RESISTANCE TO APHIS CRACCIVORA (HOMOPTERA:APHIDIDAE) IN SELECTED VARIETIES OF COWPEA

1985 ◽  
Vol 20 (2) ◽  
pp. 263-269 ◽  
Author(s):  
Frank J. Messina ◽  
J. A. A. Renwick ◽  
Joyce L. Barmore

Nearly 200 varieties of cowpea, Vigna unguiculata (L.) Walp, were screened for resistance to the cowpea aphid, Aphis craccivora Koch. Three varieties known to be resistant in West Africa were highly susceptible to an aphid population from the southern United States. Four other varieties, however, inhibited growth of the southern United States population both in the laboratory and in the field. Life-table comparisons using a resistant and a susceptible variety revealed a three-fold difference in the intrinsic rate of increase and a more than twenty-fold difference in the net reproductive rate. High nymphal mortality and low fecundity on resistant plants were largely responsible for these differences.

2013 ◽  
Vol 53 (3) ◽  
pp. 253-262 ◽  
Author(s):  
Khadijeh Madahi ◽  
Ahad Sahragard ◽  
Reza Hossieni

Abstract The life table provides an integrated and comprehensive description of development times, survivorship, and reproduction of a population. Life table parameters of aphidophagous midge, Aphidoletes aphidimyza Rondani (Dip., Cecidomyiidae) on different densities (5, 10, 20, 40, 60, 80) of third instar nymphs of Aphis craccivora Koch as prey, were studiedat (25±1°C, 70±5% relative humidity (RH) and a photoperiod of 16L : 8D h). There were no significant differences among the adult pre-ovipositional periods (APOP) at different prey densities. The total pre-ovipositional period (TPOP) of female A. aphidimyza was reduced significantly as prey density increased. The oviposition period was significantly different at varying prey densities. It was 4.333±0.211 and 5.625±0.324 days at the lowest and highest prey densities, respectively. Female longevity was also significantly different at varying prey densities. Fecundity was directly dependent on prey density (R2 = 0.990). The lowest fecundity was obtained at a density of 5 prey (52.5±1.544 eggs) and the highest was at a density of 80 prey, per day (121.375±4.301 eggs). The intrinsic rate of increase (r) was prey density dependent (R2 = 0.958), and ranged from 0.122±0.017 to 0.193±0.014 d-1 as prey density increased. The net reproductive rate (R0) was significantly increased as prey density increased. The peak reproductive values showed that female aphidophagous midges at the age of 15, 16, 17, 18, and 19 days made the highest contribution to the population at different prey densities. It was concluded that the increase in the densitits of third instar nymphs of A. craccivora had significant effects on demographic parameters of A. aphidimyza


2021 ◽  
Author(s):  
Eman Fouad ◽  
Sherifa A.N. El-Sherif ◽  
El-Sayed M. S. Mokbel

Abstract Insecticide induced-hormesis, a biphasic phenomenon ,with low-dose stimulation and high-dose inhibition, which effectively contributes to pest resurgence. Although cowpea aphid, Aphis craccivora (Koch) (Homoptera: Aphididae), is the most infection insect to legume crops in Egypt, its’ hormesis to flupyradifurone did not previously establish. Therefore, age-stage two-sex life analysis was used to investigate the sublethal and transgenerational effects of flupyradifurone on two successive generations of A. craccivora. Leaf-dip bioassay method revealed high toxicity of flupyradifurone against A. craccivora with LC50 value of 1.82 mg L-1 after 48 h exposure. Treatment of parent generation (F0) with LC10 and LC25 of flupyradifurone significantly increased the longevity and fecundity of the directly exposed adults. The results of transgenerational effects showed that treatment of (F0) with LC25 induced a significant hormetic effects in progeny generation (F1). Furthermore, flupyradifurone at LC25 significantly enhanced the biological traits such as intrinsic rate of increase (r), finite rate of increase (λ) and net reproductive rate (R0) compared with the control. Similarly, both LC10 and LC25 caused a significant increase in the mean generation time T (d). Conversely ,both treatments had a significant decrease in the doubling time (DT). In conclusion, the obtained data demonstrate that exposure of (F0) to flupyradifurone at LC10 and LC25 enhanced longevity and fecundity in of the directly exposed adults of A. craccivora and induced transgenerational hormesis across the subsequent (F1) generation. These grades must be taken into consideration when using flupyradifurone against cowpea aphids.


