scholarly journals Sublethal effects of three insecticides on fitness parameters and population projection of Brevicoryne brassicae (Hemiptera: Aphididae)

2020 ◽  
Vol 113 (6) ◽  
pp. 2713-2722
Author(s):  
Leila Mahmoodi ◽  
Fariba Mehrkhou ◽  
Nurper Guz ◽  
Maryam Forouzan ◽  
Remzi Atlihan

Abstract The cabbage aphid, Brevicoryne brassicae (L.), is one of the major insect pests of cole crops in Iran. In most instances outbreaks are normally kept under control by application of insecticides. In this study, the sublethal effects (LC30) of three insecticides, acetamiprid, buprofezin, and thiamethoxam-lambda cyhalothrin, (TLC) were evaluated on the population growth rate of the progeny of insecticide-treated cabbage aphid adults. The age-stage, two-sex life table method was used to analyze the collected data. The results indicated that the insecticide applications affected the duration of the preadult period, their survival, reproduction, life span/longevity, and consequently, the population growth rate of the F1 generation. The indicators of the greatest sublethal effects were noted in the progeny of the TLC-treated adults. These included the lowest net reproductive rate (R0), intrinsic rate of increase (r), finite rate of increase (λ), and the longest mean generation time (T). The highest values of r, λ, R, and the lowest value of T occurred in the control group followed by, in order, the acetamiprid and buprofezin groups. These research findings will be useful in the development and implementation of future aphid management programs.

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0250311
Author(s):  
Aonan Zhang ◽  
Lin Zhu ◽  
Zhenghao Shi ◽  
Tianying Liu ◽  
Lanlan Han ◽  
...  

The soybean aphid Aphis glycines Matsumura (Hemiptera: Aphididae) is a primary pest of soybeans and poses a serious threat to soybean production. Our studies were conducted to understand the effects of different concentrations of insecticides (imidacloprid and thiamethoxam) on A. glycines and provided critical information for its effective management. Here, we found that the mean generation time and adult and total pre-nymphiposition periods of the LC50 imidacloprid- and thiamethoxam-treatment groups were significantly longer than those of the control group, although the adult pre-nymphiposition period in LC30 imidacloprid and thiamethoxam treatment groups was significantly shorter than that of the control group. Additionally, the mean fecundity per female adult, net reproductive rate, intrinsic rate of increase, and finite rate of increase of the LC30 imidacloprid-treatment group were significantly lower than those of the control group and higher than those of the LC50 imidacloprid-treatment group (P < 0.05). Moreover, both insecticides exerted stress effects on A. glycines, and specimens treated with the two insecticides at the LC50 showed a significant decrease in their growth rates relative to those treated with the insecticides at LC30. These results provide a reference for exploring the effects of imidacloprid and thiamethoxam on A. glycines population dynamics in the field and offer insight to agricultural producers on the potential of low-lethal concentrations of insecticides to stimulate insect reproduction during insecticide application.


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. 


2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Fatemeh Jafarbeigi ◽  
Mohammad Amin Samih ◽  
Mehdi Zarabi ◽  
Saeideh Esmaeily

The sweetpotato whitefly,Bemisia tabaci(Genn.) (Hem.: Aleyrodidae), is an important pest of agriculture in subtropical and tropical areas. In this study, we used the age-stage two-sex life table to evaluate the sublethal effects of the herbal extracts taken fromFumaria parvifloraLam. (Fumariaceae),Teucrium poliumL. (Lamiaceae),Calotropis procera(Willd.) R. Br. (Asclepiadaceae), andThymus vulgarisL. (Lamiaceae) as well as the two commercial synthetic insecticides, pymetrozin and neemarin. The whiteflies were exposed to each insecticide using leaf-dip method. Analysis of life table parameters revealed significant differences (P≤0.05) in the net reproductive rate (R0,NRR), intrinsic rate of increase (rm), and finite rate of increase (λ) among different insecticides. The lowest values of the three population parameters,R0,r, andλ, were observed on whiteflies treated with pymetrozin (2.455, 0.036, and 1.036),T. polium(2.828, 0.044, and 1.045), and neemarin (2.998, 0.046, and 1.047), respectively. Results of this study highlights the satisfactory insecticidal effects of the extract taken fromT. poliumonB. tabaci, which is comparable to the two commonly used synthetic insecticides.


