تاثیر همزمان کودهای نیتروژن، فسفر و سیلیکات سدیم روی پارامترهای تولید مثلی Aphis gossypii Glover (Hem: Aphididae) روی خیار

Aphis gossypii Glover (Hem: Aphididae) is one of the major pests of some vegetable plants in Iran. The experiments to evaluate the effects of simultaneous application of nutrient elements nitrogen, phosphorus and sodium silicate on reproductive and population growth parameters of A. gossypii in a randomized complete design with factorial arrangement of three factors including nitrogen in five levels (N1=0, N2=30, N3=60, N4=90 and N5=120 kg/ha), phosphor us in three levels (P1=0, P2=15 and P3=22.5 kg/ha) and sodium silicate in three levels (Si1=0, Si2=100 and Si3=200 kg/ha), a total of 45 treatments and nine replicates were performed. The experiments were conducted at temperature of 25±3°C, under 60±5% relative humidity (RH) and photoperiod of 16:8 h (light: dark). The results showed that the highest and lowest peak nymph generation rates were obtained on the N1P1Si2 and N4P3Si2, respectively, on day 19 of 0.8 and 0.66. The minimum and maximum nymphs produced by each female per day was 0.32 in N1P1Si2 and 0.95 in N2P1Si1, respectively. The lowest and highest gross fecundity rate and gross fertility rate were 24.83 and 69.99 in N3P2Si1 and N2P2Si1, respectively. The lowest and highest net fecundity rate and net fertility rate were 13.46 and 47.90 in N3P2Si1 and N2P3Si3, respectively. The minimum and maximum life expectancy on the first day of the emergence of adults in the tested treatments were 10.16 and 21.61 days, respectively, which were observed in the N3P2Si1 and N2P3Si3. Compare the biological parameters shown as increasing the phosphorus compared to nitrogen and sodium silicate has the greatest impact on growth parameters of this aphid.