فصلنامه تحقیقات حشره شناسی
سال دوم شماره 3 (پیاپی 7، پاییز 1389)

The cabbage aphid, Brevicoryne brassicae L. (Hem., Aphididae) is one of the most important pests of rapeseed and most other crucifera in many parts of the world. In this study, demographic parameters including life table, reproduction and population growth parameters of two populations of B. Brassica, collected from Shiraz and Gorgan, were studied. Experiments were conducted in laboratory conditions at 25±1ºC, 60±5% relative humidity and a photoperiod of 16:8 hours (L: D). Data were analyzed according to Jackknife method using SAS and MINITAB statistical softwares. The results indicated that, there was significant difference between mean preimaginal developmental time of aphid in two population of Shiraz and Gorgan (P<0.05). There was a significant difference between mean lifespan of aphid in two population of Shiraz and Gorgan. The life expectancy of newly emerged adults was 7.92 and 9.46 days in two populations of Shiraz and Gorgan, respectively. The gross fecundity rate in Shiraz population was higher than Gorgan population. There was a significant difference between gross fecundity rate in two population of Shiraz and Gorgan (P<0.01). The net reproduction rate was 9.22 and 7.54 females per female per generation in Shiraz and Gorgan population, respectively. The intrinsic rate of increase in two populations of Shiraz and Gorgan were 0.21 and 0.19 females/female/day, respectively. The finite rates of increase were obtained 1.23 and 1.21 days in Shiraz and Gorgan populations, respectively. The mean generation time of aphid was 10.58 and 10.48 days in two populations of Shiraz and Gorgan, respectively. The doubling time of aphid was 3.30 and 3.59 days in Shiraz and Gorgan populations, respectively.

One of the pests considered in Neishaboor s orchar is superfamily Eriophyoidea.These mites cause damage to leaves and branches and finally result in decrease in crops by creating gall, erineum and rust.However, The main damages of these mites around the world is more related to transmit of viruses from infected plants to healthy ones. It is considered necessary to recognize the mentioned superfamily and its species on fruit trees regarding to the fact that there is little information about these mites in Neishaboor. Therefore, samples are taken from different districts of Neishaboor during April 2008 till July 2009. The current study led to identify 5 mites species belonging to family Eriophyidae. Two species of them, marked with an asterisk (*) are reported for the first time from Iran and Khorasan Razavi Province.

The green lacewing, Chrysoperla lucasina is considered as a predator of the common pistachio psylla, Agonoscena pistaciae in the pistachio plantation areas of Rafsanjan, Iran. Some biological parameters of the green lacewing were examined under controlled conditions using three constant temperatures e.g., 25, 27.5 and 30ºC, and four prey diets e.g., 4th instar pistachio psyllid nymphs, eggs and 1st instar pistachio psyllid nymphs, cowpea aphid nymphs, Aphis craccivora and flour moth’s eggs, Sitotroga cerealella. The results showed that both temperature and diet regimes influence on preimaginal development and survival of the predatory lacewing significantly. Developmental periodof larvae were shortest while fed on either cowpea aphid nymphs or 4th instar pistachio psyllid nymphs and temperature of 30ºC. The weight of green lacewing cocoons were higher for those reared on 4th instar pistachio psyllid nymphs in larval stage. The larvae of C. lucasina fed on 1016, 4th instar psyllid nymphs and 315, 3rd instar cowpea aphids through the whole larval period at 30ºC. The preimaginal diets caused significant influence on fecundity and longevity of adult green lacewing. The reproduction potential of green lacewing was declined by increasing temperature through 22.5 to 32.5ºC severely.The intrinsic rate of natural increases (rm) of this insect was obtained 0.11 and 0.09 while it was reared using 4th instar pistachio psyllid nymphs and flour moth’s eggs at 25ºC through larval stage repectively.

Widespread use of chemical pesticides in agriculture production has brought up concerns regarding the accumulation of residues in food and agricultural environment and endangering human health and ecological balance. Cucumber is of a fresh use vegetable with high consumption in Iran and has more contamination due to short period between spraying and harvest time. This experiment were carried out to investigate the residues ofFenpropathrin (EC 10%), in a cucumber cultivar in greenhouse (Storm). Cucumber plants was sprayed at recommended doses (2 g/lit) and Samples were collected 1 hour, 1, 3, 5, 7 & 10 days intervals after treatment. Further purification achieved using a silica solid-phase extraction (SPE) cartridge and pesticides residues were analyzed using GC-MS. Result showed that Fenpropathrin levels below maximum residue level (0.5 mg/kg) weredetected 3 days after application and no residues were detected on the 10th day.

