جستجوی مقالات مرتبط با کلیدواژه "فراسنجه های زیستی" در نشریات گروه "گیاهپزشکی"

The striped bug, Graphosoma lineatum L. is one of the pests of Apiaceae family such as parsley, carrot, celery and some medicinally important plants. The adults and nymphs of this insect feed on seeds of host plants. The eggs of the striped bug have an important role in mass rearing program of some parasitoids. Nutritional supplements undertake an essential function in mass rearing of insects and increase the efficiency of production. Vitamins such as B group have different functions in physiology of insects. The growth and development of insects hinge on acquiring essential nutrients through food materials. Apart from their primary food source, insects rely on essential amino acids and certain minerals for proper nutrition. These crucial components must be obtained from their food sources. Symptoms of nutritional deficiency, as reported in various research studies, include delayed growth, weight loss, prolonged immature stages, increased mortality, wing deformities, alterations in mating behaviors, and various physiological issues. In this study the effects of some vitamins and amino acids on anatomy of salivary glands, total protein of body, developmental time and fecundity of G. lineatum were evaluated in controlled conditions.

Insects reared on parsley seeds adhered on the inner side of big plastic containers in controlled condition. Supplements including vitamins B12, B6, B1 and Serine and Phenylalanine amino acids selected for evaluation. These supplements used for the treatmnet of G. lineatum in four different concentrations dissolved in water. For evaluating the effects of nutritional supplements on anatomy of salivary glands, both glands separate after dissection of adult’s thorax, and dimension of glands including width and length of posterior and anterior lobs, measured by micrometer apparatus located on stereomicroscope. Total body protein measured by Kjeldahl apparatus after well drying the total body of insects in oven followed by fine powder of dry materials. Total protein was determined using a standard method, calculated by multiplying the nitrogen amounts by 6.38, a constant value. In distinct experiments, the impact of nutritional supplements on the duration of each nymphal stage was investigated. One-day-old eggs were employed for this purpose. Following treatment justification, the time required for the development of each instar was recorded on a daily basis. All tests were replicated three times, with distilled water used for the control treatment. The data were analyzed by One-way ANOVA experimental randomized design and Duncan’s multiple range test using SAS software used for comparing the means.

The results disclosed a significant impact of all vitamins and amino acids on all studied parameters. Notably, in the case of salivary glands, the posterior lobe exhibited a more pronounced effect in insects fed with B1, B6, and Phenylalanine. Different concentrations of vitamin B6, B1 and Phenylalanine affected total protein content of male and female insect’s body. Vitamin B12 had non-significant effect on male and female total body protein. Nutritional supplements changed the rate of laid and hatched eggs in addition with nymph’s developmental time. Vitamin B12 in the concentration of 0.005 g/l, B6 in the concentration of 0.25 g/l, B1 in the concentration of 0.5 g/l, Serine and Phenylalanine both in the concentration of 0.5 g/l showed the highest rate of laid and hatched eggs. Vitamin B6 and B1 in the concentration of 1 and 1.5 g/l resulted in prolonging the nymph’s life span in comparing with controls. The negative effects of high concentrations of nutritional supplements on fecundity and normal developmental period of nymphs well documented in this study. Metabolism, cell division, hormone synthesis, enzymes activity and many physiological parameters affects by supplements especially vitamins. Any disorder in utilization, absorption and inhibition of their function leads to biological and behavioral problems in insects. In some cases, the function of symbionts for compensation essential supplements documented.   

The results of this study indicate important function of vitamins B12, B6 and B1 on G. lineatum nymphal developmental period. In high concentrations, rate of growth decreased in comparison with controls. Salivary glands anatomy showed some changes in dimensions especially in posterior lobs in dose-depending manner. Number of eggs laid and hatched decreased especially in high concentrations of nutritional supplements. The results of this study will help to justify better meridic diet for rearing striped bug. In semi-artificial diets for rearing this insect, corporation of little concentrations (optimum) will improve the fitness of insects.

