Document Type : Agricultural Entomology
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Abstract
The false chinch bug, Nysius cymoides, has threatened canola plantation since a crowd of bugs swarming out into the adjacent fields upon the plant harvesting. In order to study its biology and demography under laboratory conditions (T = 24 ± 1ºC; R.H. = 60-70% and
L:D = 16:8 h), individuals from a colony originated from Nowzarabad (Neka, Mazandaran province) were used. Newly laid eggs were placed in small petri dishes (6 × 1 cm) and provided with water and canola seeds (Option variety) till adulthood. Nine pairs of adults were separately confined in 0.3 l transparent plastic containers. Every day, they were provided with water and rape seed, and monitored to check hatching, moulting, mortality and oviposition. Results showed that incubation period and five nymphal stadia were: 8.11 ± 0.07, 8.36 ± 0.25, 5.31 ± 0.18, 5.95 ± 0.48, 5.53 ± 0.41 and 6.83 ± 0.51 days, respectively. Total developmental times of the immature stages of females (37.00 ± 1.55 days) and males (36.89 ± 1.24 days) were not significantly different. Among nymphal stages, first instars had the highest mortality. The bug could produce many continuous generations without entering diapause under the studied conditions. Preoviposition period was 4.0 ± 0.29 days. Gross, GRR, and net reproductive rates, Ro, were 126.17 and 32.86 female eggs, respectively. Other demographic parameters such as intrinsic rate of increase, rm, finite rate of increase, λ, generation time, T, and doubling time, DT, were: 0.07172 and 1.07436 (female/female/day), and 48.69 and 9.66 days, respectively
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