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.


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.


2020 ◽  
Vol 25 (3) ◽  
pp. 512-524
Author(s):  
Marjan Heidarian ◽  
Yaghoub Fathipor ◽  
Amin Sedaratian-jahromi

Schizotetranychus smirnovi Wainstein is an important phytophagous pest of almond trees which causes serious damage in southwestern Iran. Scolothrips longicornis Priesner has been considered as an efficient predatory thrips that feeds on this spider mite and hence its efficiency for controlling S. smirnovi should be evaluated. In the current study, all main biological parameters of S. longicornis fed on S. smirnovi were determined under laboratory conditions. Data analysis was performed using both female age-specific and age-stage, two-sex life table theories. Duration of incubation, larval, pre-pupal, pupal and pre-adult periods of male predators were 4.73, 3.18, 1.05, 1.86 and 10.82 days, respectively. These periods in female individuals lasted 4.57, 3.92, 1.04, 1.87 and 11.00 days, respectively. Our findings showed that each female laid an average of 62.74 eggs during its ovipositional period (13.61 days). Using the age-stage, two-sex life table, the values of the net reproductive rate (R0), intrinsic rate of increase (r), finite rate of increase (λ) and mean generation time (T) were estimated to be 26.236 (eggs/individual), 0.171 (day-1), 1.186 (day-1) and 19.130 (days), respectively. Using the female age-specific life table, these parameters had different values. Our findings revealed that S. longicornis has a reliable capability to increase its population by feeding on S. smirnovi. This information can expand our knowledge for assessing biological efficiency of this predatory thrips in sustainable management of the destructive mite pest. 


2017 ◽  
Vol 22 (1) ◽  
pp. 7 ◽  
Author(s):  
Fatemeh Ganjisaffar ◽  
Thomas M. Perring

The predatory mite, Galendromus flumenis (Chant) (Acari: Phytoseiidae), has shown promising traits for biological control of Banks grass mite, the major pest of date palms in California. In the present study, reproduction and population growth parameters of G. flumenis on Banks grass mite eggs were studied at 34ºC, 50±10% RH and a photoperiod of 16: 8 (L: D) hours. 100 percent of eggs hatched and 63.5 percent of the emerged larvae survived to adulthood. The total immature developmental time was 5.7 and 5.5 days for females and males, respectively. The sex ratio of G. flumenis was 0.70 (females/ females+ males). Mated females laid on average 1.6 eggs per day and 19.9 eggs during their mean ovipositional period of 12.5 days. The net reproductive rate (R0) was 11.5 females/ female/ generation, the intrinsic rate of increase (rm) was 0.200 females/ female/ day, the finite rate of increase (λ) was 1.222 population multiplication/ day, the mean generation time (T) was 12.2 days, and the doubling time (DT) was 3.5 days. The lower rm value of G. flumenis than that of its prey (0.24–0.48) explains why Banks grass mite escapes control by G. flumenis in field. These results suggest that augmentative release of this predator would offset the lower rm of the predator, thereby contributing to the control of Banks grass mite. Combined with the benefit of early releases determined in companion studies, future field studies with G. flumenis are being planned.


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.


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.


2020 ◽  
Vol 16 (3) ◽  
pp. 119
Author(s):  
IWA .M. TRISAWA ◽  
A. RAUF ◽  
U. KARTOSUWONDO ◽  
N. MARYANA ◽  
A. NURMANSYAH

