scholarly journals Fertility Lifetables of Glasshouse Whitefly Trialeurodes vaporariorum (Westwood) on French Bean cv. Contender at Different Temperatures

2020 ◽  
Vol 7 (1) ◽  
pp. 001-005
Author(s):  
Jyoti Kapil ◽  
◽  
Manica Tomar ◽  

Fertility Life tables and characteristics of the Trialeurodes vaporariorum (Westwood) were assessed on French bean cv. Contender at different temperatures 15, 20, 25 and 30 °C. The life table analysis showed that the females lived for a maximum of 58 days at 15 °C. The trend of oviposition showed a peak on 32nd day at 25 °C as the highest number of eggs produced per female per day was 9.98. The true Intrinsic rate of increase (rm) values were 0.123 and 0.121 at 20 °C and 25 °C, respectively. The rate of natural increase (rc) was 0.120 at 20 °C and 25 °C. The highest net reproductive rate (45.86) was obtained at 20 °C. The population doubling time (DT) was maximum (10.42 days) at 15 °C and minimum (5.64 days) at 20 °C. Generation time was 47.17 days at 15 °C which decreased to 24.82 days at 30 °C.

Insects ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 181
Author(s):  
Weiwei Sun ◽  
Miao Cui ◽  
Liyuan Xia ◽  
Qing Yu ◽  
Yang Cao ◽  
...  

Cheyletus malaccensis Oudemans is a predatory mite inhabiting grain depots in China. The relationship between temperature and the population growth rate of C. malaccensis is useful for predicting its population dynamics. Age-stage, two-sex life tables of the predator, C. malaccensis, reared on Acarus siro were constructed under laboratory conditions at 22, 24, 28, 30, and 32 °C, 75% relative humidity, and a 0:24 h (L:D) photoperiod. Increasing temperature shortened the development time of the immature stages. The complete generation time of C. malaccensis ranged from 11.10 d to 27.50 d. Life table parameters showed that 28 °C was the optimum temperature for the growth and development of C. malaccensis; populations could increase rapidly at this temperature. The highest net reproductive rate (R0 = 290.25) and highest fecundity (544.52) occurred at 28 °C. Temperature significantly affected the intrinsic rate of increase (r), fecundity, and finite rate of increase (λ). The values of age-specific fecundity (high to low) were 28 °C > 24 °C > 30 °C > 32 °C > 22 °C, while the values of age-stage-specific fecundity had the same trend.


PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0247978
Author(s):  
Maria Pobożniak ◽  
Małgorzata Gaborska ◽  
Tomasz Wójtowicz

Damage caused to cultivated carrots by the hawthorn-carrot aphid, Dysaphis crataegi Kalt. (Hemiptera: Aphididae) is one of the factors limiting carrot production in Poland. Planting resistant and tolerant cultivars could reduce yield losses due to the damage caused by this pest. This study was conducted to evaluate the resistance and/or tolerance of 10 carrot genotypes to hawthorn-carrot aphid. Their field resistance was determined under field conditions based on five indicators, namely, mean number of alates (migrants) per plant and mean percentage of plants colonized by them, mean seasonal number of aphids per plant, mean number of aphids per plant and mean percentage of infested plants at peak abundance. Antibiosis experiments were conducted under laboratory conditions and pre-reproductive, reproductive time, fertility, and demographic parameters, represented by the net reproduction rate (Ro), intrinsic rate of increase (rm) and mean generation time (T), were calculated. Five cultivars, Afro F1, Nipomo F1, Samba F1, White Satin F1, and Yellowstone showed field resistance. Antibiosis experiments revealed significant differences among the carrot cultivars in the length of the reproductive period, female fecundity in the time equal to the pre-reproduction time, and total progeny of hawthorn-carrot aphid. The intrinsic rate of natural increase (rm) for apterous aphids varied significantly, ranging between 0.181 (Nipomo F1) and 0.343 females/female/day (White Satin F1). Additionally, the estimated net reproductive rate (R0) was the lowest on Nipomo F1, and this genotype was determined to be resistant. Our results suggest that a very high density of trichomes on the leaf petioles (71.94 trichomes/cm2) could adversely affect the feeding, bionomy, and demographic parameters of hawthorn-carrot aphid on the cultivar Nipomo F1. In addition, Napa F1 and Kongo F1 demonstrated high tolerance. Considering all the results collectively, four genotypes, Afro F1, Kongo F1, Napa F1 and Nipomo F1, were relatively resistant/tolerant to the hawthorn-carrot aphid.