Economic Injury Level (EIL) of cotton bollworm Helicoverpa armigera Hb. was evaluated onSahel variety in Gorgan, Iran during 1999-2000. Infestation levels of 0, 2, 3, 4, 6 and 8 neonate larvae per 100 reproductive organs were studied in three generations of the pest by releasing them on cotton plants in the field. Statistically significant differences between treatments were observed in all generations. In the first generation, infestation level of 8%, in the second and third gernerations, infestation levels of 4, 6 and 8% caused significant reduction in yield (p0.05). Reduction yields for infestation level of 8% in the first-generation was 13.94%, in the second generation the infestation levels of 4, 6 and 8% were 9.8, 16.77 and 22% respectively, and in the same infestation levels in thethird generation were 8.25, 14.85 and 19.17%. Linear regression between the cotton yield and pestdensity was obtained in different generations. Considering the total cost of chemical cont rol operations and cost of yield, the economic injury level of the pest for the first, second and third generations were 1.19, 0.66 and 0.79 neonate larvae per 100 reproductive organs respectively, which is equal to 22.25, 15.77 and 21.33 neonate larvae per 100 cotton plants, respectively.

A faunestic survey were carried out on Pyralid moths (Lep., Pyraloidea) in Fasa & Jahrom cities inFars province of Iran during 2006-2007. Samples were captured by light traps. More than 290specimens (163 males, 133 females) were studied during this research and as a total, of 53 speciesbelonging to 41 genera, 10 subfamilies and 2 families were determined. Among them, Pyralid specieswere recorded as follows: Lamoria anella (Denis & Schiffermüller) Dattinia iranalis (Amsel)#Arenipses sabella (Hampson) and Iraniodes bilinealis (Amsel). Two Species of Arenipses sabella,Iraniodes bilinealis are reported for the first time from the Fars province.

Biology of citrus mealybug, Planococcus citri Risso (Hem., Coccidae) and its seasonal fluctuations were studied in citrus orchards in Mazandaran province, Iran, during 1996-1997. The pest has 3-4 generations and over-winters as eggs, 2nd and 3rd stages and adults on different citrus varieties and ornamental plants in the region of study. The shortest and longest developmental periods of one generation were 38 and 50 days, respectively. The mean numbers of eggs per female were 159, 229 and 171 in spring, summer and autumn, respectively. The mean life-span of males was 41.1 and 65.8and for females were 52.4 and 84.3 days at 20 and 25℃, respectively. The activity of over-wintering individual began at the end of April in both sprayed and unsprayed orchards. However, the peak of the mealybug population occurred in August and September in unsprayed orchards and in September and October in sprayed ones. The peak of population of natural enemies synchronized with the peak of the pest in unsprayed orchards. This synchronization might be a reason for reduction of the pest damage to fruit by 30%-40% in unsprayed orchards.

Ghorigul nursery located in East Azarbaijan province, Iran, is one of the most important nurseries for poplar seedling production. Three species of poplar trees including Populus alba, P. nigra and P. x. euramericana are planted in this nursery. Chaitophorus populi L., Pemphigus spirothecae Pass. and Camarotoscena sp. are among the important poplar pests of above mentioned poplars and cause direct and indirect damage to these trees. This study carried out based on evaluation of pest density on 15 poplar clones of Populus alba, P. nigra and P. x. euramericana in natural condition during 2006. In addition, antixenosic resistance of the mentioned clones for C. populi were investigated in laboratory during 2007. Field survey results indicated that only four clones were infested to P. spirothecae that among them P. nigra miandoab was the most susceptibile and most resistant and not infected clones were belonging to P. alba species. P. alba bostanabad, P. alba marand, P. alba mianeh and P. alba miandoab were susceptible to C. populi, respectively. Eight clones belonging to the species P. x. euramericana and P. nigra, were identified as completely resistant to C. populi. Laboratory survey on antixenosis resistance of poplar clones against Ch. populi revealed that the clones of P. nigra miandoab, P. alba miandoab, P. nigra maragheh, P. alba marand and P. alba mianeh were susceptible to the pest. Therefore, the results obtained from the laboratory were nearly similar to field investigation. In the study of susceptibility to Camarotoscena sp., all clones of P. nigra with the exception of Turkish clones were susceptible but clones belong to P. alba and P. x. euramericana showed the highest resistance to the pest.