2020 ◽  
Vol 20 (5) ◽  
Author(s):  
Yuping Gou ◽  
Peter Quandahor ◽  
Kexin Zhang ◽  
Sufan Guo ◽  
Qiangyan Zhang ◽  
...  

Abstract In order to investigate the effects of artificial diets on the population growth of root maggot Bradysia impatiens, its population growth parameters were assayed on eight artificial diets (Diet 1, D2, D3, D4, D5, D6, D7, and D8). Results showed that developmental duration from egg to pupa was successfully completed on all eight artificial diets. However, the egg to pupal duration was shortest, while the survival rate of four insect stages was lowest when B. impatiens was reared on D1. When B. impatiens was reared on D7 and D8, the survival rate, female longevity, and female oviposition were higher than those reared on other diets. When B. impatiens was reared on D7, the intrinsic rate of increase (rm = 0.19/d), net reproductive rate (R0 = 39.88 offspring per individual), and finite rate of increase (λ = 1.21/d) were higher for its population growth with shorter generation time (T = 19.49 d) and doubling time (Dt = 3.67 d). The findings indicate that the D7 artificial diet is more appropriate for the biological parameters of B. impatiens and can be used an indoor breeding food for population expansion as well as further research. We propose that vitamin C supplement added to the D7 is critical for the improvement of the B. impatiens growth.


Author(s):  
Ismail Kasap ◽  
Remzi Atlihan

The European red mite, Panonychus ulmi (Acari: Tetranychidae) is an important pest species on deciduous plants in Turkey, especially on apple. In this study, development, survival, and reproduction of European red mite, P. ulmi were studied on different host plants under laboratory conditions (25±2 °C,% 60±10 RH and16:8 L:D photoperiod). Population performance of P. ulmi was obtained on its different host plants including apple (Malus communis L.), quince (Cydonia oblonga Mill.), cherry (Prunus avium L.), and sour cherry (Prunus cerasus L). The life history raw data of P. ulmi were analyzed by using the age-stage, two-sex life table. Results indicated that the highest net reproductive rate, intrinsic rate of increase, and finite rate of increase as well as the longest mean generation time, were obtained on apple cv. Starking delicious. The population projection simulated by using life tables based on the 0.025th and 0.975th bootstrap results of the finite rate of increase displayed the same trend with population growth parameters. Results suggested that apple cv. Starking Delicious was the favorable host for P. ulmi, however, there is potential for the pest to become a serious pest on other host plants tested under favorable conditions.


2019 ◽  
Vol 63 (1) ◽  
pp. 149-155 ◽  
Author(s):  
Rajmund Sokół ◽  
Remigiusz Gałęcki ◽  
Maria Michalczyk

AbstractThe development of female Varroa destructor mites in the bee colonies was examined in the apiculture season through a developed research system in which bee colonies were experimentally infested with fifty V. destructor females. Differences in infestation rates were observed between the control group (C) and the infested group (E). The average number of female mites per colony was determined at 513 in group E and 261.6 in group C. Natural daily mortality reached 0.16 mites in group E and 0.09 mites in group C. In group E, the number of V. destructors increased 7.96 to 13.32-fold, subject to colony. The size of V. destructor populations increased at a higher rate in group E than in group C (F= 12.39, P= 0.047). At the end of the experiment, the percentage of infested honey bee workers was determined at 0.97% in group E and 0.46% in group C. The results of this study confirmed that V. destructor mites continue to proliferate rapidly in honey bee colonies, and that the population growth rate in bee colonies and apiaries has to be closely monitored due to growing levels of resistance to acaricides.