ENTOMON ◽  
2021 ◽  
Vol 46 (1) ◽  
pp. 11-24
Author(s):  
Nayan Roy

Oriental fruit fly, Bactrocera dorsalis, is a serious invasive pest in tropical and subtropical countries. The stage-specific two-sex pooled life table of B. dorsalis on four different fruits (guava, water apple, rose apple and mango) were studied during 2018-2020. The life table showed that the survivorship of B. dorsalis falls in Type III with about 41.394-33.827per cent of the eggs successfully reached adult stage. The highest mortality recorded was in the egg and adult emergence stages with kx of 0.045-0.113 and 0.032-0.192, respectively. The average potential fecundity (Pf) was 223-362 eggs female-1. The intrinsic rate of natural increase (rm) was 0.021-0.035 female-1 day-1 with mean generation time (Tc) of 194.058-148.710 days. The net reproductive rate (Ro) was 61.504-176.006 female offspring per female and the population doubling time (DT) was within 32.719-19.946 days. The population dynamics of B. dorsalis were significantly influenced by the host fruits due to their respective phytoconstituents in terms of host suitability or susceptibility (guava> water apple> rose apple> mango). Host preference of B. dorsalis was in the order of guava> water apple>rose apple.


2015 ◽  
Vol 20 (3) ◽  
pp. 93-97 ◽  
Author(s):  
Nataly DE LA PAVA S ◽  
Paula Andrea SEPÚLVEDA-CANO

<p>Este trabajo describe los parámetros biológicos y poblacionales del pulgón negro, <em>Aphis craccivora</em> Koch,<strong> </strong>sobre fríjol caupí (<em>Vigna unguiculata</em> (L. Walp.)), bajo condiciones de laboratorio. Los insectos se criaron sobre plántulas individualizadas a una temperatura promedio de 28 °C, humedad relativa de 70 % y fotoperiodo de 12 horas. Los parámetros medidos fueron periodo ninfal, fecundidad, supervivencia, periodo pre-reproductivo y aspectos relativos a la tasa de crecimiento del áfido. La tasa reproductiva neta R (<sub>0</sub>) fue 66,00, la tasa intrínseca de crecimiento del áfido (r<sub>m</sub>) fue 0,51, el tiempo de duplicación de la población (TD) fue 2,3. Se analizaron las curvas de supervivencia (lx), fecundidad (mx), la duración del período ninfal y reproductivo del áfido. Los resultados difieren de los realizados en otras variedades de fríjol caupí, evidenciándose la susceptibilidad de la variedad criolla usada por los agricultores en la costa Caribe colombiana.</p><p><strong>Biology of Black Aphid (<em>Aphis Craccivora</em>: Aphididae) on Cowpea (<em>Vigna Unguiculata</em>, Fabaceae)</strong> </p><p>This research describes the population and biological parameters of the black aphid (<em>Aphis craccivora</em> Koch) on cowpea bean (<em>Vigna unguiculata</em> (L. Walp.)), under laboratory conditions. The insects were raised on individualized seedlings in an average temperature of 28 °C, at 70 % relative humidity during a photoperiod of 12 hours. The parameters measured were the nymphal period, fecundity, longevity, pre-reproductive period and aspects of aphid growth rate. The net reproductive rate R (0) was 66.00, the intrinsic g rate of increase of the aphid (rm) was 0.51, and the population doubling time (TD) was 2.3. Survival curves (lx), fecundity (mx), the duration of nymphal and the reproductive period of the aphid were analyzed. The results differ from those found in other varieties of cowpea beans, demonstrating the susceptibility of the native variety used by farmers in the Colombian Caribbean coast.<strong></strong></p>


