REPRODUCTION AND POPULATION GROWTH OF THE PEA APHID (HOMOPTERA: APHIDIDAE) UNDER LABORATORY AND FIELD CONDITIONS

1977 ◽  
Vol 109 (2) ◽  
pp. 277-284 ◽  
Author(s):  
A. Campbell ◽  
M. Mackauer

AbstractThe effect of temperature on the age-specific fecundity and the survival of apterous and alate virginoparous pea aphid, Acyrthosiphon pisum (Harris), from Kamloops, B.C., was measured. Demographic statistics were estimated for 10.3°, 14.8°, 19.7°, 26.1°, and 27.8°C constant and for fluctuating field temperatures. On a 24-h-day time-scale, temperature and longevity were inversely related in both morphs; total fecundity was highest at average and low constant temperatures. On a physiological time-scale, the intrinsic rate of increase (rm) was insensitive to changes in constant temperature in the range between 10° and 20°C; temperatures above 25°C were detrimental to aphid population growth and survival. Alate virginoparae generally had a longer pre-reproductive period and achieved a lower mean total fecundity than apterae maintained under identical conditions. The usefulness of laboratory measurements for the prediction of population growth under variable field temperatures is discussed. Differences in the reproductive patterns of alate and apterous pea aphids are considered in the context of the r- and K-hypothesis of selection.

1975 ◽  
Vol 107 (9) ◽  
pp. 919-926 ◽  
Author(s):  
A. Campbell ◽  
M. Mackauer

AbstractParasitism by Aphidius smithi reduced the fecundity and population growth of pea aphid, Acyrthosiphon pisum. Aphids that were parasitized during the first or second instar period died as fourth instars without producing offspring. Parasitized third or fourth instars usually reached maturity and produced a variable number of progeny. Parasitized adult aphids stopped producing nymphs approximately 7 to 8 days following attack by A. smithi. Equations are given for the relationship between the mean total fecundity, the intrinsic rate of increase, and the doubling time of apterous and alate viviparous pea aphid and the aphid age at the beginning of parasitism.


2017 ◽  
Vol 108 (1) ◽  
pp. 84-92 ◽  
Author(s):  
A.M. Hamada ◽  
J. Fatehi ◽  
L.M.V. Jonsson

AbstractThiamine is a vitamin that has been shown to act as a trigger to activate plant defence and reduce pathogen and nematode infection as well as aphid settling and reproduction. We have here investigated whether thiamine treatments of seeds (i.e. seed dressing) would increase plant resistance against aphids and whether this would have different effects on a generalist than on specialist aphids. Seeds of wheat, barley, oat and pea were treated with thiamine alone or in combination with the biocontrol bacteriaPseudomonas chlororaphisMA 342 (MA 342). Plants were grown in climate chambers. The effects of seed treatment on fecundity, host acceptance and life span were studied on specialist aphids bird cherry-oat aphid (Rhopalosiphum padiL.) and pea aphid (Acyrthosiphon pisumHarris) and on the generalist green peach aphid (Myzus persicae, Sulzer). Thiamine seed treatments reduced reproduction and host acceptance of all three aphid species. The number of days to reproduction, the length of the reproductive life, the fecundity and the intrinsic rate of increase were found reduced for bird cherry-oat aphid after thiamine treatment of the cereal seeds. MA 342 did not have any effect in any of the plant-aphid combinations, except a weak decrease of pea aphid reproduction on pea. The results show that there are no differential effects of either thiamine or MA 342 seed treatments on specialist and generalist aphids and suggest that seed treatments with thiamine has a potential in aphid pest management.


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. 


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.


2014 ◽  
Vol 14 (1) ◽  
pp. 64-70
Author(s):  
Nila Wardani ◽  
Aunu Rauf ◽  
Wayan Winasa ◽  
Sugeng Santoso

ABSTRACTThe life history and population growth parameters of mealybug Phenacoccus manihoti Matile-Ferrero (Hemiptera: Pseudococcidae) on two cassava varieties. The development, reproduction, and population growth parameters of the cassava mealybug, Phenacoccus manihoti Matile-Ferrero (Hemiptera: Pseudococcidae) on two cassava varieties were studied in laboratory. The varieties tested were UJ-5 with high cyanide content (>100 mg per kg) dan Adira-1 with low cyanide content (27.5 mg per kg).  Our research revealed that P. manihoti performances were highly affected by cassava varieties.  Incubation period of eggs of P. manihoti were 7.93 ±  0.09 and 8.33 ± 0.11 days, nymphal development periode 12.32±0.13 and 15.67 ± 0.13 days, respectively on UJ-5 and Adira-1. Fecundity averaged 386.37 ± 5.83 on UJ-5 and 318.67±2.81 eggs on Adira-1. Intrinsic rate of increase (rm) were  0.258 ± 0.001 on UJ-5 and  0.220 ± 0.001 on Adira-1. Mean generation time (T) on UJ-5 and Adira-1 were 22.795 ± 0.050 and 25.532 ± 0.047 days, repectively. Our findings showed that variety UJ-5 was more suitable for development and population growth of the cassava mealybug.


2020 ◽  
Vol 25 (11) ◽  
pp. 2063-2076
Author(s):  
Nuwan Weerawansha ◽  
Qiao Wang ◽  
Xiong Zhao He

Tetranychus ludeni Zacher (Acari: Tetranychidae) is an invasive polyphagous haplodiploid pest mite of many vegetable crops in many parts of the world. This study investigated the effects of simultaneous variations in the local foundress population density and size on the reproduction and population growth of T. ludeni. We show that negative population-density and -size dependency limited the reproduction of foundresses, where the effects of population size on population growth overweighed that of population density. We further demonstrate that ovipositing females could accelerate population growth rate (intrinsic rate of increase, rm) at higher population sizes by producing more daughters early during their lifespan, which can be an adaptive strategy to allow more daughters to complete development and disperse to reduce future food competition intensity. This study provided knowledge on population dynamics in response to foundress population density and size in general and T. ludeni population forecast and precise timing of pest management in particular.


