جستجوی مقالات مرتبط با کلیدواژه « Life table » در نشریات گروه « گیاهپزشکی »

The life table parameters and predation rate of Typhlodromus bagdasarjani Wainstein & Arutunjan (Phytoseiidae) fed on Cenopalpus irani Dosse (Tenuipalpidae) nymphs reared on four apple cultivars Kohanz Golab, Imperial Gala, Lebanon Red, and Granny Smith were determined under laboratory conditions. The longest developmental time of immature stages in females was observed on Kohanz Golab, and the shortest one was on Granny Smith. The fecundity ranged from 19.17 eggs/female on Golab Kohanz to 32.78 eggs/female on Granny Smith. The highest and lowest intrinsic rate of increase (r) were obtained on Granny Smith (0.251 day-1), and Kohanz Golab (0.113 day-1), respectively. The total prey consumption by all immature stages on Kohanz Golab, Imperial Gala, Lebanon Red, and Granny Smith was 42.90, 34.71, 31.83, and 24.53 prey, respectively. The total prey consumption by adult females was 543.76 prey on Kohanz Golab, 419.40 prey on Imperial Gala, 376.87 prey on Lebanon Red, and 276.76 prey on Granny Smith. Our results showed that predator performance was strongly affected by feeding on C. irani mites reared on different apple cultivars, and also a significant difference was seen in the hunting capacity of T. bagdasarjani on different apple cultivars.

The melon aphid, Aphis gossypii Glover is one of the most important pests in pepper fields and greenhouses, which is of special economic importance due to its wide distribution and large host range. In this research, biological and reprodutive parameters of A.gossypii on two pepper cultivars (Poblano and Paprika) treated with salicylic acid, were investigated at laboratory conditions (25 ± 2 ˚C, 65 ± 5 % RH, and a photoperiod of 16L: 8D h). According to the results, the use of salicylic acid in both cultivars had a significant effect on most of the demographic parameters of the A.gossypii, compared to the control (spraying with distilled water) and decreased its life span, life cycle length, and Survival. The lowest and highest lifespan were 5.91 days (salicylic acid treatment in Paprika) and 10.25 days (control treatment in Poblano), respectively. Also, the use of this hormone had a significant effect on the reducing gross reproductive rate (GRR), net reproductive rate (R0), intrinsic rate of increase (r), and finite rate of increase (λ) of the aphid. The minimum and maximum values of r  were obtained in salicylic acid treatment on Paprika and control treatment on Poblano (0.2570 and 0.4046 d-1 respectively). So, salicylic acid can considerably reduce biological and reprodactive parameters of A.gossypii in pepper and can be used in integrated pest management programs of melon aphid.

The khapra beetle, Trogoderma granarium (Everts) is one of the most important insect pests of stored products, especially wheat grains, in Iran and some other countries of the world. In this research, effect of various wheat genotypes including Heidari, Aftab, Gaskojen, Kouhdasht, Tirgan, N-91-9, and N-92-19 was studied on biology and two-sex life table parameters of T. granarium under 33 ± 1°C, relative humidity of 65 ± 5%, and a photoperiod of 14:10 (L:D) h. Our results showed that the immature period of T. granarium was the longest on N-91-9, Heidari, and Aftab. The net reproductive rate (R0) ranged from 9.03 offspring on N-92-19 to 34.13 offspring on Gaskojen. The lowest intrinsic rate of increase (r) was for T. granarium reared on Heidari, Aftab, N-91-9 and N-92-19. The results of this study indicated that Heidari, Aftab, N-92-19 and N-91-9 were unfavorable genotypes for T. granarium development and population increase. These genotypes could be used as one of the sources of resistance in management programs of T. granarium.

