Longest Mean Generation Time Research Articles

Effect of temperature on the life history and development of Typhlodromus athiasae Porath and Swirski (Acari: Phytoseiidae) as a predator of Tetranychus urticae Koch (Acari: Tetranychidae)

The present study determined the effects of different temperatures on the life history parameters and development of Typhlodromus athiasae Porath and Swirski (Acari: Phytoseiidae) for the first time. The study was conducted at 20, 25 and 30°C and the predators fed on Tetranychus urticae Koch (Acari: Tetranychidae) under laboratory conditions. Our results show that temperature significantly affected pre-adult and adult durations of T. athiasae. The adult longevity was calculated as 47.90, 22.88, 19.50 days for females, 26.11, 19.90, 20.46 days for males at 20, 25 and 30°C, respectively. The adult females of T. athiasae laid 15.80 (eggs/female), 17.20 (eggs/female) and 12.38 (eggs/female) eggs at the respective temperatures tested. The highest net reproductive rate (R0= 8.90 offspring/individual) determined at 25°C but no significant difference was found among the other temperatures. The highest intrinsic rate of increase (r= 0.12 day-1) was observed at 25°C and 30°C. Although the highest finite rate of increase (λ= 1.13 day-1) was determined at 25°C, no significant difference was observed between this temperature and 30°C. Also, the shortest mean generation time (T=14.97 day) was obtained at 30°C whereas the longest mean generation time (T=28.39 day) was observed at 20°C. Our results revealed that 25°C was more suitable for mass production even if the female and male of T. athiasae survived and reproduced at all temperatures. Consequently, our present results and the data to be obtained in greenhouse and field conditions will reveal the potential of T. athiasae as a biological control agent of T. urticae.

Life Table Parameters of Tetranychus merganser Boudreaux (Acari: Tetranychidae) on Five Host Plants.

The quality of the host plant affects the life history parameters of tetranychid mites. The biology and fertility life tables of Tetranychus merganser on five host plants (Carica papaya, Phaseolus vulgaris, Capsicum annuum var. glabriusculum, Helietta parvifolia, and Rosa hybrida) were assessed under laboratory conditions at 28 ± 1 °C and 70-80% relative humidity (RH) with a photoperiod of 12:12 h (L:D). The development period of immature females differed among the tested host plants and ranged from 9.32 days on P. vulgaris to 11.34 days on H. parvifolia. For immature males, it ranged from 9.25 days on P. vulgaris to 11.50 days on H. parvifolia. The female survival rate varied from 53.97% on H. parvifolia to 94.74% on P. vulgaris. The highest total fecundity rate was recorded on P. vulgaris (125.40 eggs/female) and the lowest on H. parvifolia (43.92 eggs/female). The intrinsic rate of increase (rm) varied from 0.271 (H. parvifolia) to 0.391 (P. vulgaris). The net reproductive rate (RO) was higher on P. vulgaris than on the other host plants. The longest mean generation time (GT) was calculated on C. annuum var. glabriusculum and the shortest on Rosa hybrida. The demographic parameters suggest the unsuitability of H. parvifolia as the host for the development of red spider mites, and the best performance of T. merganser was on P. vulgaris.

Performance of Tetranychus urticae (Acari: Tetranychidae) on six cotton varieties with varying degree of leaf pubescence

In this study, we investigated the effect of leaf hairiness, based on non-glandular trichome density, of six cotton varieties (Gloria, Lima, Carla, DP-396, Edessa and ST-468) on the development, reproduction and population parameters of Tetranychus urticae (Acari: Tetranychidae) under controlled conditions. According to trichome densities (mean number/cm2) on the abaxial surface of cotton leaves: Edessa (583.8) and ST-468 (569.9) were grouped as high density; DP-396 (394.9) and Carla (367.5), medium density; Lima (20.4) and Gloria (13.3), low density. As a result, total development periods of T. urticae in Gloria, Lima, Carla, DP-396, Edessa and ST-468 varieties were 9.7, 9.8, 10.6, 10.6, 11.9 and 11.8 days, respectively. The developmental periods of immature stages and total preadults increased significantly with increasing leaf trichome density. The longest oviposition period of T. urticae was detected in Gloria (27.5 days) and Lima (25.1 days) and the shortest was in Edessa (16.4 days) and ST-468 (17.4 days). The highest total fecundity was determined in Gloria (135.6 eggs) and Lima (131.4 eggs) varieties. The highest intrinsic rate of increase (r), finite rate of increase (l) and net reproductive rate (R0) were obtained in Gloria, Lima, Carla and DP-396, the lowest in Edessa and ST-468 varieties. The longest mean generation time (T) was detected in Edessa (19.0 days) and ST-468 (18.6 days). The result of this study showed that cotton varieties with high trichome density negatively affected the development, reproduction and population parameters of T. urticae.

