تاثیر سطوح مختلف تنش خشکی در نهال های عناب بر پارامترهای رشد جمعیت سنک عناب Monosteira alticarinata (Hem.: Tingidae)

The jujube lace bug, Monosteira alticarinata (Hem.: Tingidae) is one of the important pests of jujube in South Khorasan province which has gained great economic importance in recent years. Some physiological parameters of jujube plant as well as life table parameters of M. alticarinata were evaluated under three water treatments (control, moderate and severe drought stress respectively equivalent to 1500 mL, 1125 mL and 750 mL of water per pot based on 100%, 75% and 50% field capacity of the soil used) using arenas consisting of jujube leaves inside Petri dishes. The results showed that leaf chlorophyll a, b, total chlorophyll and protein content were significantly higher in moderate water stress treatment than other treatments while the amount of total soluble solids, total carbohydrates, proline, organic carbon and C/N ratio were increased in drought stress. Water stress treatments had significant effects on all life table parameters of M. alticarinata. The lowest intrinsic rate of natural increase (rm) (0.128 ± 0.005), the finite rate of increase (λ) (1.136 ± 0.005), the net reproductive rate (R0) (440.32 ±160.065), gross rate reproduction (GRR) (470.22 ±212.25), total fecundity (76.83 ± 3.421), and the highest doubling time (DT) (5.39 ± 0.212) were measured on 750 mL irrigation per pot or severely drought stress treatment which indicates the negative effect of severe water stress on the life history characteristics of M. alticarinata. Although the well-watered treatment is assumed to provide the best conditions for population growth of M. alticarinata, due to shorter generation time, higher intrinsic rate of increase and finite rate of increase than water deficit stress ones, but the highest fecundity (150.72 ± 5.072), net (1985.34 ±578.92) and gross rate of reproduction (2107.72 ±767.109) was observed in case of those lace bugs fed on leaves come from intermediate water stress treatment which can be due to an increase on the chlorophyll, nitrogen, and protein contents of the jujube leaves in case of the moderate stress. Overall, this study revealed that the jujube lace bug like other sap feeders benefit from moderate water stress.