جستجوی مقالات مرتبط با کلیدواژه « spotted spider mite » در نشریات گروه « گیاهپزشکی »

The two-spotted spider mite is a cosmopolitan species that exist in wide areas of the world and fed from different varieties of plants. The control of this pest was done by chemical pesticides and acaricides. Due to the high cost of chemical compound and problems such as durability and environmental pollution, alternative control means are necessary. Plants may provide potential alternatives to currently used insect control agents. Plant materials have several advantages over traditional pest control agents; such as specificity, biodegradability and low mammalian toxicity. Sirinol is a natural compound based on garlic extract. Spirodiclofen with a trade name of Envidor® is a broad spectrum acaricide acting via lipid biosynthesis inhibition (LBI) with no cross-resistance to currently available acaricides and with additional insecticidal properties. Envidor is positive IPM listed but in the frame of resistance, management limited to one application per season. In pear growing Envidor constitutes an important tool in pear sucker control in a tandem strategy with abamectin. In this research, the effect of this compound was investigated on the egg and adult of T. uricae under laboratory and field condition.
Materials and Methods Rearing of T. urticae: An initial mite colony was collected from infected fields in Sari and was transferred to the laboratory in Sari Agricultural Science and Natural Resource University, plant protection department. The adult mites were released on the bean leaves (3 weeks after leaves germination) and removed 24 h after treatment. Infected plants to mite eggs were placed in a growth incubator at 25±2˚C, 65±5% RH and 16:8 photoperiods. 12 days after treatment and emerging of adults, they were used for the bioassay.
Bioassay: First of all, primary experiments were performed to determine the minimum and maximum concentrations. Then, seven concentrations and also control were considered. The concentrations used for sirinol were 250, 381, 593, 922, 1434, 2230 and 3500 ppm and for spirodiclofen were100, 134, 180, 242, 326, 438 and 600 ppm. The original bean leaf discs (30 mm diameter) were cut and 15 adults of T. urticae were released on each leaf. Then, 500 microliters of each concentration was sprayed on the leaves using spray potter tower and the leaves were put on the petri plates containing moist cotton. The treatments were placed in a growth incubator at 25±2˚C, 65±5% RH and 16:8 photoperiods. The number of dead mites was counted at 24, 48 and 72 hours post-treatment. To evaluate the effect of three concentrations 1000, 2000 and 4000 ppm of sirinol and 300, 600 and 1200 ppm of spirodiclofen an experiment with seven treatment and four replications was conducted in a randomized complete design under field condition. The numbers of T. urticae and P. persimilis (egg and adult) on leaf samples were counted one day before treatment and 3, 7, 14 and 21 days after treatment.
Statistical analyses: The mortality results were analyzed statistically using SPSS data processing software. Significant differences among the groups were determined using the unpaired Duncan-test. A value of P

Temperature is one of the important factors that can influence the predator- prey dynamics. In this research, functional responses of males and females of Orius laevigatus towards Tetranychus urticae nymphs were investigated in laboratory condition at three constant temperatures, 20, 25 and 30°C. Different densities of mixture of protonymph and deutonymph of mite (2, 4, 8, 16, 32 and 64), on cucumber leaf discs (6 cm in diameter), were separately offered to male and female predators. After 24 h, the number of consumed preys was recorded. Ten replicates of the experiment were performed. Logistic regression and nonlinear regression of SAS software were used to determine the type of functional response and estimate the parameters, respectively. Consumption rate of both male and female predators increased with increasing temperature and prey density. Functional responses of both male and female predators to the mite were Type II at 20 and 25°C and Type III at 30°C. At 20 and 25°C, attack rates were estimated to be 0.0452 and 0.0498 h-1for females; and 0.0457 and 0.0460 h-1 for males, respectively. The lowest handling time for both male and female predators was estimated at 25°C. The results revealed that the predatory bug O. laevigatus may be more effective for biological control of T. urticae at higher temperature.