The tomato leafminer moth, Tuta absoluta (Meyrick), is a key pest in greenhouses and tomato-growing regions in the world. In the present study, the lethal and sublethal (LC25) effects of two insecticides, thiocyclam hydrogen oxalate, and flubendiamide were evaluated on the life table parameters of T. absoluta under laboratory conditions. The leaf dipping was used for the bioassays. The life table data were analyzed based on the age-stage, two-sex life table theory. The results showed that thiocyclam hydrogen oxalate (LC50: 175.327 ppm) was more toxic than flubendiamide (LC50: 219.759 ppm) on the T. absoluta eggs. However, the sublethal concentrations of mentioned insecticides affected the life table parameters of T.absoluta significantly compared with the control, but flubendiamide prolonged the developmental time (embryonic, pre-adult, and pupal period) of T. absoluta, significantly more than thiocyclam hydrogen oxalate. Also, the population growth parameters such as intrinsic rate of increase, finite rate of increase, and net reproductive rate of insects treated by insecticides were lower than the control, significantly. The total results revealed that either thiocyclam hydrogen oxalate or flubendiamide have admissible lethal and sublethal effects on tomato leafminer eggs and can be considered in the integrated pest management program (IPM) of this pest.

Rice (Oryza sativa L.) is one of the most important cereal grains and serves as a staple food for nearly half of the world’s population. Trogoderma granarium Everts (Coleoptera: Dermestidae), commonly known as the Khapra beetle, is a significant pest that infests stored grains and other stored products in various countries worldwide, including Iran. The pest's polyphagous nature and high ability to survive for extended periods without food necessitate using chemical fumigants to control T. granarium in storage facilities. However, the serious adverse effects of these insecticides on humans and the environment render it imperative to explore alternative pest control approaches. One of the best safe options is using resistant cultivars in integrated pest management programs. Insect-plant interactions and the resistance of various cultivars to herbivorous insects can be studied by insects’ life history and population parameters.

The resistance and susceptibility of six commercial rice cultivars (Tisa, Khazar, Shafagh, Sadri, Nemat, and Hashemi) to T. granarium were determined by analyzing the life history and population growth parameters of the pest. The seeds of tested rice cultivars, which have a large cultivation area in Iran, were obtained from the Agricultural and Natural Resources Research Center (Gilan province, Iran). The initial colony of T. granarium was obtained from the laboratory of Department of Plant Protection, University of Mohaghegh Ardabili (Ardabil, Iran), and was reared in groups on wheat seeds (as the main host). The adult insects obtained from the primary colony were transferred to the seeds of tested rice cultivars (20 pairs on each cultivar), and were reared as a group for two generations. Then, the eggs (1-day-old) laid on each rice cultivar were used for the experiments. The beetle rearing and all experiments were carried out in a growth chamber set at 33 ± 1°C, 65 ± 5% RH, and 24 h darkness. Subsequently, the raw data obtained from the life history of T. granarium on various rice cultivars were analyzed with TWOSEX-MSChart software using an age-stage, two-sex life table model.

The study results indicated that immature survival rate on cultivar Sadri was higher than on the other tested cultivars. The incubation period was longer on cultivar Shafagh than on cultivars Sadri and Tisa. The shortest larval, pupal and the entire immature periods were observed on cultivars Sadri and Tisa, and longest on cultivar Khazar. The beetles raised on cultivar Khazar took approximately eight days longer to complete their development than those on cultivar Sadri. The fecundity of T. granarium (number of eggs laid by each female) on cultivars Sadri and Tisa was significantly higher than on cultivar Khazar. The longest oviposition period was observed on cultivars Sadri and Tisa, and the shortest on cultivar Khazar. The longevity of female and male adults was longest on cultivars Sadri and Tisa, and shortest on cultivar Khazar. The intrinsic rate of increase (r) was highest on cultivar Sadri and lowest on cultivars Hashemi, Shafagh, and Khazar. Additionally, the finite rate of increase (λ) was higher on cultivars Sadri and Tisa than on the other tested cultivars. The longest mean time generation was observed on cultivar Khazar and the shortest on cultivars Sadri and Tisa.

