Bioecology of the tea thrips, Scirtothrips bispinosus Bagnall (Thysanoptera: Thripidae) infesting tea in south India

ENTOMON ◽  
2019 ◽  
Vol 44 (3) ◽  
pp. 161-172
Author(s):  
P. Mahendran ◽  
B. Radhakrishnan

Investigations were carried out on the life history and seasonal abundance of the thrips, Scirtothrips bispinosus infesting tea at Coonoor, The Nilgiris, Tamilnadu. The total developmental duration of females from egg to adult stage was 18.15±0.23, 12.55±0.15 and 10.30±0.23 days at 20, 25 and 30oC respectively. The net reproductive rate (Ro), mean generation time (Tc), intrinsic rate of natural increase (rm), finite rate of increase (ë) and weekly multiplication (Wm) rates were high at 25oC followed by 30oC and 20oC. Multiple regression analysis revealed that population density of S. bispinosus showed a negative relationship with rainfall (-0.266), maximum temperature (-38.839) and maximum relative humidity (-3.356) and positive relationship with minimum temperature (63.205), minimum relative humidity (1.686) and sunshine period (2.887). Incidence of thrips was high in the fields recovering from pruning followed by second, third and fourth year in a pruning cycle. The number of thrips per shoot was significantly higher on the plucking table when compared to the shoots present below the plucking table and side branches. In the tea plantations of South India, four species of predatory mites (Amblyseius cucumeris, A. fallacies, A. degenerans and Balaustium sp.), two species of predatory thrips (Franklinothrips vespiformis and Leptothrips mali), an anthocorid predator (Orius sp.) and one parasitoid (Trichogramma sp.) were found feeding and parasitizing on tea thrips, S. bispinosus.

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.


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.


Biology ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 72
Author(s):  
Jun Jiang ◽  
Li-Li Xu ◽  
Wen-Yuan Yu ◽  
Shi-Ze Zhang ◽  
Tong-Xian Liu

Bemisia tabaci and the diamondback moth (DBM), Plutella xylostella, are two major cosmopolitan pests that often occur together and cause severe economic losses to cruciferous crops. However, little is known about how they interact with each other. To determine the effects of defense responses induced by the two pests on the biology and population dynamics of the herbivores, we studied the performance and fitness of B. tabaci and DBM when they damaged Chinese kale simultaneously and in different orders. The results showed that DBM pre-infestation shortened the developmental duration, increased longevity, oviposition days, and fecundity of B. tabaci. Meanwhile, the intrinsic rate of increase (r), net reproductive rate (R0) and finite rate of increase (λ) of B. tabaci increased significantly with dual infection as compared with only B. tabaci infestation. In contrast, B. tabaci pre-infestation reduced the longevity and oviposition days of DBM, but the population parameters r, R0, and λ did not vary significantly compared with only DBM infestation. Thus, co-infestation of B. tabaci and DBM was beneficial to the performance of the B. tabaci population. The present findings highlight that B. tabaci has become a dominant competitor when mixing with DBM on the same host plant.


2021 ◽  
Vol 25 (02) ◽  
pp. 460-468
Author(s):  
Muhammad Farooq

The sucking pests, especially whitefly, have damaged various fields and fruit crops across the globe. The study of life-history is of prime importance to monitor the dynamics for preference of a species to its host. This study tested the prevalence and preference of a whitefly species, Bemisia tabaci (Gennadius) B biotype (Hemiptera: Aleyrodidae) on tomato, cotton, pepper, and okra as hosts using age-stage two-sex life table. Results revealed the highest pre-adult developmental duration, survival rate, and fecundity on tomato while the lowest values on okra. Population parameters such as the net reproductive rate (R0), intrinsic rate of increase (r), and finite rate of increase (λ) were demonstrated longer on cotton and tomato compared to much lower R0, r, and λ on pepper and okra. Okra responded significantly differently in the case of the mean generation time, T among all tested genotypes. These findings suggest the possibility of summer vegetables as more favorable hosts for B. tabaci. © 2021 Friends Science Publishers


2014 ◽  
Vol 1 (1) ◽  
pp. 18-29
Author(s):  
Saeid Javadi Khederi ◽  
Mohammad Khanjani

The demographic parameters of brown mite, Bryobia rubrioculus Scheuten were carried out in order to characterize the population growth potential at five constant temperatures: 20, 22.5, 25, 27.5 and 30ºC, 60 ± 5 % RH and 16: 8 (L: D) h. The highest intrinsic rate of natural increase (rm = 0.0243/day), net reproductive rate (R0 = 2.4 ♀/♀/T) and finite rate of increase (λ = 1.0245 day-1) values were determined at 22.5°C. The mean generation time (T) of the population ranged from 22.7 days at 30°C to 45.8 days at 20°C. The maximum and minimum survival rates (lx) were recorded at 22.5ºC and 30ºC. Survivorship data (lx) of adult females were summarized and compared using the shape and scale parameters of the Weibull frequency distribution model across. The age specific fecundity data (mx) was modeled as a function of time by using Polynomial model. The lower temperature threshold (t) and thermal constant (k) of the immature stages were estimated using Ikemoto and Takai linear model to be 12.85ºC and 279.7 degree days (DD), respectively. Of the non-linear models, the Analitis-1, Analitis-2, Analitis-3 and Analitis/Allahyari models were found to be the best for the modeling development rate of immature stages of B. rubrioculus. The optimal temperature for population growth of brown mite on apple was found at 22.5°C.