Two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), is one of the most important pests of tomato crops. Using resistant cultivars is a useful control method against the pest in integrated pest management programs. In this study, resistance of the tomato cultivars Super Chief, Super Strain B, Korral, Khorram, HAS 2274, Super H, Calji, Early Urbana Y and Mobil to two-spotted spider mite were evaluated under laboratory conditions at 25 ± 2 °C, 60 ± 10% R.H. and a photoperiod of 16: 8 (L: D).The shortest pre-adult stage was recorded on Super Strain B. Female life span ranged from 26.47 to 30.40 days, on Super Chief and Early Urbana Y, respectively. The intrinsic rate of increase (rm) was from 0.091 to 0.163 day-1 which the lowest rm was observed on Super Chief and the highest rm was on Super Strain B. The lowest net reproductive rate (R0) and finite rate of increase (λ) belonged to Super Chief cultivar. Super Chief cultivar showed the highest antibiosis resistance against the two-spotted spider mite.

Recently, the use of plant essential oil as natural compound for protecting crops and decreasing environmental pollutions has been considered. In this study, contact and fumigant toxicity of peel essential oil of Citrus sinensis singly and in combination with spirodiclofen and propergite were evaluated against adult females of two-spotted spider mite, Tetranychus urticae. Median lethal concentration (LC50) values of essential oil of orange peel in the contact and fumigant toxicity assay, were 11.48 μg/cm2 and 48/75 μl/l air, respectively. Contact toxicity of C. sinensis essential oil in comparison with the two chemical compounds showed that T. urticae was more sensitive to spirodiclofen (LC50= 2.76 μg/cm2) than the essential oil, while propargite was less efficient (LC50= 28.51 μg/cm2). Furthermore, mixture of propargite and essential oil of orange peel (both at LC25) showed a mortality less than the total expected mortality (50 %). In contrast, mortality of LC25 of spirodiclofen mixed with C. sinensis essential oil was much higher than that of the total expected mortality (96.66 %). According to co-toxicity coefficient (CTC) factor, mixtures of C. sinensis essential oil with propargite and spirodiclofen, exhibited antagonistic and synergistic effects, respectively.

The goal of this investigation was to study the effectivenessy of different acaricides on the control of twospotted spider mite (TSSM) at different mite population densities. Study was conducted based on the randomized complete block design (RCBD) using split plot experiment. When the pest population exceeded 3, 5 and 7 mites on the abaxial surface of each leaf in the main plot, spraying was done by sub plot treatments including: fenazaquin (Pride® SC 20%) at the rate of 0.5 lit/ha, fenpyroximate (Ortus® SC 5%) at the rate of 0.5 lit/ha, bromopropylate (Neoron® EC 25%) at the rate of 2 lit/ha and only water as control. Sampling was done 1 day before, 3, 7 and 14 days after each spraying. For sampling, 30 leaves were selected randomly from each treatment and the number of mites (adults & nymphs) was counted at 2 cm² area of under surfaces of the leaves. Mortality percentage of mites was calculated using Abbot and Henderson Tillton formulas. After normalizing the data, mean comparison was carried out using Duncan Multiple Range Test. Results indicate significant differences among the main plot factors, and treatment in the 1st and 2nd levels (3 and 5 mites on abaxial surface of each leaf, respectively) was more effective than the 3rd level 7 mites on abaxial surface of each leaf). Mean comparison of the mite mortality among different acaricides showed that bromopropylate with 97.8 and 95.8% mortality at day 14 (in the 1st and 2nd sampling time, respectively) was more effective than fenazaquin and fenpyroximate. It could be concluded that taking population density of the pest into consideration for choosing the right spraying time can increase the effectiveness of the acaricides.

