جستجوی مقالات مرتبط با کلیدواژه « Demography » در نشریات گروه « کشاورزی »

The greenhouse whitefly, Trialeurodes vaporariorum Westwood, is one of the most destructive greenhouse pest in the world. In this study, the lethal and sublethal effects of Mentha piperita L. essential oil and its nanoformulation were investigated on the T. vaporariorum by considering the biological and population growth parameters. Extraction of essential oil was done by steam distillation using clevenger, and the chemical components of M. piperita were evaluated by gas chromatography-mass spectrometry. The results showed that monoterpenoids including carvone (%57.13) and limonene (%26.90) were the main characterized components of pipermint essential oil. The characterization of nanoformulation was done using dynamic light scattering (DLS), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The results showed that the nanoemolsion was spherical in shape with the average sizes of 179.74 nm. The leaf dipping was used for the bioassays. The bioassay results showed that, the nanoformulation of eesential oil (LC50: 3375.411 ppm) was more toxic than the pipermint (LC50: 4536.118 ppm) on the T. vaporariorum adults. The life table data were analyzed based on the age-stage, two-sex life table theory. Also, the sublethal concentration (LC25) of pipermint nanoformulation affected life table parameters of T. vaporariorum by prolonging the developmental time of T. vaporariorum, decreasing the female longevity and fecundity compared with essential oil. Also, the population growth parameters such as intrinsic rate of increase and finite rate of increase treated by nanoemolsion of essential oil (0.076±0.006 day -1) and (1.079±0.007 day -1) were lower than the essential oil (0.084±0.006 day -1) and (1.087±0.006 day -1), significantly. The total results showed that pipermint,s nanoformulation has the most lethal and sublethal effects on greenhouse whitefly compared with the pured form of essential oil which can be consider in integrated pest management program (IPM) of this pest.

Wheat (Triticum aestivum L.) is considered one of the most important food sources of the people of the world, so that about 18 percent of the calories and 19 percent of the protein needed by humans are supplied from this grain. The greenbug, Schizaphis graminum is one of the most important pests of wheat in many parts of the world, including Iran, which causes a significant damage to this crop annually. Pest pre-infestation and measuring demographic parameters is one of the most common methods to find out induced resistance in host plants. Due to the environmental and health consequences of excessive spraying of pesticides in wheat fields, use of "induced resistance" as a biorational method, has received a lot of attention in wheat integrated pest management in recent years. The main objectives of this study were to investigate the induced responses of three wheat varieties to S. graminum and also to find the most suitable pre-infestation period to activate this reaction in host varieties.

The seeds of three wheat varieties (Kohdasht, Morvarid and Aseman) were planted in growth chamber conditions (temperature of 25±2 Cº, relative humidity of 60±5% and a photoperiod of 14:10 L: D). After the plants reached the two-leaf stage, 5 one-day old female apterus aphids were placed on them and they were allowed to feed for 0, 2, 4, 6, and 8 days (the pre-infestation duration was considered as experimental treatment). After the desired pre-infestation duration, aphids were removed from the wheat plants and the plants were kept free of aphids for 48 hours. Then, the age-specific two-sex life table of aphid was made separately on the wheat plants corresponding to each variety and pre-infestation duration. 30 one-day-old first instar nymphs were used as a cohort and biological and demographic parameters of aphid were measured and compared using the paired bootstrap test.

Aseman variety had higher resistance to S. graminum compared to Morvarid and Kohdasht varieties, based on the values of demographic parameters. Due to aphid’s longer nymphal developmental time and mean generation time (T), shorter longevity and lower fecundity on Aseman variety, the intrinsic rate of increase (rm) on this variety (0.245 1/day) was significantly lower than Morvarid and Kohdasht varieties (0.348 and 0.358 1/day, respectively). In all varieties, pre-infestation to aphid reduced the values of biological and demographic parameters, but the effective pre-infestation duration was different according to the variety and studied parameter. With increasing pre-infestation duration from 0 to 8 days, the nymphal developmental time increased, while fecundity and the intrinsic rate of increase (rm) decreased significantly. In Aseman, Morvarid and Kohdasht varieties, the rm decreased from 0.245 to 0.187, from 0.348 to 0.275 and from 0.385 to 0.335 1/day, respectively, while pre-infestation duration increased from 0 to 8 days. In Aseman variety, which was relatively more resistant to S. graminum, the nymphal developmental time and the intrinsic rate increase (rm) changed significantly after a 2-days pre-infestation period, while aphid’s fecundity changed significantly after a 6-days pre-infestation duration. In Morvarid variety, nymphal developmental time, female fecundity and intrinsic rate of increase changed significantly after 6, 4 and 2-days pre-infestation durations, respectively. In all three varieties, intrinsic rate of increase (rm), as the most important demographic parameter, was changed significantly after a 2-days pre-infestation time.

