The effects of Spiromesifen on life history traits and demographic parameters of predatory mite Neoseiulus californicus (Acari: Phytoseiidae) and its prey Tetranychus urticae Koch (Acari: Tetranychidae)

2019 ◽  
Vol 24 (8) ◽  
pp. 1512-1525
Author(s):  
Niloufar Sangak Sani Bozhgani1 ◽  
Katayoon Kheradmand ◽  
Aliasghar Talebi

Estimating sublethal effects of acaricides on phytoseiid mites and their prey as a reliable approach in predicting the acaricides impacts is mandatory for IPM programs. The aim of this study was to evaluate the effects of spiromesifen on life history traits and demographic parameters of the offspring of Neoseiulus californicus and Tetranychus urticae under laboratory conditions [25 ± 2ºC, 70 ± 5% RH and 16:8 (L:D) h]. The experiments were conducted based on the leaf-dip technique. The crude data were analysed based on age-stage, two-sex life table analysis. The pre-adult and adult longevity of both sexes significantly reduced for N. califonicus and T. urticae with the concentration enhancing from LC20 to LC35. In addition, the oviposition period for both species significantly decreased as a consequence of treatment with LC25 and LC35 of spiromesifen. The minimal values of the total fecundity for N. califonicus and T. urticae were 16.58 and 19.35 (offspring/individual), respectively, which was related to LC35 concentration. Further, the lowest values of R0 and GRR of N. califonicus and its prey were 48.88 and 31.14 (offspring/individual) in LC35, respectively. However, the intrinsic rate of increase (r) and finite rate of increase (λ) were not significantly influenced by sublethal concentration in N. californicus while the r and λ were significantly reduced in T. urticae treated by LC20, LC25 and LC35. Therefore, spiromesifen could profoundly decrease the population growth rate of T. urticae but can not be considered as a compatible acaricide with N. califonicus because of its negative effect on the longevity, total lifespan, and reproductive periods and should not be used with this predatory mite in integrated pest management programs.

2014 ◽  
Vol 74 (3) ◽  
pp. 691-697 ◽  
Author(s):  
PP Marafeli ◽  
PR Reis ◽  
EC. da Silveira ◽  
GC Souza-Pimentel ◽  
MA. de Toledo

The predatory mite, Neoseiulus californicus(McGregor, 1954) (Acari: Phytoseiidae) is one of the principal natural enemies of tetranychid mites in several countries, promoting efficient control of those mites in several food and ornamental crops. Pest attacks such as that of the spider mite, Tetranychus urticaeKoch, 1836 (Acari: Tetranychidae), is one of the problems faced by farmers, especially in the greenhouse, due to the difficulty of its control with the use of chemicals because of the development of fast resistance making it hard to control it. The objective of this work was to study the life history of the predatory mite N. californicus as a contribution to its mass laboratory rearing, having castor bean plant [Ricinus communis L. (Euphorbiaceae)] pollen as food, for its subsequent use as a natural enemy of T. urticae on a cultivation of greenhouse rosebushes. The studies were carried out in the laboratory, at 25 ± 2°C of temperature, 70 ± 10% RH and a 14 hour photophase. The biological aspects and the fertility life table were appraised. Longevity of 32.9 days was verified for adult females and 40.4 days for males. The intrinsic rate of increase (rm) was 0.2 and the mean generation time (T) was 17.2 days. The population doubled every 4.1 days. The results obtained were similar to those in which the predatory mite N. californicus fed on T. urticae.


2017 ◽  
Vol 22 (1) ◽  
pp. 148 ◽  
Author(s):  
Ya Ying Li ◽  
Xiao Fan ◽  
Guo Hao Zhang ◽  
YI QING LIU ◽  
HAN QIU CHEN ◽  
...  