Two-spotted spider mite, Tetranychus urticae Koch, is one of the important pests of cucumber, which can cause severe damage on it. Vermicompost is one of the organic fertilizers, as its addition to the soil can decrease the population of the pest. In this research, effect of four different vermicompost: soil ratios including 0:100 (control), 10:90, 20:80 and 30:70 % was investigated on biological and population growth parameters of T. urticae. The experiments were carried out in Petri dishes in a growth chamber at 25 ± 2 °C, 65 ± 5 % RH and 16 L: 8 D. The duration of developmental stage, was significantly affected by vermicompost ratios. The longest immature period, shortest longevity of females and shortest oviposition period were obtained at 30:70 % ratio. Furthermore, vermicompost ratios significantly affected population growth parameters of the mite. The intrinsic rate of natural increase (rm) of the mite ranged from 0.216 to 0.247 day-1, which its lowest and highest values were at 30:70 % ratio and control plants, respectively. The lowest net reproductive rate (R0) and finite rate of increase (λ) of the mite and the highest value of mean generation time (T) and doubling time (DT) were estimated at 30:70 % ratio. The results of this study showed that 30:70 % ratio had better potential for decreasing the population of the two-spotted spider mite and it can be used in the mite IPM programs.

Two-spotted spider mite (Tetranychus urticae Koch.) is an important pest on common bean in Iran which causes quantitative and qualitative damages to legumes. Its activity on the backside of host leaves reduces the efficiency of sprayer machines. In this research, efficiency of six sprayer machines using two concentrations of hexythiazox (Nissorun®, 0.5 and 0.3 L/ha) were studied. The experimental design was a factorial test conducted based on the completely randomized block design with 14 treatments in 3 replications. The sprayers included wheelbarrow sprayer 100 liters), atomizer sprayer with simple head, atomizer sprayer with electrostatic head, atomizer sprayer with micronair head, micronair sprayer with tail boom and knapsack sprayer. Sampling of T. urticae population was performed one day before and 1, 3, 5, 7, 14, 21 and 28 days after spraying. The results show that the highest and the lowest efficiency percentages are 83.74 and 23.46% for electrostatic sprayer and micronair sprayer with tail boom, respectively. Also, the efficiency percentages for other sprayers measured are 76.50%, 57.41%, 43.22%, and 36.81 for wheelbarrow sprayer, atomizer sprayer with micronair head, atomizer sprayer with simple head and knapsack sprayer, respectively. The amount of solution used in the electrostatic sprayer, atomizer sprayer with micronair head and micronair sprayer with tail boom were 42.69, 134.4 and 56.25 l/ha, respectively, which indicates decrease in the consumption as compared with the others. Hence, the electrostatic sprayer is recommended as the most effective sprayer for the control of Two-spotted spider mite in the bean fields.

Arthropod development is affected by temperature. Knowledge of relationship between temperature and mite developmental rates is useful in biological and ecological studies. Effect of six constant temperatures (15، 20، 25، 30، 35، 40) on developmental rate of all stages of two-spotted spider mite، Tetranychus turkestani Ugarov & Nicolski، were investigated under laboratory conditions at 55 10% R. H and a photoperiod of 16:8 L: D and developmental rate of the mite modeled as a function of temperature. The performance of one linear and 11 nonlinear developmental rate models (Logan–6، Logan–10، Sharp and DeMichele، Taylor، Lamb-1، Lamb-2، Hilbert and Logan، Briere–1، Briere–2، Lactine–1 and Lactine–2) were compared and based on the criteria such as adjusted coefficient of determination (R2)، the residual sum of squares (SSR) and estimation of biological parameters the best model was selected. The results indicated that the Briere–2 model (R2= 0. 996، SSR = 0. 00022) was the best model for description of the mite biological parameters.