The demographic response of S. graminum on the studied varieties was different and Aseman variety had higher relative resistance to wheat green aphid. In all three varieties, the pre-infestation of wheat plants with aphids led to induced resistance in them and reduced the biological and demographic potential of green aphid. Because of showing the appropriate induction reaction to S. graminum, planting Kohdasht (is recommended as a resistant variety to pathogenic fungi and suitable for cultivation in dry and semi-arid drylands) and Morvarid (a variety resistant to pathogenic fungi for planting in humid and plain areas) varieties can help to reduce the population of this aphid and increase wheat production in these areas. The results of this research can be useful in identifying resistance sources and mechanisms and implementation of integrated management of aphid in wheat fields of Iran.

 Demographic toxicology is usually the best way to evaluate total effects of pesticides on a population of natural enemy. Lethal and sublethal effects of imidacloprid, pymetrozine and Dayabon® were investigated on the sexual population of Lysiphlebus fabarum at laboratory conditions. Toxicity of the insecticides on immature stages of L. fabarum was evaluated, by dipping leaves containing parasitized Aphis fabae. These insecticides significantly reduced adult emergence rate when parasitized aphids were treated with field-recommended concentrations at larval stage. Imidacloprid had more toxicity than pymetrozine and Dayabon® at pupal stage. Imidacloprid was significantly more toxic than pymetrozine at adult stage. Dayabon® did not have residual effect on adults. In order to assess sublethal effects of three insecticides on life-table parameters of L. fabarum, the concentrations that had 25% mortality threshold and field-recommended concentrations were used for larval, adult and pupal stages treatments, respectively. Adults’ longevity, mean fecundity, females' oviposition period, sex ratio and some population parameters (r,λ, R0) were negatively affected by application of imidacloprid in comparison with other insecticides and control at larval, pupal and adult stages treatments. The intrinsic rate of increase (r) values for imidacloprid treatment and control at larval, pupal and adult stages of parasitoid were 0.2035 ± 0.01, 0.2240 ± 0.01 and 0.2273 ± 0.01 (day-1) and 0.2635 ± 0.01, 0.2759 ± 0.01 and 0.2687 ± 0.01 (day-1), respectively. According to obtained results, pymetrozine and Dayabon® could be used to control A. fabae in combination with L. fabarum.

Tuta absoluta (Meyrick) is the most important and destructive tomato pest in South and Central America, Europe and Iran, which has caused severe damage to greenhouses and tomato fields. In this study, the biological characteristics of this pest were studied on seven commercial tomato cultivars including Kimia Falat, CH Falat, Y Falat, Super Stone, Rio Grand, King Stone and Super 2270 inside the growth chamber set at 25±2°C, 65±5% RH and 16L:8D h. Damage of this pest was also examined in different tomato cultivars. The highest larval period was obtained on King Stone cultivar (11.98 days) and the lowest on Rio Grand cultivar (9.83 days). The lowest (5.48 days) and the highest (8.54 days) oviposition periods were observed on King Stone and Rio Grand cultivars, respectively. Female lifespan ranged from 7.83 days on King Stone to 11.54 days on Rio Grand. The lowest intrinsic rate of increase (r) (0.105 day-1) was observed on King Stone cultivar and the highest (0.158 day-1) on Rio Grand cultivar. The lowest values ​​of net reproduction rate (R0) and finite population growth rate (λ) on were recorded King Stone cultivar (25.54 offspring and 1.110 day-1, respectively) and the highest values ​​of these two parameters on Rio Grand cultivar (81.28 offspring and 1.172 day-1, respectively). The lowest number of mines and also the lowest percentage of infected leaflets were on King Stone cultivar (19.25 and 19.33%, respectively) and the highest values ​​of these parameters on Rio Grand cultivar (70.00 and 76.21%, respectively). According to the results of this study, King Stone cultivar is the most resistant and therefore it can be used in integrated management programs of T. absoluta.