One of the reasons for the rapid development and high survival of T. granarium on cultivar Sadri may be the high protein content of its seeds, which has provided sufficient energy for the immature stages' rapid growth. However, the amount of protein and starch in cultivar Khazar is lower than in other cultivars, which may be a factor in this cultivar's resistance to T. granarium. Our results indicate that Sadri and Tisa are the most susceptible cultivars to potential population increase of the pest because the highest values of r and λ are on these two cultivars. However, owing to the highest values of r and λ on cultivars Hashemi, Shafagh, and Khazar, they are the most resistant cultivars to T. granarium. Consequently, resistant cultivars can be used in the genetic engineering of plants to minimize the damage caused by this key pest.

Aphis gossypii Glover is considered as the most important and damaging pest with wide host range and distribution on plants in fields and greenhouses. Common cotton aphid management in fields depends on the use of chemical insecticides in order to prevent economic damage. In the present study, lethal and sub-lethal concentrations of flonicamid and dichlorvos insecticides were assessed through bioassays and the effect of sub-lethal concentrations (LC10 and LC25) of each of them was investigated on life table parameters of cotton aphid on pinto beans under greenhouse conditions. Considering the contact effect of these insecticides, the insecticide spraying method was used on leaves containing aphids. According to the results, the female lifespan/longevity was significantly reduced by sub-lethal concentration, compared to the control and its lowest value (7.42 days) was recorded in LC25 concentration of flonicamid. The average number of nymphs produced per female aphid was significantly reduced in the treatments compared to the control. The highest and the lowest values of intrinsic rate of increase (r) were 0.38 per day in control and 0.21 per day in LC25 of flonicamid, respectively. A significant decrease was observed in sub-lethal concentrations of insecticides compared to the control in net reproductive rate (R0) and finite rate of increase (). The mean generation time (T) was significantly increased in flonicamid treatment compared to the control. Based on the findings of the present study, flonicamid had a better and more efficiency in controlling and reducing the population of aphids compared to dichlorvos.

In this study, the predatory mite Blattisocius mali was evaluated as a candidate predator for the biological control of fungus gnat, Lycoriella auripila in mushroom cultivation salons and greenhouses and its biological characteristics and population parameters were investigated under laboratory conditions at 25 °C, 70±5 % relative humidity and 16:8 h (L:D) photoperiod. The mean of the total pre-adult period in this experiment was 4.45 days and the lifespan of male and female adults was 18.45 and 20.46 days, respectively. The mean of the oviposition days was 13.88 days and the fecundity was 90.96 (eggs/female). Also, the predatory mite, B. mali feeding on the eggs of the L. auripila had a significant intrinsic rate of population increase (r) equal to 0.386 day-1 and its population increased about 44.551 times every 9.882 days. The results of this study showed the B. mali is a potential predator that can grow and reproduce and complete its life cycle fed on the eggs of L. auripila, successfully. Therefore, this predator can act as a suitable and safe biological control agent to reduce the fungus gnat population and be considered as a biological control agent in the integrated control of this pest.

Chemical control and biological control are an important part of integrated pest management (IPM). Insecticides affect the physiology or behavior of insects, posing risks to non-target organisms. The green lacewing, Chrysoperla carnea which is the best predator natural enemies to control pests on farms, orchards and forests of the country widely perceived to be in nature and play an important role in preventing the rapid proliferation of pests and shall have the vital balance The green lacewing most attention as a promising biological control agent released against pests in greenhouses, farms and gardens has attracted. In this study, the effects of sublethal doses of Primicarb, Imidacloprid and Oxydemetonmethyl against Chrysopa carnea Stephens (Neuroptera: Chrysopidae) were determined and compared. The results showed that these insecticides at LC30 had significant effect on the stable population parameters. Intrinsic rate of population increase (r) values for control‚ Primicarb, Imidacloprid and Oxydemetonmethyl were 0.142‚ 0.141‚ 0.140 and 0.134 (day-1), respectively. According to our results, there was significant differences in Imidacloprid and Oxydemetonmethyl rate of population increase (P≤0.5) compared to the control; also, three insecticides had significant effect on survival rate and life expectancy compared to control. These results provided that Primicarb had lower toxicity on C. carnea but theoretical basis for the rational use of Imidacloprid and Oxydemetonmethyl insecticides and the utilization and protection of C. carnea.