Population growth performance of Panonychus ulmi Koch (Acarina: Tetranychidae) on different fruit trees

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.

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

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.

<p class="Body"><strong>Temperature-dependent development and life table parameters of <em>Schizotetranychus smirnovi</em> (Acari: Tetranychidae) on Almond</strong></p>

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.

Biology and life table analysis of Tetranychus urticae (Acari: Tetranychidae) on different common pea and bean cultivars

The quality of the important host plants affects the survival, development, and reproduction of the two-spotted spider mite, Tetranychus urticae Koch. The biology and life table parameters of T. urticae, on four cultivars of common Regular and Sweet pea and Polesta & G6 bean, were examined under laboratory conditions of 27 ± 1 ℃, 60–80% R.H. and photoperiod 16L: 8D h. Both males and females of T. urticae successfully developed from egg to adult on different host plants. Results revealed that the survival rate varied from 53% on Regular pea to 99% on G6 bean cultivars. The developmental time from egg to adult was significantly influenced among the tested host plant cultivars and ranged from 9.75 days on G6 bean to 20.42 days on Regular pea (p = 0.00). Female longevity was significantly longer on Regular and Sweet pea than on Polesta and G6 bean. The highest fecundity per female was recorded on G6 bean, but the lowest was on Regular pea cultivars. Consequently, population growth parameters were also significantly influenced by different host plants. The net reproductive rate (R0), the intrinsic rate of natural increase (r), and the finite rate of increase (λ) of T. urticae were significantly higher on G6 bean than the other three cultivars. Also, the longest mean generation time (T) and doubling time (DT) were noted on Regular pea, but the shortest value on G6 and Polesta bean cultivars. Obtained results based on the intrinsic rate of natural increase revealed that G6 and Polesta bean were more suitable than the two pea cultivars as hosts for T. urticae. Therefore, the lower population growth rate of the T. urticae could be the result of antibiotic resistance in the cultivars Regular and Sweet pea.

Effect of Eggplant Varieties and Temperatures on Development and Fertility Life Tables of Chrysoperla carnea (steph.) (Neuroptera: Chrysopidae)

An experiment was conducted at the Experimental farm, Faculty of Agriculture, Mansoura University, to evaluate the effect of three eggplant (Solanum melongena L.) varieties (Classic, 0111 and Anan) on development and age-specific fertility life table of the green lacewing predator, Chrysoperla carnea (Steph.) that fed upon the cotton aphid, Aphis gossypii Glover reared at three various temperatures (20, 25 and 30 ± 1˚C) and 60 ± 5% R.H. The results showed that a significant difference among the larval developmental times at the three temperature regimes within each eggplant variety. Similarly, the entire development (egg-adult) of C. carnea was significantly differed among host varieties, hosting aphids, within each temperature regime. For the life table parameters, the highest value of gross reproductive rate (GRR) for C. carnea was obtained when provisioned with aphidsreared on Classic variety at 30˚C. Moreover, the longest mean generation time (T) and doubling time (DT) were achieved when the predator fed upon prey that reared on Anan and 0111 varieties, respectively. Further, the lowest and highest values of the net reproductive rate (Ro) were obtained when the predator provided with prey from Classic and 0111 varieties, respectively. Additionally, the highest value of the intrinsic rate of increase (rm) was obtained when the A. gossypii fed on Classic variety at 30 °C. It can be concluded that both eggplant verities and temperature had significant effects on the developmental time and life table parameters of the predator. Hence, to optimize the mass rearing of A. gossypii as a preferred prey for C. carnea, Classic variety of eggplant has to be considered. As well, the range of temperature between 25-30°C would maximize the performance of predator under rearing conditions. This information on tritrophic interactions and subsequent life table estimates of C. carnea improves IPM programs of aphids.