Two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae) is one of the most important pests of cucumber. In order to investigate the effect of different concentrations of potassium on biology and life table of this mite, cucumber plant was nourished by three levels of potassium including deficiency level of potassium K1 (5 meq/l K+), standard level of potassium K2 (7 meq/l K+) and excess level of potassium K3 (9 meq/l K+). The experiments were performed under laboratory conditions at 25±1 C°, 60±5% relative humidity and a photoperiod of 16:8 (L:D) hours. Based on the obtained results, the mean of pre-imaginal developmental time in deficiency, standard and excess levels of potassium was 11.66, 12.15 and 11.35 days for males and 12.2, 11.78 and 10.73 days for females, respectively. The highest mean of females life span was observed in plants which nourished by the lowest concentration of potassium and showed significant different with two other levels of potassium. The maen of oviposition period in mentioned levels was 13.71, 8.18 and 11.72 days, respectively. Also the maximum value of total fecundity was recorded in deficiency level of potassium. Mortality percentage of pre-imaginal stages was estimated 30.74, 23.65 and 20.34% in mentioned levels, respectively. Age specific survival rate (lx) at adult emergence in deficiency, standard and excess levels of potassium was estimated 0.55, 0.66 and 0.73, respectively. The highest value of life expectancy (ex) in the start of the experiments was recorded as 35.31 days in 9 meq/l K+ concentration. The results showed that deficiency of potassium in cucumber plants is caused more reproduction in two- spotted spider mite. So proper management of plant nutrition can be one of the most effective strategies to control this pest in integrated pest management programs.

The effect of fenpyroximate on life table parameters of two-spotted spider mite Tetranychus urticae Koch was evaluated under laboratory conditions (25±20C, 60±5% RH and 16:8 L:D). Data were analyzed on the basis of age-stage, two-sex life table theory. The estimated value of LC50 for T. urticae was found to be 380 Ml/l. Durations of total preadult stage and preoviposition period in T. urticae treated with fenpyroximate (12.64 and 2.36 d, respectively) were significantly longer than those in control (11.56 and 1d, respectively). The lifetime fecundity of T. urticae treated with fenpyroximate was 1.35 (eggs/female) compared with control (52.27 eggs/female).The instric rate of increase (r), finite rate of increase (λ), net reproductive rate (R0), the mean generation time (T) and Gross Reproduction Rate (GRR) in T. urticae treated with fenpyroximate were -0.001 d-1, 0.998 d, 0.96 offspring, 14.25 d, 2.94 offspring, respectively. The study shows that the LC50 of fenpyroximate decreases the fecundity of two-spotted spider mite under laboratory conditions and makes the pest population growth almost face extinction. So the acaricide can be effectively used in two-spotted spider mite control.

Two-spotted spider mite, Tetranychus urticae Koch, is one of the important pests of common bean that causes serious damage to agricultural crops. In this study, nineteen common bean genotypes were evaluated for resistance to the two-spotted spider mite. The trial was carried out at field conditions of Karaj, Brojerd and Khomein. One week after mite infestation, the total number of female and eggs were counted for two times. Also, mite damage feeding was evaluated with a 1-6 scale. Khomein had the fewest infested mean and relative resistance of many genotypes was failed in comparison to susceptible standard genotype (Akhtar) at Khomein. So they should be eliminated in alternative breeding programs. Nevertheless, only Ks41128 that had good relative resistance at other regions had the most relative resistance at Khomein. Subsequently, we propose Ks41128 as the most resistance and also the most stable genotypes.

Herbivore induced plant volatiles (HIPVs) can be produced by herbivores attack that affects on ecology and behavioural responses of natural enemies. Damaged plant attracts natural enemies due to change the volatile compounds constitute by an active biochemical processes. This study was conducted to test whether green bean HIPVs, as well as odours emitted directly from spider mites influenced the orientation behaviour of the predatory mirid bug, Macrolophus caliginosus Wagner. A Y-tube olfactometer was used to determine the attraction of the predator to herbivore induced volatiles from Tetranychus urticae Koch infested green bean plants over clean plants and to direct prey odours over clean air. The mirid bugs showed a stronger response to odours from infested plants than to those from clean plants. The mirids, however, did not seem to exploit odours emitted directly from the preys themselves. Compounds of infested and uninfested plant volatile blends were also determined by gas chromatography-mass spectrometry (GC-MS). Of a total of 36 infested green bean compounds, 29 compounds are emitted either by uninfested green bean. The results from GC-MS analysis confirm that volatile blends emanate from bean infested by spider mites is different to clean bean and the attractiveness of predatory mirid bugs to infested plant over clean bean is probably resulting in these differences.