Liriomyza sativae Blanchard is considered as one of the most important pests of greenhouse and farm vegetables. According to the recommendation of using thiocyclam insecticide against the mentioned pest, in the present study the lethal and sub-lethal effects (LC10= 49.15, LC20= 87.1 and LC30= 131.5 a.i. mg/L) of thiocyclam insecticide (Evisect® SP50%) was evaluated on the biological parameters of this pest under laboratory conditions. The method used in the experiments was Leaf dip technique for leaves containing fly larva. Data analysis was performed using Age-stage two sex life table theory.  The results showed that adult lifespan/longevity was significantly reduced by sublethal concentration. Fecundity was also affected by the studied concentrations and the lowest amount of this parameter (34.23 eggs/female) was recorded in LC30 concentration. Accordingly, sublethal concentrations reduced the net reproductive rate (R0), and there were significant differences among the values of this parameter at all treatments tested when compared with control (control: 78.01, LC10: 63.76, LC20: 33.6 and LC30: 11.58 offspring/individual). Other parameters such as intrinsic rate of increase (r), finite rate of increase (l) were also significantly lower than the control. The highest estimated values for r and λ were recorded at control (0.19 and 1.21 day-1, respectively). Finally, with the reduced rate of development for individuals treated with sublethal concentrations, the mean generation time (T) was significantly higher in individuals exposed to any concentration tested, So that it was the lowest in the control with 22.49 days and the highest in LC30 with 26.25 days. The findings of the present research indicate that thiocyclam insecticide has a good potential in controlling the leaf miner in lethal and sublethal concentrations, and the importance of considering the role of sublethal effects when attempting to evaluate the total impacts of specific pesticide on an insect pest population and its natural enemy.

The cowpea weevil, Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae), a destructive insect pest of cowpea, Vigna unguiculata (L.), in the field and storage, causes significant losses in seed weight, germination ability, and the market value. The effect of cowpea (Mashhad cultivar) fertilization with chemical fertilizers (triple superphosphate (TSP) and urea) and some biofertilizers (Bradyrhizobium japonicum, Pseudomonas putida, mycorrhizal fungi) was studied on biology and life table parameters of C. maculatus at 28 ± 1°C, relative humidity of 65 ± 5%, and complete darkness. The highest immature survival (%) was on the grains treated with P. putida and control (97.75 and 95.69%, respectively), and the lowest survival was on the grains fertilized with TSP and B. japonicum (65.06 and 75%, respectively). Although the developmental time of C. maculatus reared on TSP- and B. japonicum-treated grains was longer than the control, the intrinsic rate of increase (0.124 day-1) and net reproductive rate (34.34 offspring) on the grains treated with TSP were lower than the control (0.143 day-1 and 51.07 offspring, respectively). Results of this research showed that the nutritional value of the grains obtained from TSP and B. japonicum treatments were lower than those obtained from other fertilizer treatments.

The predator mite, Amblyseius swirskii Athias and Henrioti, is one of the effective and polyphagous biological control agents that feed on different pest species such as thrips, whiteflies, and two spotted spider mites. Currently, it is used to control western flower thrips (WFT), Frankliniella occidentalis (Pergande), and some other insect pests but in times of outbreak and high density of the pest population, its efficiency is reduced and it is necessary to use complementary methods to control the pest damage. In this study, the effect of treated bell peppers (Lorca variety) with Jasmonic acid (0.5 mm), Trichoderma harzianum Rifai T22 (10 ml per plant from 107 spore/ml suspension), and the combination of Jasmonic acid with T. harzianum (JA + Th) was investigated on the biological characteristics and life table parameters of A. swirskii reared on WFT the. The experiment was carried out with 80 replications for each treatment in constant environmental conditions (25 ± 1°C, 65 ± 5% RH, and 16:8 h light: dark). Based on the results, the longest (9.41 days) and shortest (7.94 days) developmental time of immature stages were obtained in JA + Th treatment and control, respectively. The shortest female adult longevity (24.92 days) were also observed in JA + Th treatment. All the life table parameters showed a significant difference. The highest and lowest values of the intrinsic rate of increase (r), net reproductive rate (R0) and, finite rate of increase (λ) were estimated as 0.1688 and 0.1300 day–1, 24.49 and 11.71 (eggs/individual), and 1.184 and 1.139 day–1 for control and JA + Th treatment, respectively. The results of this study could be used in the application of A. swirskii with JA + Th treatment in integrated management programs of WFT..

