scholarly journals Resistance performance of four principal apple cultivars to woolly apple aphid, Eriosoma lanigerum (Hemiptera: Pemphigidae), by simulated seasonal temperature in northern China

2021 ◽  
Vol 15 (1) ◽  
pp. 59-69
Author(s):  
Xiu-Mei Tan ◽  
Zhuo-Shi Yang ◽  
Hao Zhou ◽  
Qin-Min Yang ◽  
Hong-Xu Zhou
Keyword(s):  
Growth Rate ◽  
Durable Resistance ◽  
Resistance Mechanism ◽  
Northern China ◽  
Reproductive Rate ◽  
Seasonal Temperature ◽  
Eriosoma Lanigerum ◽  
Net Reproductive Rate ◽  
Woolly Apple Aphid ◽  
Apple Cultivars

AbstractWoolly apple aphid (WAA), Eriosoma lanigerum (Hausmann) (Hemiptera: Pemphigidae), is a worldwide quarantine pest of apples. Understanding the resistance mechanism of various cultivars to WAA is important for the selection for durable resistance. Few studies have examined the resistance of different apple cultivars to WAA in China; among common varieties produced in China, Red Fuji is highly sensitive to WAA. In this study, the resistance to WAA of Red Fuji and three other common cultivars—Starkrimson, Jonagold, and Ralls Genet—was assessed based on the developmental and reproductive biological characteristics of aphids, assessed under four fixed temperatures: 20, 25, 30, and 35 ℃. We found the optimal temperature for WAA growth and reproduction to be 20–25 ℃, at which temperature, aphids on Red Fuji showed the highest rate of reproduction, the highest number of colonies, and the greatest area covered by aphid colonies among the four cultivars. These attributes of WAA were significantly higher at 20–25 ℃ than at 30 ℃. On Red Fuji, the most favorable variety, WAA showed its highest net reproductive rate (127.3 ± 13.3), intrinsic growth rate (0.30 ± 0.01), highest growth rate of the colony area (1.35 ± 0.02), and the lowest average generation time (16.1 ± 0.8 day) at 25 ℃. The aphids inoculated onto the four tested cultivars all died within 1 week at 35 ℃. Overall, Red Fuji was highly susceptible, while Starkrimson, Jonagold, and Ralls Genet were partially resistant.

Efficiency of growth and wool production of young Merino ewes from a flock selected for fertility

1976 ◽  
Vol 16 (80) ◽  
pp. 315 ◽  
Author(s):  
KD Atkins ◽  
GE Robards
Keyword(s):  
Growth Rate ◽  
Organic Matter ◽  
Reproductive Rate ◽  
Feed Conversion ◽  
Or Efficiency ◽  
Net Reproductive Rate ◽  
Wool Production ◽  
Significant Difference ◽  
Digestible Organic Matter ◽  
Conversion Efficiencies

A handfeeding experiment was conducted with weaner ewe lambs from two Merino flocks. One flock had been selected for high net reproductive rate, growth rate and wool production (fertility flock) ; the other flock was a randomly selected control flock (random flock). Single and twin born lambs from each flock were used in the experiment. Lambs were randomized into four treatment groups and offered the diet either ad libitum or at one of three levels estimated to restrict growth rate to 50, 100 and 150 g day-1. At each level of feeding, fertility flock lambs grew faster and were more efficient in converting feed to liveweight gain. Over the whole experiment the feed conversion efficiencies in g gain per kg digestible organic matter intake per day were 218 and 185 (P < 0.05) for the fertility and random flocks respectively. There were no significant differences in growth rate or efficiency of conversion of feed to liveweight gain between single-born and twin-born lambs. Random flock lambs had a significantly higher wool growth rate and were more efficient converters of feed to wool than fertility flock lambs. Gross efficiencies were 10.8 and 9.1 g clean wool per kg digestible organic matter intake per day (P < 0.05) for random and fertility flock lambs respectively. Single-born lambs grew significantly more wool than twin-born lambs but there was no significant difference between birth types in the efficiency of conversion of feed to wool.