The carob moth, Ectomyelois ceratoniae Zeller (Lep.: Pyralidae), is a polyphagous and destructive pest that causes considerable damage to various crops worldwide both before and after harvest. Host plant resistance is a critical component of integrated pest management and can be beneficial when used in conjunction with biological and chemical pest control approaches. The host type has a substantial effect on the biological characteristics and population growth parameters of E. ceratoniae. The purpose of this contribution is to evaluate the impact of eleven hosts, including peanut, apple, date, fig, olive, orange, pistachio, pomegranate, quince, and walnut, on the life history and nutritional indices of this pest.

The carob moth larvae were reared on each plant host in a growth room set at 30 ± 1 °C, 60 ± 5 % RH, plus a 14:10 (L:D) hour photoperiod. Daily observations and records were made of the duration of each stage, developmental period, and survival rate. TWO SEX-MSChart was used to evaluate the raw data based on the age-stage two-sex life table. Additionally, hosts' phytochemical metabolites were measured using a spectrophotometer. Correlations between demographic factors and nutritional properties with biochemical features of various hosts were then estimated.

The results indicated that various hosts substantially affected E. ceratoniae's demographic characteristics and nutritional indices. On walnut and artificial diets, the immature development period was the longest and shortest, respectively. Additionally, the intrinsic rate of increase (r) of E. ceratoniae was lowest on quince, orange, apple, olive, and highest on an artificial diet. Compared to larvae fed on other hosts, larvae reared on an artificial diet had the highest efficiency of conversion of ingested food (ECI) and efficiency of conversion of digested food (ECD). Furthermore, larvae-fed pistachio had a greater relative growth rate (RGR) than other tested hosts. The cluster analysis findings revealed that pomegranate and artificial diet treatments were relatively vulnerable hosts, whereas quince, orange, apple, and olive were the least suitable (most resistant) hosts for E. ceratoniae feeding. Significant variations in biochemical metabolites were observed between the various hosts in this study. Moreover, significant positive or negative associations between life history variables and nutritional indices plus biochemical features of various hosts were found. A significant negative correlation was observed between total phenolic content and total anthocyanin content of different hosts and E. ceratoniae fecundity, net reproductive rate (R0), intrinsic rate of increase (r), the efficiency of conversion of ingested food (ECI), and relative growth rate (RGR).

The findings may provide essential information for a better understanding of plant-herbivore interactions, which may aid in the development of effective integrated pest management (IPM) strategies for E. ceratoniae control.

Nabis pseudoferus is a major biocontrol agent of sucking pests and caterpillars. Life history parameters, consumption rate and cold storage of N. pseudoferus on three diets; Aphis gossypii, Ephestia kuehniella eggs, and Aphis gossypii + Ephestia kuehniella eggs were estimated at 25 ± 1°C temperature, 60 ± 10% R.H. and a photoperiod of 16:8 h. (L:D). The results revealed that the intrinsic rate of increase (r) were 0.033 ± 0.003, 0.043 ± 0.003 and 0.062 ± 0.002 day-1 which was significantly different in terms of feeding diets. Data analysis showed that the net predation rate (C0) of N. pseudoferus by feeding on cotton aphid and mixed diets of cotton aphid + Ephstia kuehniella eggs were 1347.95 ± 276.77 and 2259.62 ± 145.54, respectively. Additionally, hatching rate of N. pseudoferus eggs after cold storage at 5°C for 7, 14 and 21 days were 72.22, 69.23 and 69.23%, respectively. These results could be useful for optimizing rearing procedure of N. pseudoferus.

The stem borers, Sesamia spp. (Lepidoptera: Nocuidae) are the most important pest insects on sugarcane and maize in Iran. Biological control using its egg parasitoid wasp, Telenomus busseolae Gahan, is the main recommended controlling method for the pest. On the other hand, mass rearing of T. busseolae is strongly depended on mass rearing of its natural hosts. Current study was conducted to determine probability of mass rearing of Sesamia nonagrioides Lefèbvre using semi-artificial diet under laboratory conditions. The effect of a semi-artificial diet on life table parameters of the mentioned species in comparison with two natural diets, maize and sugarcane was studied under laboratory conditions. Life table construction and related parameters estimation were carried out using two-sex life table analysis procedure. According to the results, there was statistically difference among estimated values of the life table parameters among examined natural and semi-artificial diets. Total developmental period of S. nonagrioides were 53.51, 39.58, and 51.88 days on maize, sugarcane, and semi-artificial diets, respectively and there was no statistically significant difference between maize and semi-artificial diets. Estimated values for intrinsic rate of increase (r), as the most important life table parameter, were 0.0579, 0.09090and 0.0700d-1 on maize, sugarcane, and semi-artificial diet, respectively. Regarding intrinsic rate of increase, by statistically placing semi-artificial diet in the second group between two natural hosts of corn and sugarcane, its proper quality to meet the nutritional needs of the target species was confirmed. Considering all of the results and acceptable values of the life table parameters, examined semi-artificial diet is recommended for mass rearing of S. nonagrioides.