Comparative life table analysis of Tetranychus urticae Koch (Acari: Tetranychidae) on ten rose cultivars

Life history parameters of plant feeders are useful tools to evaluate resistance or susceptibility of host plants including different cultivars. This study compared population growth parameters of Tetranychus urticae Koch on 10 rose cultivars, including Bella Vita, Cool Water, Dolce Vita, Maroussia, Orange Juice, Pink Promise, Roulette, Tea, Valentine, and Persian yellow in laboratory conditions at 24+/-1°C, 65+/-5% relative humidity, and a photoperiod of 16:8 (L:D) h. The results revealed that mite survival rate varied from 66.5% on Bella Vita to 85.9% on Persian yellow. The immature development time was different among the tested rose cultivars and ranged from 9.35 days on Orange Juice to 12.30 days on Bella Vita. The highest fecundity rate was recorded on Pink Promise. Consequently, population growth parameters were also significantly affected. The lowest intrinsic rate of increase (rm) was recorded on Roulette and this parameter was relatively higher on Cool Water, Orange Juice, and Persian yellow. In addition, the highest net reproductive rate (R0) was observed on Pink Promise, which was significantly higher than Roulette, Tea, and Valentine cultivars. The longest mean generation time (T) was calculated on Roulette and the shortest on Cool Water, Tea, and Orange Juice. The lowest performance of the two-spotted mite on Roulette could indicate that this is a suitable cultivar against mite infestation. Differences in mite susceptibility of tested rose cultivars here highlighted have the potential to be used for integrated pest management of T. urticae in ornamental rosa cultivations.

Population Growth Parameters of Rose Aphid, Macrosiphum rosae (Hemiptera: Aphididae) on Different Rose Cultivars.

The rose aphid, Macrosiphum rosae (L.), is one of the most important pests on rose plants (Rosa spp.) with a worldwide distribution. As resistance indices, the development, survivorship, and reproduction of this aphid were evaluated on 10 rose cultivars, including Bella Vita, Cool Water, Dolce Vita, Maroussia, Orange Juice, Pinkpromise, Roulette, Tea, Valentine, and Persian Yellow in laboratory at 25 ± 1°C, 65 ± 5% relative humidity, and photoperiod of 16:8 (L/D) h. Rose aphid successfully survived on all 10 rose cultivars, although mortality rate was higher on Tea and Bella Vita. The number of offspring per female differed significantly among the tested rose cultivars, and ranged from 9.2 on Tea to 38.7 nymphs on Orange Juice. Population growth parameters were significantly affected by rose cultivars. The longest mean generation time (T) was observed on Bella Vita (14.8days) and Tea (14.7days) and the shortest on Orange Juice (10.0days). The net reproductive rate (R 0 ) ranged from 6.9 on Tea to 33.2 nymphs on Orange Juice cultivar. Correspondingly, the highest value of intrinsic rate of increase (r m ) was observed on Orange Juice (0.348day-1) and lower values on Tea (0.131day-1) followed by Bella Vita (0.154day-1). Cluster analysis of all the measured parameters of rose aphid on different rose cultivars revealed that Tea and Bella Vita were relatively resistant to M. rosae. These findings could be useful in developing an integrated pest management (IPM) program for this aphid in urbanized areas and commercial rose potting.

Effects of Chemical, Organic and Bio-Fertilizers on Some Secondary Metabolites in the Leaves of Bell Pepper ( Capsicum annuum ) and Their Impact on Life Table Parameters of Myzus persicae (Hemiptera: Aphididae).

The green peach aphid, Myzus persicae (Sulzer), is a polyphagous and a holocyclic aphid that causes severe damage on hundreds of host plants in both fields and greenhouses. In this research, the effects of Zinc sulfate spray and amending the soil with 30% vermicompost, Bacillus subtilis , Pseudomonas fluorescens , Glomus intraradices , G. intraradices × B. subtilis , and G. intraradices × P. fluorescens compared with no fertilizer treatments were investigated on secondary metabolites in the leaves of bell pepper and life table parameters of M. persicae . Total phenol contents in the plant leaves varied significantly among different fertilizer treatments. The highest (72.28 mg/ml) value was observed on 30% vermicompost. Life table parameters of M. persicae were significantly affected by different fertilizer treatments. The net reproductive rate ( R 0 ) of M. persicae fed on plants treated with different fertilizer treatments varied from 4.38 to 21.93 female offspring, with the lowest and highest values on 30% vermicompost and Zinc sulfate, respectively. The lowest and the highest intrinsic rate of increase ( r m ) were also observed on 30% vermicompost and Zinc sulfate (0.111 and 0.321 female per female per day, respectively). The longest mean generation time ( T ) was recorded on 30% vermicompost (13.41 d), and the shortest generation time was observed on Zinc sulfate (9.61 d). Results of this study revealed that amending the soil with 30% vermicompost significantly affected the life table parameters of M. persicae . Thus, it was concluded that amending the soil of bell pepper with 30% vermicompost can provide an environmentally safe and efficient control of this aphid.