<p>ABSTRAK</p><p>Anastatus dasyni Ferr. adalah parasitoid telur kepik lada, Dasynuspiperis China. Penelitian bertujuan mengkaji kesesuaian telur kepikkedelai Riptortus linearis dan Nezara viridula sebagai inang untukpembiakan massal parasitoid A. dasyni. Imago parasitoid A. dasyni yangberasal dari lapangan dipelihara secara terpisah pada telur dari kedua jeniskepik kedelai. Pengamatan dilakukan terhadap biologi A. dasyni yangmeliputi masa perkembangan pradewasa dan berbagai parameter kehi-dupan imago betina. Selain itu, dilakukan analisis neraca hayati denganmenggabungkan data perkembangan dan sintasan pradewasa, masa hidupimago dan reproduksi, serta nisbah kelamin. Hasil penelitian menunjukkanbahwa masa perkembangan larva dan pupa A dasyni pada telur N. viridulalebih singkat serta laju peneluran lebih tinggi dibandingkan pada telur R.linearis. Imago betina A. dasyni yang keluar dari telur N. viridula hanya1,81%, sedangkan dari telur R. linearis sebanyak 70,20%. Oleh karena itu,parameter neraca hayati hanya dapat dihitung dari parasitoid yangdipelihara pada telur R. linearis. Laju pertambahan intrinsik parasitoidadalah (r) 0,1870, masa generasi (T) 27,51 hari, reproduksi bersih (Ro)84,29, laju pertambahan terbatas (λ) 1,21, dan nilai reproduksi (RVx)402,51. Proporsi persebaran usia stabil (px) adalah 17,06% telur, 50,41%larva, 26,53% pupa, dan 6,02% imago. Telur kepik kedelai R. linearisdapat digunakan untuk pembiakan massal A. dasyni.</p><p>Kata kunci : Anastatus dasyni, Dasynus piperis, Riptortus linearis,Nezara viridula, parasitoid, pembiakan massal</p><p>ABSTRACT</p><p>Suitability of soybean bug eggs for mass rearing ofAnastatus dasyni Ferr. (Hymenoptera: Eupelmidae), anegg parasitoid of pepper bug</p><p>Anastatus dasyni Ferr. is an important egg parasitoid of pepper bug,Dasynus piperis China. Research was conducted with the objectives tostudy the suitability of eggs of soybean bugs Riptortus linearis and Nezaraviridula for mass rearing of A. dasyni. Adults of A. dasyni collected fromthe field were inoculated separately on eggs of two species of soybeanbugs. Biological parameters such as immature development and adultlongevity were observed daily. Lifetable parameters were calculated on thebasis of development and survival of immature, reproduction, and sexratio. Our studies revealed that parasitoid developing on Nezara viridulaeggs had shorter larval and pupal development and higher in ovipositionrate than those on Riptortus linearis eggs. However, parasitoids emergedfrom N. viridula eggs only 1.81% were females, while from R. lineariseggs were 70.20%. Therefore, lifetable parameters can only be generatedfrom parasitoid reared on R. linearis eggs. The intrinsic rate of increase (r)mean generation time (T) 0.1870, 27.51 days, 84.29, 1.21, and 402.51respectively net reproductive rate (Ro), finite rate of increase (λ), andreproductive value (RVx). The stable stage distribution (px) were 17,06%eggs, 50,41% larvae, 26,53% pupae, and 6,02% adults. Eggs of soybeanbug R. linearis can be used for mass rearing of parasitoid A. dasyni.</p><p>Key words : Anastatus dasyni, Dasynus piperis, Riptortus linearis,Nezara viridula, parasitoid, mass rearing</p>


Insects ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 838
Author(s):  
Guang Zeng ◽  
Jun-Rui Zhi ◽  
Mao Ye ◽  
Wen Xie ◽  
Tao Zhang ◽  
...  

Exogenous calcium (Ca) has been used to induce host plant resistance in response to abiotic and biotic stresses, including from thrips attack. The aim of this study was to determine whether exogenously applied Ca affects the performance of Frankliniella occidentalis. We assessed the development time, total longevity, reproduction, and population parameters of F. occidentalis, and its preference choice on Ca-treated or untreated control kidney bean plants under laboratory conditions. The results showed that F. occidentalis fed on Ca-treated leaves had a longer developmental time but lower longevity (female and male) and fecundity than F. occidentalis fed on control leaves. Population parameters, including the intrinsic rate of increase (r), finite rate of increase (λ), and net reproductive rate (R0), were all found higher in control leaves than in Ca-treated leaves, and the mean generation time (T) was shorter. In preference choices, the number of thrips on control plants was higher than the number of thrips on Ca-treated kidney bean plants. Overall, our results indicated that exogenous Ca pretreatment on kidney bean plants affected the life history and preference choice of F. occidentalis, suggesting Ca might be used as a promising elicitor of inducible plant defense against thrips.


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