The effects of ecdysteroidal extracts of Matteuccia struthiopteris on demographic parameters of Plutella xylostella

Plant extracts، like phytoecdysteroids، are currently studied because of the possibility of their use in plant protection. There are several reports concerning the presence of ecdysteroid. But there is no report on possibility of ecdysteroidal compounds in Matteuccia struthiopteris (L.) (Onocleaceae). In this research، the effect of lethal and sublethal concentration of methanolic extract of M. struthiopteris was examined on Plutella xylostella (L.). Ecdysteroidal extracts of leaves from this plant were incorporated into food given to third instar larvae for two days. Then the larvae were reared on untreated leaves. Experiment was carried out at 27±1ºC¸ 65±5% RH and 16:8 (L: D) h. Compared to control، methanolic extracts fed at larval stage led to significant decrease in the percentage of pupation and adult emergence. The eggs from the emerging adults were picked up for demographic experiments. The rearing of the newly hatched larvae was continued individually on untreated leaves. Data analysis demonstrated that significant decrease in net reproductive rate (R0)، intrinsic rate of increase (rm) and finite rate of increase (λ). The highest values for rm and λ were 0. 19±0. 002 day-1 and 1. 21±0. 06 days، at 0. 69%، respectively. The present study demonstrated that mean generation time (T) and doubling time (DT) was increased significantly as concentration of the extract increased. These findings indicated that M. struthiopteris are effective for the control of P. xylostella. Therefore، this extract has potential to use as a reliable method in integrated management of this pest.