Demography of pistachio fruit hull borer moth, Arimania komaroffi (Lepidoptera: Pyralidae) under different constant temperatures

Recently, the pistachio fruit hull borer moth, Arimania komaroffi Ragonot (Lepidoptera: Pyralidae) has been emerged as a major pest of pistachio in Iran. Temperature is the most effective ecological factors on demography and life cycle of arthropods. The effect of temperature on the reproduction and population growth parameters of this pest was investigated in current study. Experiments were conducted at four constant temperatures 25, 27.5, 30 and 32.5 (±1) °C, on Ohadi cultivar in the laboratory. Based on the results, the immature development times were calculated as 56.37±0.53, 47.72±0.70, 42.03±0.39 and 39.10±0.46days at 25, 27.5, 30 and 32.5°C, respectively. The highest net fecundity rate was 25.34 eggs/female at 27.5°C, although no significant difference was observed between 27.5 and 30°C. Mean daily number of eggs laid by a female was the greatest at 30°C. The gross reproductive rate (GRR) and net reproductive rate (R0) of A. komaroffi were higher at 30 and 27.5°C. The highest intrinsic rate of increase (rm) was calculated as 0.056 at 30°C. Similarly no significant difference was observed in rm values between 27.5 and 30°C. The higher finite rates of increase (λ) ware achieved at 27.5 and 30°C. The longest mean generation time (T) was 59.9days at 25°C. Pest generation time decreased significantly with increasing temperature from 25°C to 30°C. Regarding the results, development and population increase of A. komaroffi at 27.5 and 30°C were more rapidly performed and this knowledge could be valuable in its monitoring and control.

Life history of Proprioseiopsis badri feeding on four eriophyid mite species (Acari: Phytoseiidae and Eriophyidae)

The influence of four eriophyid mite species as prey, Aceria dioscoridis, Aceria olivi, Aculops lycopersici and Cisaberoptus kenyae, on the biology and demographic parameters of the predatory mite Proprioseiopsis badri, was studied under laboratory conditions. Feeding on A. dioscoridis and A. olivi enhanced the development of P. badri, resulted in the longest mean generation time and were the most suitable foods for the oviposition of the predator, as exhibited by the highest fecundity, net reproductive rate and gross reproductive rate. Preying on A. lycopersici gave the lowest fecundity, net and gross reproductive rates and finite rate of increase; therefore, this prey was the least suitable for the oviposition of P. badri. Preying on A. dioscoridis and A. olivi produced higher intrinsic rates of increase, reproduction rates and finite rates of increase for the predator in comparison with A. lycopersici and C. kenyae, which had the lowest value. These differences in response to various eriophyid pests should be considered for the production of healthy cultures of P. badri.

Life Table and Population Parameters ofSchizaphis graminum(Rondani) (Hemiptera: Aphididae) on Six Wheat Genotypes

ABSTRACT: Biological parameters of Schizaphis graminum (Rondani) reared on an ancient wheat species (Einkorn) from England and five Iranian wheat genotypes (Azadi, Ommid, Marvdasht, Pishtaz and Moghan 2) were studied under controlled conditions at 22 ± 1°C, 65 ± 5% RH, 16:8 (L:D) h. The lowest rm value (0.261± 0.002 females/female/day) and net reproductive rate (R0) (28.747± 0.369) were recorded on Einkorn. The highest and the lowest finite rates of increase (λ) were on Moghan 2 and Einkorn, respectively. Also, the longest mean generation time (T) and doubling time (DT) with the lowest percentages of nymphal survival (79.5%) and fecundity over developmental time (35.739± 0.378 nymphs/female/day) were obtained on Einkorn. Adult longevity varied from 10.72± 0.123 days on Einkorn to 18.04± 0.212 days on Moghan 2. Therefore, our results showed that Einkorn, exerting a high level of antibiosis compared to other tested genotypes, may decrease the population density of the greenbug.