Traditional estimating only by measuring the lethal effect of acaricides may underestimate the total effects of acaricides on the pest mites. In order to investigate the sublethal effect of bifenazate on life history and population parameters of the two-spotted spider mite, Tetranychus urticae Koch, the newly emerged females were treated with two lethal concentrations of bifenazate: LC10 (4.92 μg/mL) and LC20 (8.77 μg/mL). Subsequently, the development and fecundity of the progeny generations were observed. Compared to the control, exposure to the 10% lethal concentrations (LC10) and LC20 of bifenazate severely affected the parental generation of T. urticae, including survival rate (reduced 9% and 13%), oviposition period (reduced 77.6% and 83.1%), fecundity per female (decreased 89.2% and 76.9%) and longevity (decreased 79.2% and 83.1%). Besides, the population parameters of the progeny generation from the treated females were also investigated. The results showed that the progeny generation had lower intrinsic rate of increase (rm) and finite rate of increase (λ), longer mean generation time (Tc) compared to the control. The results suggested that the sublethal effects of bifenazate on population growth of T. urticae were significant, and the results of this study could be used as a guide for the rational use of bifenazate in the field for better managing pest mites.


2018 ◽  
Author(s):  
Jingqi Ouyang ◽  
Yajing Tian ◽  
Chunxian Jiang ◽  
Qunfang Yang ◽  
Haijian Wang ◽  
...  

AbstractObjectiveExploring the effects of acaricides on predatory mites is crucial for the combination of biological and chemical control of pests. In this study, sublethal effects of the new acaricide SYP-9625 on Tetranychus cinnabarinus (Boisduval), effects of application concentration of SYP-9625 on the predatory mite Neoseiulus californicus (McGregor) and functional responses of N. californicus were assessed. The aim of the present study was to evaluate and explore the application of new acaricide SYP-9625 with natural enemy N. californicus.MethodAll the experiments were under laboratory conditions [25 ± 1 °C, 16:8 (L:D) h and 75 ± 5% RH] and based on an age-stage, two-sex life table. The sublethal concentrations against T. cinnabarinus, including LC10 (0.375 μg/mL) and LC30 (0.841 μg/mL) and the application concentration (100 μg/mL) of SYP-9625, were used to evaluate effects on population parameters of N. californicus.ResultT. cinnabarinus females treated with LC30 exhibited significantly reduced net reproductive rates (R0=11.02) of offspring compared to females treated with LC10 (R0=14.96) and untreated females (>R0=32.74). However, the intrinsic rate of increase (rm) and finite rate of increase (λ) of N. californicus indicated that the application concentration of SYP-9625 had no significant negative effect on treated N. californicus eggs (rm=0.277, λ=1.319) compared to the control (rm=0.292, λ=1.338). Additionally, the sublethal concentrations against T. cinnabarinus including LC10 and LC30 showed a dose-dependent mechanism on the predatory mite. SYP-9625 also stimulated the predatory capacity of N. californicus against immobile stages such as eggs and larvae.ConclusionIt is demonstrated that sublethal concentrations of SYP-9625 can inhibit population growth of T. cinnabarinus. And the sublethal concentrations and application concentration had little effect on the population growth of N. californicus. The two advantages showed great commercial potential of this new acaricide. Therefore, N. californicus can manage T. cinnabarinus populations effectively with appropriate SYP-9625 concentrations.


Author(s):  
Samira Khodayari ◽  
Maryam Hashemian Shalilvand

The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) is an important pest of pepper (Capsicum annuum L.). Control of this pest is usually dependent on chemical pesticides. The use of resistant plant cultivars in conjugation with other control tactics generates more effective and long lasting results in management of many pests. In this study we used two-sex life table to evaluate the performance of T. urticae on five pepper cultivars (11983, ES4, Hashemi, Mahali and USL) before and after blooming of host plants. The results showed that the immature time, adult longevity and fecundity differed significantly among cultivars. Before blooming on 11983, the values for the intrinsic rate of increase (r) and the finite rate of increase (λ) were 0.0645 and 1.066 day-1 respectively, which were significantly the lowest; the highest r and λ values was recorded on ES4 which were 0.1347 and 1.144 day-1 respectively. After blooming there was no significant difference in these values among cultivars except for Mahali in which these values were significantly the highest (0.0751 and 1.078 day-1 respectively). Comparing between the phenological stages of host plants (before and after blooming) indicated that after blooming all of the tested pepper cultivars were more resistant to T. urticae. In summary, among the different cultivars tested, the most suitable was ES4 and the least suitable was 11983 before blooming of host plants. After blooming the suitability of host plants changed and decreased significantly.