Background and Objectives Tetranychus urticae, as the two-spotted spider mite, is considered as one of the most important and destructive herbivorous mites in farms and greenhouses, which is very important to control due to its wide host range. The damage caused by agricultural pests combined with the harmful effects of synthetic chemicals used in their control can be mitigated or eliminated by using botanicals, which are derived from renewable resources including a mixture of various bioactive ingredients. Therefore, finding a suitable alternative way for controlling this pest is necessary by considering the resistance to acaricides, as well as undesirable effects of chemical compounds. The present work aims to evaluate microcapsule essential oil of Mentha piperita and its lethal and sublethal toxicity to T. urticae. Materials and Methods Laboratory bioassays were used for evaluating the sublethal effects of peppermint essential oil microcapsules on biological and population parameters of T. urticae. The life table parameters of T. urticae were conducted on leaf discs under laboratory conditions at 25 ± 2°C, 60 ± 5% relative humidity, and a photoperiod of 16:8 (L: D) hours. Then, the duration of each stage, developmental time, and survival were observed and recorded daily. In addition, the raw data were analyzed based on age stage two-sex life table theory with MS-Chart. Results Based on the results, microcapsules of Menthe piperita caused a significant reduction in fecundity and longevity. Those treated with LC20 and LC30 had a significant reduction at net reproductive rate, compared to those treated with LC10 and untreated ones. The intrinsic and finite rate of increase reduced significantly in higher concentration compared to the control. In addition, the mean generation time decreased significantly at the upper dose, compared with LC10. Discussion Botanic acaricides can be used for controlling Tetranychus urticae, and the microencapsulated formulation of these products makes them more stable. Familiarity with the chemical nature of the bio-active pesticide/acaricidal compound can be considered in future research which can play a role in developing an effective and environmentally friendly treatment against spider mites, leading to a decrease in reliance on synthetic pesticides/acaricides. The results of this study can be used in designing the mentioned pest management programs by considering the detrimental effects of M. piperita essential oil microcapsule on some biological parameters of T. urticae.

Background and Objectives The lacewings are predatory insects which are widely used in biological control programs. Meanwhile, the green lacewing, Chrysoperla carnea Stephens (Neuroptera: Chrysopidae), has attracted considerable attention as a promising biological control agent for greenhouse and field pests. Green lacewing is considered as an important bio-control agent due to its geographical distribution, broad host range, potency of suitable compatibility in agro-ecosystems, high searching ability, easy mass rearing in laboratory, high reproductive potential and broad resistance to numerous insecticides especially in larval and pupa stages. In this regard, it is highly important to reduce the consumption of the conventional pesticides which are compatible with predators and have low negative effects on beneficial organisms. In addition, life tables should be highlighted as the most reliable and effective technique for assessing the fitness of a population. Among the methods for selecting suitable pesticides in integrated pest management (IPM) programs, evaluating all of its effects on the different biological parameters of both sexes is the prime tool for population ecology studies. Materials and Methods Laboratory bioassays were investigated to evaluate the sub-lethal effects (LC30) of thiamtoxam, imidacloprid, and acetamiprid on biological characters and population parameters of C. carnea. The sub-lethal effects of thiamtoxam, imidacloprid, and acetamiprid on the demographic parameters of green lacewing were evaluated in vitro at 25±2° C, relative humidity of 65±5%, and light period of 8:16 h (light: dark). The raw data were analyzed based on two-sex life table analysis. Results All sub-lethal concentrations caused a significant decrease in oviposition period, total fecundity, longevity, and total life span in comparison to the control. Maximum and minimum mean lifespans of C. carnea individuals were observed in the untreated group and LC30 concentration of thiamtoxam. Total fecundity varied from 208.7 (offspring/individual) in treatment with LC30 thiamtoxam to 302.3 (offspring/individual) in the control treatment. The intrinsic and finite rates of increase (r, λ) were not affected by the imidacloprid concentration. The net reproduction rate (R0) reached its lowest level (141.1 offspring /individual) in acetamiprid treatment. Discussion The adaptability of pesticides with biological agents is one of the major concerns of IPM practitioners. Hence, it is essential to have necessary information about the action mode of pesticides on non-target insects. Furthermore, finding efficient biological control agents is considered as the first step in developing biological control programs. Therefore, the effects of sublethal concentrations of thiamtoxam, imidacloprid, and acetamiprid in combination with C. carnea were discussed in order to design integrated management programs.