Life history of Sancassania polyphyllae (Acari: Acaridae) feeding on dissected tissues of its phoretic host, Polyphylla fullo (Coleoptera: Scarabaeidae): temperature effects

The effect of temperature on the development and fecundity of Sancassania polyphyllae fed on tissues of Polyphylla fullo larvae was studied at 15, 20, 25, 30, and 35±1°C and 65±10% RH in a dark incubator. Mean developmental period of immature stages decreased significantly with increasing temperatures from 15 to 30°C. Developmental periods at 30-35°C were not significantly different. The estimated lower developmental thresholds of the various immature stages ranged between 10.1 and 11.5°C. The thermal constant for the egg-to-female adult was 93.5 degree-days. The pre-oviposition, oviposition, and post-oviposition periods and female longevity were significantly longer at 15°C than at higher temperatures. Mean total and daily fecundity were the highest at 25°C, which were significantly different from those obtained at 15, 20 and 30°C. The net reproductive rate (R (0)) was the highest at 25°C (588.3 ♀/♀). The longest mean generation time (T (0)) occurred at 15°C (36days) and the shortest occurred at 30°C (9.2days). The highest intrinsic rate of increase (r (m)) for S. polyphyllae was observed at 25 (0.61 ♀/♀/day) and 30°C (0.62 ♀/♀/day).

Development and reproduction of Sancassania polyphyllae (Acari: Acaridae) feeding on entomopathogenic nematodes and tissues of insect larvae

Abstract We studied the effect of different food sources, infective juveniles of the entomopathogenic nematodes, Steinernema feltiae and Heterorhabditis bacteriophora (Rhabditida: Steinernematidae, Heterorhabditidae), and tissues from the insect larva, Polyphylla fullo (Coleoptera: Scarabaeidae) or Galleria mellonella (Lepidoptera: Pyralidae), on the development, reproduction and longevity of Sancassania polyphyllae (Acari: Acaridae). We showed that the immature mite stages – protonymph and tritonymph – could develop to the next developmental stage on living or sonicated (i.e., ruptured) S. feltiae or H. bacteriophora. However, the mite larval stage could only develop to the next developmental stage on sonicated infective juveniles of the nematodes. Subsequently, we demonstrated that S. polyphyllae completed development from protonymph to adult on live S. feltiae or H. bacteriophora, whereas all immature stages of S. polyphyllae completed their development from larva to adult on insect tissues. The total developmental period of S. polyphyllae that fed on insect tissues was significantly shorter than those that fed on live infective juveniles. The pre-oviposition, oviposition, and post-oviposition periods and female longevity were not significantly different among the food sources. The total and daily fecundity of S. polyphyllae feeding on P. fullo and G. mellonella was significantly higher than those feeding on S. feltiae and H. bacteriophora, although there was no significant difference observed between P. fullo and G. mellonella or between S. feltiae and H. bacteriophora. The net reproductive rate (R0) was highest (588.3♀/♀) when S. polyphyllae fed on P. fullo. The longest mean generation time (T0) occurred on H. bacteriophora (12.6 days) and the shortest occurred on P. fullo (10.5 days). S. polyphyllae, which fed on P. fullo (rm=0.61) and G. mellonella (rm=0.55) had the highest intrinsic rate of increase (rm) compared to mites that fed on S .feltiae (rm=0.45) and H. bacteriophora (rm=0.41).

Tabelas de esperança de vida e fertilidade para Lipaphis erysimi (Kalt.) (Hemiptera: Aphididae) em condições de laboratório e campo

Depto. Fitossanidade FCAV/UNESP, via de acesso Paulo Donato Castellane s/no, 14870-000, Jaboticabal, SP

Comparative Survival and Demographic Statistics for Wild Oriental Fruit Fly, Mediterranean Fruit Fly, and Melon Fly (Diptera: Tephritidae) on Papaya

Oriental fruit fly, Dacus dorsalis Hendel; melon fly, Dacus cucurmtae Coquillett; and Mediterranean fruit fly, Ceratitis capitata (Wiedemann) were reared from hosts collected within 40km of papaya, Carica papaya L., orchards. Survivorship and demographic statistics were compared for experimental F1 populations established on papaya fruit under controlled laboratory conditions. C. capitata, D. dorsalis , and D. cucurmtae females survived a maximum of 109, 123, and 222 d, respectively. C. capitata , with the shortest mean generation time ( T = 39.9 d) and the highest net reproductive rate ( Ro = 173.3), had the highest intrinsic rate of increase ( rm = 0.13). D. dorsalis , with the second longest mean generation time ( T = 62.2 d) and the second highest net reproductive rate ( Ro = 167.2), had the second highest intrinsic rate of increase ( rm = 0.09). D. cucurmtae , with the longest mean generation time ( T = 71.7 d) and the lowest net reproductive rate ( Ro = 80.8), had the lowest intrinsic rate of increase ( Rm = 0.06). Results are discussed with respect to development of population management strategies in papaya orchards in Hawaii and eradication of fruit flies accidentally introduced into the U.S. mainland.