Plants resistance against pests is one of the methods of replacing chemical pesticide that can keep the pest population below the economic injury level. Soil symbiotic bacteria can be useful factors in increasing the resistance of plants against herbivorous insects. The two treatments investigated in this research included the bean plant treated with bacteria and the bean plant without bacteria treatment as a control. The Vicia faba L. and black bean aphid were grown in a growth chamber at 25±4 0C, %50±5 RH and a photopriod of 14L: 10D hours. Then, 5 ml of bacterial suspension was added into the soil of sown mugs with a sterile syringe. These experiments on the effect of two treatments on faba bean showed that different treatments have a significant differences effect on the biological properties of black bean aphid. The highest developmental time (19.78±0.20 days) and the lowest fertility rate were occurred on P. polymyxa. There were significant differences between different treatments in terms of inherent rate of population increase (P≤0.5). The highest rate was occurred in control treatment (0.42±0.01 day-1) and the lowest in combination P. polymyxa (0.23±0.001 day-1). The life expectancy of black bean aphids, which was grown on P. polymyxa treated, was significantly lower than control. According to the results, it can be stated that faba bean plant treated can be effective in reducing the population of the aphids of the bean.

The Mediterranean flour moth, Ephestia kuehniella Zeller (Lepidoptera: Pyralidae), is one of the world’s most significant pests of stored products. E. kuehniella eggs and larvae are widely used in rearing parasitoids and predators for biological control programs. The purpose of this study was to look at the effects of various cereal hosts and cultivars, including wheat (Meraj, Paya and Aftab cultivars), barley (Oxin, Faraz and Fardan cultivars), rice (Hashemi cultivar), maize (704 Hybrid), sorghum (Spidfit cultivar), rye (Danko cultivar) and millet (Morvaridi cultivar) on life history variables, biological characteristics and population growth parameters of E. kuehniella. In addition, biochemical (protein and starch contents) and physical (humidity and hardiness index) characteristics of the cereal hosts were evaluated to understand any possible correlation between important demographic parameters and biochemical and biological features of the cereal hosts.

The E. kuehniella larvae were reared in a growth chamber at 26 ± 2°C, 60 ± 5% RH, and a photoperiod of 14:10 (L:D) hours on each cereal host. The duration of each stage, developmental period, and survival rate were observed and recorded daily. TWOSEX-MS Chart was used to analyze the life table parameters of E. kuehniella. The biochemical metabolites of cereals were measured using Bradford’s (1976) and Bernfeld’s (1955) methods.

Our findings showed that various kinds of cereal significantly impact the life history and demographical parameters of E. kuehniella. The millet host had the longest development time (66.57 days), while the rice and maize hosts had the shortest on Paya and Aftab cultivars. Total fecundity (mean number of eggs laid during the reproductive period) of E. kuehniella varied significantly depending on the hosts tested. The lowest fecundity values were observed on the millet host (49.10 ± 2.92 eggs), while the highest was on the maize host (136.18 ± 7.36 eggs). The maize host had the highest intrinsic rate of increase (0.067 day-1), and the millet host had the lowest (0.033 day-1) host. Significant differences in physical characteristics and biochemical metabolites were observed between the various hosts in this study. Furthermore, significant positive or negative associations were discovered between different hosts’ life history variables and humidity percentage, hardiness index, protein, and starch contents.

According to the findings, sorghum (Spidfit cultivar) and millet (Morvaridi cultivar) were the least suitable (relatively resistant) hosts for E. kuehniella growth. In contrast, wheat (Meraj cultivar) a

Brevicoryne brassicae is one of the most serious cabbage pests in the world. This pest feeds on the leaves, mostly on the host plant's middle leaves. Despite having many natural enemies, aphids are not entirely controlled by natural enemies due to their rapid reproduction. Applying chemical insecticides is one of the essential methods used to control aphids; using one pesticide to control several pests can reduce the costs and frequency of spraying. In this study, the lethal and sub-lethal effects (LC25) of matrine insecticide with a contact and stomach function on the cabbage aphid, were evaluated under laboratory conditions.