2020 ◽  
pp. 201-208
Author(s):  
A. Brandão ◽  
D.S. Butterworth

The upper bound of 0.126 on the maximum demographically possible annual growth rate for humpback whales that has standardly been imposedon recent applications of age-aggregated assessment models for this species in the IWC Scientific Committee, is based on an analysis that assumessteady age structure. It is conceivable that transient age-structure effects could admit greater population growth rates for short periods than suggestedby such a bound. This possibility is addressed by developing an age-structured population model in which possible density dependent changes inpregnancy rate, age at first parturition and natural mortality are modelled explicitly, and allowance is made for the possibility of natural mortalityincreasing at older ages. The model is applied to the case of the west Australian humpback whale population (Breeding Stock D), for which breedingground surveys over the 1982–1994 period provide a point estimate of 0.10 for the annual population growth rate. Results based upon the breedingpopulation survey estimate of abundance of 10,032 in 1999 suggest that 0.12 is the maximum demographically feasible annual rate of increase forthis stock over 1982–1994 if it is a closed population. This result is based on essentially the same parameter choices as led to the earlier r = 0.126bound, i.e. that in the limit of low population size the age at first parturition approaches five years from above, the annual pregnancy rate 0.5 frombelow, and the annual natural mortality rate 0.01 from above. Transient effects do not appear able to reconcile the observed rate of increase withless extreme values of demographic parameters than led to the previously imposed upper bound of 0.126 on the maximum possible annual growthrate. Although use of extreme values reported for demographic parameters for Northern Hemisphere humpback whale populations, rather than thoseconsidered here, would reduce this suggested maximum rate of 0.12, the conclusion that transient effects have a very limited impact on observedpopulation growth rates would be unlikely to change.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hongyan Wang ◽  
Tianrong Xin ◽  
Jing Wang ◽  
Zhiwen Zou ◽  
Ling Zhong ◽  
...  

AbstractPanonychus citri, a major citrus pest. In pest management, bifenazate is a novel acaricide with high biological activity against red mites, such as Tetranychus urticae Koch. However, in the field, pests are frequently exposed to sublethal or lethal concentrations of pesticides. At present, its sublethal effects on P. citri have not been reported. Therefore, in order to investigate sublethal effect of bifenazate on biological traits and enzymatic properties of P. citri. The newly emerged females were treated with two concentrations of bifenazate: LC10 and LC30, the development and fecundity were observed. The results showed that female adult duration, fecundity, oviposition days, longevity were decrease compared with control, but pre-oviposition period was longer, net reproductive rate (R0), mean generation (T) were decreased, intrinsic rate of increase (rm), finite rate (λ) were decreased in LC30, however, doubling time was increased. Enzymatic tests showed that CAT, POD, CarE activities were higher in treatments than control. The SOD and GST activities were lower in LC30 than control and LC10, the CYP450 activity was decreased with the increasing concentrations. This study demonstrated that low lethal concentrations of bifenazate adversely affected life table parameters, enzymatic properties in P. citri. Therefore, bifenazate has the potential to control this pest.


2014 ◽  
Vol 54 (2) ◽  
pp. 171-178 ◽  
Author(s):  
Saeideh Esmaeily ◽  
Mohammad Amin Samih ◽  
Mehdi Zarabi ◽  
Fatemeh Jafarbeigi

Abstract In addition to direct mortality caused by insecticides, some biological traits of insects may also be affected by sublethal insecticide doses. In this study, we used the age-stage, two-sex life table method to evaluate the sublethal effects of the four synthetic insecticides: abamectin, imidacloprid, diazinon, and pymetrozin as well as the botanical insecticide taken from Calotropis procera (Asclepiadaceae) extract, on eggs of the cotton whitefly, Bemisia tabaci (Hem.: Aleyrodidae). The lowest and highest survival rates and oviposition periods were observed in whiteflies treated by diazinon and imidacloprid, respectively. We found significant differences in the net reproductive rate (R0), the intrinsic rate of increase (r), the finite rate of increase (?), and the gross reproductive rate (GRR) among different insecticides. Altogether, our results showed that pymetrozin and C. procera induced the most sublethal effects, thus they may be suitable candidates for use in integrated pest management programs of B. tabaci.


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