2021 ◽  
Vol 01 ◽  
Author(s):  
Martin John Martin ◽  
Zuqing Hu ◽  
Zhiqiang Lu

Background: Pea aphids (Acyrthosiphon pisum) possess a weak immune system, but they can firmly mount immunological responses. However, the influence of different plants on their defense against different microbes remains largely unknown. In addition, no previous research has integrated the growth, reproduction, and defense responses of pea aphids feeding on different plants. Objective: This study aims to investigate the growth, reproduction, and defense responses of pea aphids feeding on different plants. Methods: Pea aphids were cultivated on both Medicago sativa and Vicia faba. Growth and reproduction were evaluated. Additionally, we monitored the survival and microbial loads of pea aphids after bacterial and fungal infections. Results : Pea aphids reared on M. sativa had lower growth, lower intrinsic rate of increase, and lower finite rate of increase when compared to aphids feeding on V. faba. The net reproduction was lower in aphids feeding on M. sativa, although the difference was not significant. The mean time of generation and pre-reproductive periods was longer for aphids reared on M. sativa than for aphids reared on V. faba. In the infection experiments, we found that aphid survival was not affected by the host plant. However, A. pisum reared on M. sativa generally harbored fewer microbial loads than those reared on V. faba. Conclusions: The growth and reproduction of pea aphids are affected by the host plant. Aphids feeding on different plants had different tolerances to microbial infections. Our study sheds light on improving biological control programs for aphids.


2021 ◽  
Vol 26 (2) ◽  
pp. 496-508
Author(s):  
Firdevs Ersin ◽  
Ferit Turanli ◽  
Ibrahim Cakmak

Typhlodromus recki (Acari: Phytoseiidae) was collected from aubergines, pepper, black nightshade and jimsonweed plants infested with spider mites from a pesticide-free vegetable garden in Denizli, Turkey. The biology and life table parameters for T. recki feeding on Tetranychus urticae (Acari: Tetranychidae) at different temperatures (15, 20, 25, 30 and 35 °C) were determined. The results showed that total preadult periods of T. recki at 15, 20, 25, 30 and 35 °C were 19.6±0.51, 9.4±0.16, 7.6±0.14, 5.7±0.14 and 4.5±0.08 days, respectively. The longest oviposition period was 23.5 days at 20 °C. Total fecundity of T. recki significantly differed between the constant temperatures and the highest was observed at 20 °C (28.6 eggs/female) and 25°C (23.5 eggs/female). Although females survived for 26 days at 35 °C, only four females laid eggs for 1 day. Thus, 35 °C is not suitable for the reproduction of T. recki. Total longevity of female was the longest at 15°C (59.5 days) and 20 °C (51.3 days) whereas male total longevity was the longest at 15°C (53.2 days). The intrinsic rate of increase (r) and finite rate of increase (λ) were numerically the highest at 30 °C (0.17 and 1.18 d-1), but there was no statistical difference observed between 25 and 30 °C for both r and λ values. The net productive rate was significantly highest at 20, 25 and 30 °C. The longest mean generation time occurred at 15 °C (42.6 days) and the shortest was at 35 °C (8.0 days). After some field trials, Typhlodromus recki could potentially be considered in the biological control agent of T. urticae.


2006 ◽  
Vol 96 (3) ◽  
pp. 305-314 ◽  
Author(s):  
A. Kalyebi ◽  
W.A. Overholt ◽  
F. Schulthess ◽  
J.M. Mueke ◽  
S. Sithanantham

AbstractThe life table statistics of six native Kenyan species/strains ofTrichogrammaandTrichogrammatoideawere established using a factitious hostCorcyra cephalonica, Stainton (Lepidoptera: Pyralidae), at eight different temperatures (10, 15, 20, 25, 28, 30, 32 and 35°C) and two humidity levels (40–50 and 70–80%). The objective was to select insects with superior attributes for augmentative release against lepidopteran pests in horticultural crops. Both temperature and humidity affected developmental time and life table parameters of the parasitoids but temperature played a more critical role. Developmental time was inversely related to temperature. The intrinsic and finite rates of increase increased with temperature up to 30°C. Both net reproduction rate and intrinsic rate of increase were higher at the lower humidity. Temperature inversely affected generation time of parasitoid strains regardless of the relative humidity. Two strains ofTrichogrammasp. nr.mwanzaicollected from both low and medium altitudes andTrichogrammatoideasp. nr.luteafrom the mid-altitudes, were better adapted to both low and high temperatures than the other strains, as indicated by the high intrinsic and net reproductive rates, at both humidity levels. These three strains appear to be promising candidates for augmentation biocontrol against the African bollwormHelicoverpa armigerain Kenya.


1974 ◽  
Vol 25 (3) ◽  
pp. 351 ◽  
Author(s):  
RJ Rippingale ◽  
EP Hodgkin

The intrinsic rate of increase of an animal population can be calculated from data on longevity, sex ratio, maturation rate and fecundity and can be expressed as r in the population growth equation Nt = N0ert. Laboratory and field data are used to calculate the value of r per day for the copepod Gladioferens imparipes Thomson. The r values obtained, 0.146 per day at 15� C and 0.293 per day at 25� C, are both high. This high population growth potential is interpreted as an adaptation to the estuarine habitat.


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