2020 ◽  
Vol 110 (6) ◽  
pp. 756-766 ◽  
Author(s):  
Rahul Debnath ◽  
Syed Husne Mobarak ◽  
Paroma Mitra ◽  
Anandamay Barik

AbstractDiaphania indica (Saunders) (Lepidoptera: Crambidae) is an important phytophagous pest of Trichosanthes anguina L. in India. We studied life table parameters by age-stage, two-sex, amylolytic and proteolytic activities, and food utilization parameters of D. indica on the leaves of three T. anguina cultivars (Baruipur Long, Polo No. 1 and MNSR-1). Further, nutrients (total carbohydrates, proteins, lipids, amino acids and nitrogen) and antinutrients (total phenols, flavonols and tannins) in leaves were determined. The development time (egg to adult emergence) was the shortest on MNSR-1 (19.79 d) and the longest on Polo No. 1 (25.72 d). Fecundity was the highest and lowest on MNSR-1 (259 eggs) and Polo No. 1 (151.22 eggs), respectively. The lowest intrinsic rate of increase (rm) and net reproductive rate (R0) of D. indica on Polo No. 1 were 0.1112 d−1 and 27.22 offspring individual−1, respectively. The mean generation time (T) was the shortest on MNSR-1 (23.99 days) and the longest on Polo No. 1 (29.70 d). The larvae of D. indica fed with MNSR-1 had the highest level of amylolytic and proteolytic activities, and the lowest activities were in the larvae fed with Polo No. 1. The fifth-instar larvae fed with Polo No. 1 had the lowest consumption index and growth rate. The higher larval development time and lower fecundity of D. indica on Polo No. 1 were due to the lower level of nutrients and a higher level of antinutrients than other cultivars. Our results concluded that Polo No. 1 cultivar could be suggested for cultivation.


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.


Acarologia ◽  
2018 ◽  
Vol 58 (1) ◽  
pp. 52-61
Author(s):  
Samah Ben Chaaban ◽  
Brahim Chermiti ◽  
Serge Kreiter

The old world date mite Oligonychus afrasiaticus is an important spider mite pest of the date palms Phoenix dactylifera L. mostly in North Africa and the Middle East. A population of the predaceous mite Typhlodromus (Anthoseius) athenas has been recently found in Tunisia in association with a decrease of O. afrasiaticus densities. The objective of this paper was to assess the development and reproduction abilities of T. ( A.) athenas on O. afrasiaticus under laboratory conditions at two temperatures: 27 and 32 °C. The results obtained show that females of T. (A.) athenas develop in 5 days at 27 °C and 4.1 days at 32 °C. The mean fecundity of T. (A.) athenas was 32.1 and 23.2 eggs per female at 27 and 32 °C, respectively. Life table parameters were stimated: the net reproductive rate (Ro) 27.9 and 17.9 eggs/female, the intrinsic rate of increase (rm) 0.322 and 0,344 female/female/day and the mean generation time (T) 10.3 and 8.4 days at 27 and 32 °C, respectively. At both temperatures tested, T. (A.) athenas intrinsic rate of increase was greater than that of O. afrasiaticus (rm = 0.213 at 32 °C,against rm = 0.166 day1 at 27 °C). Typhlodromus (A.) athenas would be able to develop at a wide range of temperatures feeding on O. afrasiaticus and seems to be able to potentially control it.