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.


FLORESTA ◽  
2016 ◽  
Vol 46 (2) ◽  
pp. 251
Author(s):  
Josiane Teresinha Cardoso ◽  
Sonia Maria Noemberg Lazzari

Biological parameters of Pineus boerneri were evaluated in laboratory using seedlings of Pinus taeda and Pinus elliottii. The nymphs were observed along their development. The total life cycle was not significantly different on P. taeda and P. elliottii, being, respectively, 69 and 65 days. The same trend was observed for mean fecundity, being about 40 eggs/female on P. taeda and 53 on P. elliottii. However, when daily mean fecundity was considered, the difference was significant, being 1.3 eggs/female/day on P. taeda and 1.8 on P. elliottii. The nymphal mortality was greater on P. taeda (50%) than on P. elliottii (28%). These results reflected on life expectancy which was higher on P. elliottii for the nymphal stage, but for the adult stage there was no significant difference between both host plants. The intrinsic rate of natural increase and the finite rate of increase were similar, indicating that P. boerneri shows the same reproductive capacity on both hosts, despite the net reproductive rate being much greater on P. elliottii (23.8 eggs/female) than on P. taeda (15.4). The highest nymphal survival and reproductive rates on P. elliottii indicate that this host plant is more suitable for the development of P. boerneri.


1970 ◽  
Vol 16 ◽  
pp. 25-28
Author(s):  
MM Rahman ◽  
W Islam ◽  
KN Ahmed

Plastanoxus westwoodi is an efficient ectoparasitoid of larvae and pupae of the red flat grain beetle Cryptolestes pusillus. Fertility life tables and effects of host instar on life table parameters of P. westwoodi on C. pusillus were studied in the laboratory. Generally adult females lived for 13-16 days. Oviposition commenced on the 1st day of adult emergence and continued till death or 1-2 days before the death of a parasitoid. The intrinsic rate of natural increase (rm) was found to be 0.2291 per female per day. The net reproductive rate (R0) was 64.07; the innate capacity for increase (rc) was 0.2096. The finite rate of increase (λ) was calculated as 1.4735 per female per day, while corrected generation time (T) was computed as 18.16 days. Key words: Plastanoxus westwoodi, Cryptolestes pusillus, Oviposition, Life table, Biological control   DOI:10.3329/jbs.v16i0.3737    J. bio-sci. 16: 25-28, 2008   


2004 ◽  
Vol 94 (4) ◽  
pp. 377-384 ◽  
Author(s):  
W.T.S.D. Premachandra ◽  
C. Borgemeister ◽  
A. Chabi-Olaye ◽  
H.-M. Poehling

AbstractCeratothripoides claratris (Shumsher) is a serious pest attacking tomatoes in Thailand. Temperature-dependent development of C. claratris was studied at seven constant temperatures, i.e. 22, 25, 27, 30, 34, 35 and 40°C. Pre-adult survivorship was greatest (95%) at 25 and 30°C and shortest at 22°C. Egg-to-adult time decreased within the range of 20 to 30°C and at 34°C it started to increase. The lower thermal threshold for egg-to-adult development was estimated at 16 and 18°C by linear regression and the modified Logan model, respectively. The optimum temperature for egg-to-adult development was estimated at 32–33°C by the modified Logan model. The influence of temperature on reproduction and longevity of C. claratris was determined at 25, 30 and 35 and 40°C. Both inseminated and virgin females failed to reproduce at 40°C. Virgin females produced only male offspring, confirming arrhenotoky. The sex ratio of the offspring of fertilized females was strongly female-biased, except at 25°C. Mean total fecundity per female and mean daily total fecundity per female were highest for both virgin and inseminated females at 30°C. Female longevity was longest at 25°C and shortest at 40°C. Male longevity was longest at 30°C and shortest at 40°C. The net reproductive rate (R0) and intrinsic rate of natural increase (rm) was greatest at 30°C while, mean generation time (G) and the doubling time (t) were highest at 25°C. The finite rate of increase (λ) was fairly constant (1.1–1.5 days) over the three temperatures tested. The pest potential of C. claratris for tropical Asia is discussed.


2020 ◽  
Vol 110 (5) ◽  
pp. 620-629
Author(s):  
Hajar Pakyari ◽  
Mark R. McNeill

AbstractThe effect of five photoperiods (0:24, 6:18; 12:12, 18:6, and 24:0 light:dark (L:D)) on the development, reproduction, and survival of the predatory thrips Scolothrips longicornis Priesner fed on the two-spotted spider mite, Tetranychus urticae Koch, was tested under laboratory conditions at 60% RH and 25°C. Development time of almost all immature stages in S. longicornis was the shortest under long day lengths (18:6 and 24:0 L:D). The adult duration of both sexes decreased with increasing light length from 6 to 24 h. The longevity of male and female decreased with increasing light length. Under a 12:12 L:D photoperiod, S. longicornis females had the longest oviposition period and longevity, highest net reproductive rate (R0 = 15.37), intrinsic rate of natural increase (r = 0.141), and finite rate of increase (λ = 1.151). Life table parameters showed a significant difference with various photoperiods. The consequences of the present research demonstrated that a 12:12 L:D photoperiod is the most favorable for the reproduction and development of S. longicornis fed on T. urticae, and that for mas rearing for augmentative biological control programs, would be the ideal photoperiod to maximize production.


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