Comparative Analysis of Stylet Penetration Behaviors of Eriosoma lanigerum (Hemiptera: Aphididae) on Main Apple Cultivars in China

2020 ◽  
Vol 113 (4) ◽  
pp. 1761-1767 ◽  
Author(s):  
Zhou Hao ◽  
Du Lingjun ◽  
Wan Fang-Hao ◽  
Zhou Hongxu
Keyword(s):  
Total Duration ◽  
Fourth Instar ◽  
Electrical Penetration Graph ◽  
Eriosoma Lanigerum ◽  
Woolly Apple Aphid ◽  
Sieve Cells ◽  
Behavioral Mechanism ◽  
Epg Technique ◽  
Apple Cultivars ◽  
Phloem Feeding

Abstract The preference and behavioral mechanism of the feeding behavior of the woolly apple aphid, Eriosoma lanigerum (Hausmann), on Chinese apple cultivars was investigated using the electrical penetration graph (EPG) technique. Feeding of adult aphids was assessed for the four main cultivars of apple in China (Red Fuji, Ralls Genet, Starkrimson, and Jonagold) over an 8-h monitoring period, what that of fourth-instar nymphs was assessed for 8 h on Jonagold only. EPG waveforms representing the details of probing behaviors, parameters were measured for analysis. We found that at the nonphloem phase, the total duration of the nonpenetration (np) waveform and the total duration of the stylet pathway phase (the ‘C wave’) on Ralls Genet and Starkrimson were significantly longer than on Red Fuji. In addition, the phloem-feeding phase, the total duration of ‘release of saliva into the phloem’, (the E1 waveform) was significantly longer on Ralls Genet and Jonagold than on Red Fuji. The total duration of the ‘ingestion from sieve cells’ phase (the E2 waveform) on Red Fuji, meanwhile, was significantly longer than on Ralls Genet or Starkrimson. At the same time, when combined with EPG parameters, Red Fuji was found to have no obvious resistance to woolly apple aphid and to be a susceptible cultivar. This experiment also recorded the feeding waveform of fourth-instar aphid nymphs. Based on the phloem and nonphloem parameters recorded in this study, it was inferred that adult aphids are more likely than nymphs to feed on apple trees.

Alterations in Population Growth Rate of Caenorhabditis elegans Exposed to Dichlorvos

2014 ◽  
Vol 1073-1076 ◽  
pp. 101-105
Author(s):  
Chun Hua Wang ◽  
Chao Pin Li
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Life Table ◽  
Population Growth Rate ◽  
Culture Medium ◽  
Reproductive Rate ◽  
Net Reproductive Rate ◽  
C Elegans ◽  
Hanging Drop Method ◽  
Fluid Culture

Dichlorvos is an environmental hormone insecticide, and several studies have demonstrated its toxic effects on C. elegans. However, little is known about its effect on the population growth rate of nematode cohort. After exposing worms to dichlorvos (1, 10 and 50 μmol/L) for 4h, a life table experiment was conducted by a hanging-drop method with a semi-fluid culture medium. Results showed that the survival rate and fecundity of worms decreased significantly, and concentration-dependent inhibitions were also observed in net reproductive rate, total fertility rate, average lifespan and population growth rate, so these parameters were approved to be sensitive to dichlorvos, and could be used as monitors of dichlorvos pollutant. The life table experiment measured several life-cyle traits simultaneously, and integrated them into population growth rate, which reflects a population’s response to a specific pollutant. The experimental results proved that life table experiment was important for assessment of pollutants.

Effects of the biochemical composition of three microalgae on the life history of the rotifer Brachionus plicatilis (Alvarado strain): an assessment

2018 ◽  
Vol 54 ◽  
pp. 20 ◽  
Author(s):  
Ignacio Alejandro Pérez-Legaspi ◽  
Brenda Marina Guzmán-Fermán ◽  
Jesús David Moha-León ◽  
Luis Alfredo Ortega-Clemente ◽  
Verónica Valadez-Rocha
Keyword(s):  
Growth Rate ◽  
Life Table ◽  
Biochemical Composition ◽  
Production Systems ◽  
Brachionus Plicatilis ◽  
Dry Weight ◽  
Reproductive Rate ◽  
Toxicity Tests ◽  
Net Reproductive Rate ◽  
Table Analysis