2017 ◽  
Vol 22 (10) ◽  
pp. 1748 ◽  
Author(s):  
Irena Međo ◽  
Bojan Stojnić ◽  
Dejan Marčić

Laboratory bioassays were conducted to evaluate the toxicity of the microbial pesticide spinosad to different life stages of the two-spotted spider mite, Tetranychus urticae Koch, as well as its sublethal effects on reproduction and population growth of this important mite pest. The biopesticide was applied to bean primary leaves or leaf discs carrying spider mites using a Potter spray tower (2.7 mg/cm2 aqueous deposit). The following LC50 and LC90 (mg/L) estimates for motile stages were obtained in acute toxicity bioassays: 27.52 and 116.72 (larvae), 36.55 and 136.20 (protonymphs), 82.76 and 721.28 (female deutonymphs), and 61.47 and 457.21 (adult females). Spinosad showed no significant ovicidal action: toxic effect observed after spraying eggs (LC50 = 105.78 mg/L, LC90 = 596.95 mg/L) was the result of its residual action on larvae that hatched from the treated eggs. The effects of spinosad on life history traits and population growth of adult female survivors from treatments with 240, 120 and 60 mg/L were evaluated in two successive 7-day bioassays on untreated leaf discs. In the first bioassay, females that survived treatments as 24 h old eggs and completed their juvenile development on treated leaves had significantly lower gross fecundity, net fecundity and instantaneous rate of increase (ri) but the reduction was merely 4–6%, 9–11%, and 2–3%, respectively. Female longevity was significantly reduced (approximately by half a day) only after treatment with 240 mg/L. In the second bioassay, in which females were treated during their pre-ovipositional period, the treatments with 240 and 120 mg/L significantly reduced their gross fecundity (16–17%), net fecundity (28–31%), ri values (8–9%) and female longevity (approximately by one day). Spinosad effects on the intrinsic rate of increase (rm) and other demographic parameters were evaluated in two successive bioassays in which life tables were constructed for females that survived treatment with 120 mg/L at the egg stage (first demographic bioassay) or pre-ovipositional period (second demographic bioassay). In the first bioassay, the intrinsic rate of increase was significantly higher in treated (rm = 0.278) than control mites (rm = 0.267) as a result of higher net fertility at the beginning of reproduction of treated females. In the second bioassay, treated females had significantly lower rm than control females (0.254 and 0.283, respectively). The results obtained in this study indicate that spinosad, applied against insect pests (at field relevant rates of 60–240 mg/L), could eliminate a part of T. urticae population as well, but survivors would retain a significant potential for population recovery. 


Author(s):  
Suqin Shang ◽  
Yun Chang ◽  
Wei-Zhen Li ◽  
Wang Chang-Qing ◽  
Nie Peng-Cheng

AbstractThe present study was conducted to evaluate sublethal effects of B-azolemiteacrylic on the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae). Female adults of T. urticae were exposed to LC10 and LC30 of the acaricide, and the effects on treated females and their offspring were evaluated. The results showed that the fecundity of F0 female adults treated with LC10 and LC30 of B-azolemiteacrylic was reduced by 30.9 and 39.2%, respectively. Longevity and oviposition period of the females were significantly reduced as well. The developmental duration of egg and deutonymph stage of the F1 generation were not significantly different from that of the control. The protonymph stage after LC30 treatment lasted significantly longer, whereas the larva, deutonymph and female stage were significantly shorter than the control. The oviposition period of the F1 generation was significantly shortened, the fecundity of each female decreased significantly, and the ratio of female-to-male was reduced too. Moreover, the average generation period of T. urticae after LC10 and LC30 treatments was shorter than that of the control, and the net production rate (R0), intrinsic rate of increase (rm) and finite rate of increase (λ) were all reduced by 33.3, 7.5 and 1.9% (LC10 treatment) and by 51.3, 14.8 and 3.6% (LC30 treatment), respectively. The population doubling time was prolonged by 7.5 and 14.8% after LC10 and LC30 treatments, respectively, compared with the control. These results indicate that B-azolemiteacrylic may effectively inhibit the development rate of the F0 and F1 populations of T. urticae, which will help design integrated strategies for the comprehensive control of T. urticae and rational use of pesticides in the field.