The predatory stink bug, Andrallus spinidens Fabricius, is a common natural enemy in Northern paddy fields of Iran. In the current study, life table parameters and consumption rate of A. spinidens fed on Plodia interpunctella Hübner larvae were determined under laboratory conditions. The evaluations were based on age-stage, two sex life table using TWOSEX and CONSUME-MSChart theories. According to obtained results, the total immature developmental times were 23.39±0.23 and 23.66±0.29 days for male and female, respectively. The adult pre-oviposition period (APOP) and total pre-oviposition period (TPOP) were evaluated to be 7.46±0.21 and 31.07±0.41 day, respectively. The intrinsic rate of increase (r), finite rate of increase (λ), net reproductive rate (R0), and mean generation time (T) were 0.136±0.004 day-1, 1.146±0.005 day-1, 188.52±26.61 offspring/individual and 38.54±0.49 day, respectively. The mean predation rate of total nymphal stage of the predator was 21.70±0.80 P. interpunctella larvae. Furthermore, the predation rate for female nymphs was significantly higher than male nymphal stage. Female and male adults of A. spinidens consumed 101.93±5.32 and 96.43±4.8 P. interpunctella larvae, respectively. In addition, the net predation rate (C0) of the total life span for A. spinidens was 104.32±6.22 P. interpunctella larvae per predator. The transformation rate (Qp) showed that A. spinidens consumed 0.55 P. interpunctella larvae to produce one viable egg. According to life table and predation parameters, it seems that the larvae of P. interpunctella might be a suitable intermediate prey for rearing this predator.

The effects of temperature on demographic parameters of the aphid parasitoid, Aphidius matricariae (Haliday), on lettuce aphid, Nasonovia ribisnigri Mosely, were studied at five constant temperatures, 15, 20, 22, 25 and 27 ± 1°C, 65 ± 5% RH and a photoperiod of 16L: 8D h. The life table parameters were estimated using age-stage, two-sex life table procedure. Moreover, the bootstrap method was used for estimating variance, mean and standard error of the population growth parameters, at studied temperatures. All estimated parameters were considerably affected by temperature. Accordingly, nymphs of N. ribisnigri could not settle and survive on the leaves at 27°C. Thus, mummies were not formed. Developmental time of the parasitoid wasp decreased with increasing temperature from 21.21 days at 15°C to 11.19 days at 25°C. The oviposition periods were 15.21±0.12, 9.47±0.10, 5.91±0.05 and 5.6±0.09 days at the temperatures of 15, 20, 22 and 25°C. Similarly, average number of mummies was 249.74±12.6, 192.72±12.8, 105.15±6.2 and 102.3±7.0, at the mentioned temperatures, respectively. The highest intrinsic rate of increase (r) and finite rate of increase (λ) were estimated to be 0.251 and 1.285 (d–1) at 20°C, respectively. However, there was no significant difference among the estimated values regarding intrinsic rate of increase and finite rate of increase at the temperatures of 20, 22 and 25°C. The highest value of net reproductive rate (R0) was 123.06 offspring/individual) at 15°C and the shortest mean generation time (T) was 13.98 (day) at 25°C. According to the obtained results, the temperatures 20-25°C, can be considered as optimal temperature range for the biological control of the currant lettuce aphid by using A. matricariae.

The life table and predation rate of Menochilus sexmaculatus (Fabricius) (Col.: Coccinellidae) was performed under laboratory conditions with 25±2°C and 27.5±2°C, respectively and 65±5 RH and 16:8 L:D. To study the life table, 60 larvae less than 24 hours were chosen and feeding on third and fourth instars of pomegranate green aphid Aphis punicae. Daily fertility, immature developmental time and mortality were analyzed through Age-stage, two-sex life table analysis-MSChart software. The mean and standard error of parameters of population growth were analyzed according to the bootstrap method. According to the results, the intrinsic rate of increase (rm), finite rate of increase, λ mean generation time (T0), Gross and net reproductive rate (R0) were 0.21±0.0085 d-1, 1.23±0.0104 d-1, 24.57±0.468 d, 236.366±33.57 and 178.148±27.83 eggs/individual, respectively. The amount of consumed aphids by fourth larval instars of ladybird were 188.08 for males and 179.09 for females. Average predation rate (C0) at pre-mature stage was 358.9 aphids and showed that predation has a high potential in natural population control of aphids.