1983 ◽  
Vol 115 (1) ◽  
pp. 93-105 ◽  
Author(s):  
John V. Boyne ◽  
Fred P. Hain

AbstractExperiments were conducted on Fraser fir, Abies fraseri (Pursh) Poir, seedlings or cut terminals. Results indicate that Oligonychus ununguis (Jacobi) responds most favorably to temperatures approximating 26 °C and to relative humidity levels approaching 50 to 60%. Developmental time, time to 50% mortality, net reproductive rate, mean generation time, intrinsic rate of natural increase, finite rate of increase, and days for populations to double were computed for each temperature and relative humidity regime. Simulated rainfall severely limits population density on Fraser fir seedlings.


2020 ◽  
Vol 25 (8) ◽  
pp. 1373-1383
Author(s):  
Zarir Saeidi ◽  
Alireza Nemati ◽  
Elham Riahi

In the current study, development, reproduction, and longevity of Schizotetranychus smirnovi Wainstein concerning seven different temperatures including 13±1, 15±1, 20± 1, 25±1, 27±1, 30 ±1 and 35 ±1°C, relative humidity 50 ± 10 % and a photoperiod of 14:10 (L:D) h. were investigated. Due to mite inability to settle on leaf disk, almond young branches were used for conducting life table experiments. Our results indicated that higher and lower temperatures caused a steeper decline in survivorship. The highest survival rate was observed at 25 and 27°C. The mean total development time was significantly decreased with increasing the temperatures; while adult longevity for both female and males significantly decreased. Furthermore, offspring production did not occur at 35°C. The highest values of the intrinsic rate of increase (r) and finite rate of increase (λ) were 0.2563 and 1.2922 d-1 at 27°C, while their lowest values were obtained at 13°C. Again high temperature (30°C) caused a decline in both the reproductive rate and growth rate of this mite species. The longest mean generation time (T) (58.55 d) was at 13 °C and it declined significantly with increasing temperature. The most striking result emerging from our data is that 27°C is the most desirable temperature for not only development but also the reproduction of S. smirnovi. Finally, our obtained information provides a better understanding of the life history of S. smirnovi and its ability to survive and reproduce under different temperature regimes which can be used in the management of this pest.


2020 ◽  
Vol 113 (4) ◽  
pp. 1648-1655 ◽  
Author(s):  
Rahim Allahyari ◽  
Shahram Aramideh ◽  
J P Michaud ◽  
Mohammad Hassan Safaralizadeh ◽  
Mohammad Reza Rezapanah

Abstract Cotton bollworm, Helicoverpa armigera Hubner, is a cosmopolitan polyphagous pest of many crops. Habrobracon hebetor Say and Helicoverpa armigera nucleopolyhedrovirus (HearNPV) are two important biocontrol agents used to manage this pest, sometimes in combination. We evaluated the sublethal effects of HearNPV on H. hebetor life table parameters under laboratory conditions when its host (second instar H. armigera) was treated with HearNPV, and tested H. hebetor females for their ability to discriminate against inoculated hosts. Emergence of adults reared as solitary larvae was reduced by half on LC30-inoculated larvae compared to controls, but not on LC5 or LC15-inoculated hosts. Low concentrations (LC5, LC15, and LC30) of HearNPV had no effects on overall parasitoid developmental time, but longevity and lifetime fecundity was reduced for females emerging from hosts receiving the LC30 treatment. Net reproductive rate (R0), intrinsic rate of increase (rm), and finite rate of increase (λ) were all decreased in a concentration-dependent manner in the LC15 and LC30 treatments, as were female life expectancy, age-specific survivorship (lx), and age-specific fecundity (mx), whereas population doubling time (DT) increased. Parasitoids did not discriminate against LC15-inoculated larvae in choice or no-choice tests, but parasitized more LC50-inoculated hosts than controls in the choice test, with no significant differences in total numbers of eggs laid in either case. Although parasitoids suffered some loss of fitness in HearNPV-inoculated hosts under these laboratory conditions, these agents still appear compatible for joint application against H. armigera under field conditions, provided parasitoid releases are made 2 d after NPV application.


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