Habrobracon hebetor Say, is one of the most important larval parasitoids of many lepidopteran pests, particularly the family Noctuidae. In this study, the lethal and sub-lethal effects of chromafenozide, pyridalyl and thiodicarb, as insecticides, were investigated on this parasitoid under laboratory conditions. Bioassay tests on adults were conducted based on contact method and sub-lethal effects were done based on demographic toxicology. According to bioassay tests, estimated LC30 values for chromafenozide and thiodicarb were 126.43 and 54.24 mg a.i./L, respectively. Since even with the application of three times more than that of the field concentration of pyridalyl (2250 mg a.i./L), maximum mortality percentage of insects was 19%; LC30 value was not estimated for this insecticide. In order to assess sub-lethal effects of insecticides, female wasps were exposed LC30 values of chromafenozide and thiodicard and the field concentration of pyridalyl (750 mg a.i./L). According to sub-lethal tests, insecticide treatments significantly affected duration of life different, fecundity and life table parameters. The intrinsic (r) and finite (λ) rates of increase were significantly lower in insecticide treatments than that of control. Overall, results showed that thiodicarb had the highest toxicity effect on H. hebetor, while pyridalyl and chromafenozide had less adverse effects on this parasitoid. Following field experiments and subject to confirmation of the results of this study, it is possible to use pyridalil and chromafenozide in integrated pest management programs.

Macrolophus pygmaeus Rambur is an most omnivorous predator which has considered in integrated pest management programs, especially for greenhouse pest management. In this study, biological properties and life table statistics of M. pygmaeus by feeding on Artemia urmiana Gunther cysts and Ephestia kuehniella Zeller eggs were studied under laboratory conditions (25±1°C, 65±5 % relative humidity and 16:8h L: D photoperiod) with 60 replications. The pods of green bean Phaseoulus vulgaris L. served as oviposition substrate and the moisture source. Developmental time of nymphal stages which fed by of E. kuehniella eggs and Artemia cysts were 17.04±0.11, 18.06±0.18 d for males and 17.31±0.09, 18.17±0.15 d for females respectively and were significantly different as well as intrinsic rate of increase (rm) was 0.080±0.005 and 0.064±0.006 d–1 respectively. Also, net reproductive rate (R0) was 18.12±2.97 and 10.70±2.43 eggs/individual on those food regims respectively. Furthermore, mean generation time (T) was estimated as 35.93±0.33 and 36.66±0.53 d respectively. Meanwhile, the reproductive parameters on flour moth larvae have been significantly higher than Artemia cyst. The results showed that feeding on E. kuehniella reduces nymphal period, while increases productivity and longevity of adults. According to the present findings, E. kuehniella is more suitable prey for rearing of this predator, but in absence of access to E. kuehniella, rearing on Artemia cysts is also possible.

The carob moth Ectomyelois ceratoniae (Lep.: Pyralidae) is the most important pest of pomegranate in Iran which annually causes considerable damages. Trichogramma wasps are one of the main factors in biological control of this pest, which can be used effectively to reduce damage. In this research, biological parameters of three species ofTrichogrammatids viz. T. brassicae, T. emryophagum and T. pintoi were evaluated on the carob moth, (E. ceratoniae) eggs under the laboratory conditions. The results showed that reproductive period, post-reproductive period and adult life span for T. brassicae reared on the carob moth were 7.8, 0.9, 8.7 days, respectively. These parameters for T. embryophagum were 8.2, 1.00, 9.2 days and for T. pintoi were 7.4, 1.1, 8.5 days, respectively. The studied species lacked pre-reproductive period. The results also showed that gross reproductive rate (GRR), intrinsic rate of natural increase (rm), mean generation time (T) and finite rate of population increase (λ) for T. brassicae reared on the carob moth were 38.021 (eggs), 0.286 (day-1), 12.659 (days), 1.330(day-1), respectively. The above calculated parameters for T. embryophagum reared on the same host were 39.247 (eggs), 0.311 (day-1), 11.659 (days), and 1.365 (day-1), and for T. pintoi they were 28.626 (eggs), 0.262 (day-1), 12.558 (days), and 1.300 (day-1), respectively, that was significantly different. It can be concluded that efficiency of T. embryophagum species compared with two other species, T. brassicae and T. pintoi on the carob moth eggs was higher. Therefore, it is recommended to use this species in integrated pest management program.