The greenhouse whitefly, Trialeurodes vaporariorum Westwood (Hem.: Aleyrodidae) is a polyphagous and key pest that causes damaging to wide range of crops. The parasitoid wasp, Eretmocerus delhiensis Mani (Hym.: Aphelinidae) is a syn-ovigenic and thelytokous species that parasitizing greenhouse whitefly nymphs. In order to evaluation parasitoid wasp, Eretmocerus delhiensis Mani (Hym.: Aphelinidae) in control of greenhouse whitefly demography parameters of E. delhiensis on greenhouse whitefly on tomato cultivar Super-Chief at temperature 25±1°C, 65±5 % RH and a photoperiod 16:8 h (L: D) in growth chamber were studied. For calculation of population growth parameters Age- Stage, Two-Sex Life table was used. The result showed that oviposition period, longevity and fecundity for this parasitoid were 4.2±0.12 d, 20.74±0.5 d and 17.43±0.17 offspring respectively. Based on results of the life table, demography parameters consisting of net reproductive rate (R0), gross reproductive rate (GRR) were 12.11±0.94 and 31.43±1.85 offspring per female, intrinsic rate of increase (rm), finite rate of increase (λ), were 0.16±0.0059 d-1, 1.17±.007 d-1 and mean generation time (T) and doubling time (DT) of E. delhiensis were 15.66 d and 4.354/d respectively. Based on our results, this parasitoid is a promising candidate for greenhouse whitefly control.

The Mediteranean flour moth, Ephestia kuehniella Zeller (Lep.: Pyralidae) is a polyphagous pest in Iran. Effect of six wheat cultivars (Parsi, Pishtaz, Sardari, Bahar, Pishgam, Zarin) on demographic parameters of the E. kuehniella was determined at 26 ± 1 °C, 60 ± 5% RH and a photoperiod of 14:10 (L: D). The highest and lowest values of net fecundity and fertility rate were obtained on Bahar and Zarin wheat flour varieties, respectively. Also the highest and lowest values of intrinsic rate of increase obtained on Bahar (0.1076 ± 0.0018 female/female/day) and Pishtaz (0.0908 ± 0.0015 female/female/day) wheat flour varieties, respectively. The longest and shortest doubling time were observed on Pishtaz (7.58 ± 0.12) and Bahar (6.39 ± 0.10 days) cultivar, respectively. Because of the importance of population growth parameters, including intrinsic rate of increase (rm), Bahar was the most suitable host plants among the other wheat flour varieties. Determining of the suitable variety among different wheat flour would be helping us to improve natural enemy production using this pest as food on susceptible host plants.

Mealybug destroyer, Cryptolaemus montrouzieri Mulsant is the most important natural enemies of the citrus mealybug, Planococcus citri (Risso). Life table parameters of C. montrouzieri feeding on citrus mealybug, P. citri was studied at eight temperatures ranging 13 to 35 (±1) °C, 60 ± 10 % RH and a photoperiod of 16:8 (L:D) h. in growth chamber. Development of the coccinellid did not complete or laid eggs were infertile at temperatures 13, 15, 30, 33 and 35 °C. Therefore, life table parameters were estimated only in three temperatures, 20, 25 and 27°C. Construction of the life table and calculation of its parameters was conducted using Carey procedure. According to the results, the maximum and minimum values of the net reproductive rates (Ro) were 208.48 and 77.52 female/female/generation at 20 and 25°C, respectively. The values of finite rate of increase (λ) at the same temperatures were 1.04, 1.14, and 1.08 day-1, respectively. The maximum values of intrinsic rate of increase (rm) were 0.085 female / female / day and shortest mean generation time (T) was 57.37 days, at 27 °C. Estimated values for the doubling time (DT) were 15.56, 8.30 and 8.09 days at temperatures 20, 25 and 27°C, respectively. The results confirmed that temperature has a significant effect on population increase of the predatory coccinelid, C. montrouzieri and 27°C is the optimum temperature for population growth of C. montrouzieri among examined temperatures.