2020 ◽  
Vol 25 (3) ◽  
pp. 411
Author(s):  
Mohammadreza Havasi ◽  
Katayoon Kheradmand ◽  
Hadi Mosallanejad ◽  
Yaghoub Fathipour

Knowledge of the effects of pesticides on biological control agents is necessary for the successful implementation of integrated pest management programs. Laboratory bioassays were conducted to evaluate the effects of Biomite®, a natural acaricide, on the life table parameters of Neoseiulus californicus McGregor (Acari: Phytoseiidae), as one of the most important natural enemies of Tetranychus urticae Koch (Acari: Tetranychidae) under laboratory conditions at 25 ± 2°C, 65 ± 5% RH and a photoperiod of 16:8 (L:D) h. The raw data were analyzed based on the two-sex life table theory. Biomite® concentrations LC10 and LC20 gradually and significantly reduced the longevity and total life span of both sexes, as well as total fecundity. Besides, concentration LC20 significantly reduced the gross reproductive rate (GRR) and the net reproductive rate (R0). However, the intrinsic rate of increase (r) and the finite rate of increase (λ) were not significantly affected. Thereby, due to an unfavorable shortened in life history characters of N. californicus such as total life span, reproductive periods and biological parameters (such as R0 and GRR), as a consequence of Biomite® treatment, it can be concluded that this acaricide should not be used with N. californicus in integrated pest management programs.


Author(s):  
Fatemeh Pirayeshfar ◽  
Seyed Ali Safavi ◽  
Hamid Reza Sarraf-moayeri ◽  
Gerben J Messelink

Blattisocius mali (Oudemans) is a candidate predatory mite on some astigmatid mite pests like Tyrophagus putrescentiae (Schrank). In current study, life table parameters of B. mali were comparatively evaluated when fed on mixed life stages, frozen (one day at -20°C) and cold stored (90 days at -20°C and 4°C) eggs of T. putrescentiae. The highest and lowest values of fecundity, total longevity, oviposition period, life span and adult longevity of B. mali were observed when the predator provided with one-day and 90-days frozen eggs (stored at 4°C) of T. putrescentiae, respectively. Moreover, the highest values of net reproductive rate (R0), intrinsic rate of increase (r) and finite rate of increase (λ) of B. mali were obtained by feeding on one-day frozen eggs (23.94 offspring/individual, 0.332 day-1, 1.39 day-1, respectively), without significant differences from the predators reared on alive mixed stages of T. putrescentiae. However, the lowest values of R0 (1.54 offspring/individual), r (0.058 day-1) and λ (1.06 day-1) were recorded when B. mali was reared on 90-days frozen eggs (stored at 4°C). The results, as first evidence of life-history of B. mali, represent not only the potential of the predator as suitable biological control agent against T. putrescentiae, but also the possibility of its mass production by frozen host stages. Provision of one-day frozen eggs of T. putrescentiae were the best choice for B. mali survival and reproduction with no harmful effects of living stages (direct damage, frass and exuviae) on crop.


2020 ◽  
Vol 25 (1) ◽  
pp. 125-138
Author(s):  
Mohammadreza Havasi ◽  
Katayoon Kheradmand ◽  
Hadi Mosallanejad ◽  
Yaghoub Fathipour

Knowledge of the effects of pesticides on biological control agents is necessary for the successful implementation of integrated pest management programs. Laboratory bioassays were conducted to evaluate the effects of Biomite®, a natural acaricide, on the life table parameters of Neoseiulus californicus McGregor (Acari: Phytoseiidae), as one of the most important natural enemies of Tetranychus urticae Koch (Acari: Tetranychidae) under laboratory conditions at 25 ± 2°C, 65 ± 5% RH and a photoperiod of 16:8 (L:D) h. The raw data were analyzed based on the two-sex life table theory. Biomite® concentrations LC10 and LC20 gradually and significantly reduced the longevity and total life span of both sexes, as well as total fecundity. Besides, concentration LC20 significantly reduced the gross reproductive rate (GRR) and the net reproductive rate (R0). However, the intrinsic rate of increase (r) and the finite rate of increase (λ) were not significantly affected. Thereby, due to an unfavorable shortened in life history characters of N. californicus such as total life span, reproductive periods and biological parameters (such as R0 and GRR), as a consequence of Biomite® treatment, it can be concluded that this acaricide should not be used with N. californicus in integrated pest management programs.


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