The development, life history, reproduction, and population growth parameters of Planococcus citri Risso on coleus [Solenostemon scutellarioides (L.) Codd.] were studied at various temperatures ranging from 10 to 37ºC, 70±10% RH, and photoperiod length of 16: 8 h (L: D). Females and males successfully developed into adults at from 15 to 32ºC and 18 to 32ºC, respectively. All first instars died at 10, 12, and 37ºC. Lower temperatures (10, 12, and 15ºC) caused higher egg mortality than did higher temperatures (32, 35, and 37ºC). At all temperatures (except 15ºC), the highest percentage of nymphal mortality was observed in the first instar. The sex ratio was female-biased between 15 and 30ºC, but there was a slightly higher number of males at 32ºC. The highest adult longevities of females and males were obtained at 18 and 25°C, respectively. The pre-oviposition, oviposition, and post-oviposition periods were significantly different at various temperatures. The highest fecundity was observed at 23ºC. The shortest and longest oviposition periods occurred at 32 and 18ºC, respectively. Maximum values of the intrinsic rate of natural increase (rm), net reproduction rate (R0), and finite rate of increase (λ) and the shortest mean generation time (T) and doubling time (DT) were obtained at 25ºC. Our findings showed citrus mealybug performances to be highly affected by temperature

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Abstract:The experiment studied the effect of different nitrogen levels on the biology and life table parameters of the cotton aphid, Aphis gossypii Glover reared on Chrysanthemum indicum Kitan. The fertilizer treatments were administered at 0, 25, 50, 100 and 150% of the agronomic recommended concentration. The aphids were collected from greenhouses in Mahalat and transported to pots. The different nitrogen fertilizer levels did not show a specific effect on the potassium and phosphorus content in leaves. The intrinsic rate of increase and net reproductive rate ranged from 0.173 to 0.225, and 15.47 to 28.28, respectively, at different tested fertilizer levels. The aphids showed the significantly lowest mean generation time and the highest finite rate of increase when fed on chrysanthemum fertilized at a 150% fertilizer level. The aphids fecundity and survival showed a positive correlation when the fertilizer concentration was increased. On the other hand, the highest life expectancy was obtained for the aphids fed on chrysanthemum with a 25% nitrogen level. The present data suggest that plant nitrogen content is an important factor contributing to the increase severity of the cotton aphid as a pest of chrysanthemum.

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Due to importance and effectiveness of some entomopathogenic or insect parasitic nematodes in controlling of agricultural pests, or pests of non-agricultural plants, a study was conducted in order to identify the species of this group of nematodes in city of Tehran. As the result, three species belonging to the genus Oscheius were recovered in association with bark samples having the bark beetle galleries. Morphological and molecular data were provided for two recently recovered species of the genus, namely O. necromenus and O. onirici. Molecular data were also provided for a recently recovered isolate of O. tipulae. All three species were recovered in association with bark samples collected from dead trees in the city of Tehran. Morphological characters and morphometric data of the two aforementioned species are in accordance with the data given in their original descriptions. One recovered individual from a small bark sample characterized by its short body length was sequenced for its 28S and internal transcribed spacer (ITS) rDNA loci, and the results of BLAST search using the newly obtained partial sequences revealed that it belonged to O. tipulae. Molecular phylogenetic studies revealed recently sequenced Iranian populations of O. onirici and O. tipulae forming a clade with other isolates/populations of these species in ITS tree with maximal Bayesian posterior probability (BPP), and presently sequenced isolates of O. tipulae and O. necromenus form a clade with other isolates of these species in 28S tree. The two species O. onirici and O. necromenus were reported in Iran for the first time.