The dipping method was used in bioassay and life table studies against adults of aphid insects. The LC50 value of matrine insecticide for adults of cabbage aphid was 83.33 μl/ml after 24 hours, and LC25 concentration (30.11 ml/ml) was used to estimate the sub-lethal effects of matrine on the biological parameters of the cabbage aphid. Experiments were performed on the acephala variety of cabbage. One common method of investigating insecticides' non-lethal effects is demographic toxicology, which uses life table and growth population parameters to evaluate toxicity.

According to the results, the female lifespan/longevity and fertility affected by sub-lethal concentration were significantly reduced compared to the control (distilled water and citowett). The mean oviposition period of adult aphids decreased from 8.92 days in control to 3.79 days in LC25 concentration of the insecticide. The present study's data also showed that the sublethal concentration also affected the offspring of treated cabbage aphids. Accordingly, the sublethal concentration of matrine reduced the net reproductive rate (R0) from 23.96 nymphs per female in each generation in the control treatment to 3.26 nymphs in LC25. The intrinsic rate of increase (r) in sublethal concentration was recorded as 0.36 (day-1) and in control as 0.1 (day-1). Other parameters, such as finite rate of increase (l) and gross reproductive rate (GRR), were also significantly lower than the control. The mean generation time (T) of treatment affected by LC25 concentration of matrine increased compared to the control treatment.

Results of the current research in laboratory conditions showed that this insecticide has significant lethal and sublethal effects on the cabbage aphid. Therefore, matrine, as an herbal insecticide, can be considered in the management programs of cabbage aphids.

Adult insects of many parasitoids use carbohydrates to supply their energy. A high-carbohydrate diet increases the efficiency and other biological properties of parasitoids. Bracon hebetor Say (Hym: Braconidae) is one of the most important biological control factors on farms, orchards, and forests of the country, widely perceived to be found in nature, and can be effective in controlling larvae of leprose winged pests at an acceptable economic cost.

Materials and Methods:

 In this study, the effect of four sugar treatments [10% concentration of fructose, glucose, honey, and a mixture of fructose, glucose, and honey (1:1:1)] and distilled water (as a control for sugar treatments) was examined on the biological properties of B. hebetor male and female adults. B. hebetor was reared on fifth instars of Ephestia kuehniella Zeller (Lep: Pyralidae) in a growth chamber at 26±2 ºC‚ 60±5 %RH‚ and photoperiod of 16:8 (L: D) h. Daily observations and records were made for the development period and survival rate. The data were analyzed based on two-sex life table analysis using TWO SEX-MS Chart.

The present study showed a significant improvement in the biological reproductive and stable population parameters in sugar treatment groups compared with the distilled water treatment. The highest value of adult longevity and life expectancy (ex) of the B. hebetor occurred in fructose treatment. Moreover, the highest net reproduction rate(R0), finite rate of increase(λ), and lowest doubling time (DT) were observed in the mixed sugar treatment. On the other hand, the highest gross reproduction rate (GRR) and mean generation time (T) were found in glucose and fructose treatments. The results of study revealed that intrinsic rate of increase (rm) values for distilled water, fructose, glucose, honey, and mixed sugar were 0.257 ± 0.001, 0.272 ± .0011, 0.267 ± 0.033, 0.264 ± 0.007, and 0.291 ± 0.004 (day-1), respectively.

According to the results of the present study, B. hebetor was positively affected by the sugar treatments, and the suitability of sugar diets was ordered as mixed sugar > fructose > glucose and honey. In conclusion, sugar feeding is recommended for the mass rearing program of B. hebetor because suing them could increase the ability of this parasitoid in pest control. The highest rm value for the mixture of the three sugars indicated the importance of sugar-feeding quality in the mass-rearing program of natural enemies.