C/N ratio, Zarfam had the
highest nutritional quality for herbivore among the
tested canola cultivars. Fertilization
generally increased the susceptibility of plants to
mustard aphid. Therefore, aphids
feeding on plants receiving higher nitrogen levels
had shorter nymphal developmental
time, longer adult longevity as well as greater fec
undity. The highest and the lowest values
of aphids’ intrinsic rate of increase (
r
m
) were calculated on Zarfam and Modena cultivars,
respectively. Moreover, nitrogen fertilization posi
tively affected
r
m
of aphids on all canola
cultivars. According to our results, management of
nitrogen fertilization and cultivation
of resistant cultivar could be suitable eco-friendl
y strategies to manage mustard aphid
population.
Keywords:
Life table parameters, Nitrogen fertilizer, Plant
resistance.