The biochemical composition of microalgae used as food is essential for aquatic species in commercial production systems, such as rotifers and microcrustaceans. Life table bioassays with the rotifer Brachionus sp. “Alvarado” strain were performed using three microalgae (Nannochloropsis oculata, Dunaliella salina and Isochrysis sp.) as food. Microalgae growth rate, dry weight and biochemical composition (protein, lipid, carbohydrate) and pigments (chlorophyll and carotenoid) were determined. The microalgae showed significant differences in their biochemical composition. N. oculata showed the highest growth rate, while D. salina showed the slowest growth rate, but instead, it displayed a higher content of proteins, lipids, carbohydrates, chlorophyll, and carotenoids per cell. Rotifer life table analysis showed no significant differences among any of the microalgae as food bioassays. However, Isochrysis sp. had a higher effect on the net reproductive rate of the rotifer Brachionus sp. “Alvarado” followed by D. salina, while N. oculata showed a higher effect on life expectancy and generation time. In conclusion, the three microalgae are found to be useful to support rotifer cultures; however, both, D. salina and Isochrysis sp., might improve the rotifer culture due to better growth and reproduction in short time. This information is useful to implement the culture of this tropical strain of Brachionus plicatilis complex in order to obtain high population densities, making rotifers available for several applications such as the establishment of larviculture in hatcheries, bioassays for ecological studies or to assess its sensitivity through toxicity tests.

scholarly journals Comparative demography of the exotic Harmonia axyridis with other aphidophagous coccinellids reared on artificial diet

2014 ◽  
Vol 49 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Julianne Milléo ◽  
Francisco Sales Fernandes ◽  
Wesley Augusto Conde Godoy
Keyword(s):  
Life Table ◽  
Harmonia Axyridis ◽  
Reproductive Rate ◽  
The Other ◽  
Adult Longevity ◽  
Net Reproductive Rate ◽  
Anagasta Kuehniella ◽  
Survival Percentage ◽  
Comparative Demography ◽  
Biological Aspects

The objective of this work was to compare biological aspects and life table parameters of the coccinellids Harmonia axyridis, Cycloneda sanguineaand Hippodamia convergens. Insects were fed eggs of Anagasta kuehniella, and reared at 24.5±1ºC, 70±10% relative humidity, with a 12 hour photophase. Hippodamia convergenstook about 1.6 day to complete development, longer than H. axyridis, and 2.4 day longer than C. sanguinea.At immature stages, H. axyridisexhibited the highest survival percentage (49.2%), in comparison to the other coccinellids. For mean adult longevity, H. convergenswas deficient, in comparison with the other species. Mean period of pre oviposition was the longest in C. sanguinea; the longest oviposition time occurred for H. axyridis; and the post oviposition period was similar between the coccinellids. Considering the reproductive parameters, H. axyridisshowed the best performance in all aspects. For life table, the values of H. convergenswere higher than, although close, to those of H. axyridis. Nevertheless, the high net reproductive rate of H. axyridis showed this species potential to increase population size. The biological characteristics of the exotic H. axyridis favors its invasion and establishment in Brazil, corroborating results noticed in other countries.

scholarly journals Effects of Delayed Mating on the Reproductive Performance of Henosepilachna vigintioctopunctata (F.) (Coleoptera: Coccinellidae)

Insects ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 629
Author(s):  
Ya-Ling Wang ◽  
Qi-Nian Jin ◽  
Xiang-Ping Wang
Keyword(s):  
Life Table ◽  
Mating Success ◽  
Doubling Time ◽  
Reproductive Rate ◽  
Oviposition Period ◽  
Population Doubling ◽  
Life Table Parameters ◽  
Effective Measure ◽  
Net Reproductive Rate ◽  
Henosepilachna Vigintioctopunctata

Henosepilachna vigintioctopunctata (F.) is a serious pest of numerous solanaceous crops in many Asian countries. The purpose of this study was to clarify the effects of delayed mating on mating success, fecundity, fertility, pre-oviposition period, oviposition period, adult longevity, and population life table parameters (including net reproductive rate, intrinsic and finite rates of increase, doubling time, and mean generation time) of H. vigintioctopunctata. Beginning three days after emergence for both sexes, mating was delayed an additional 0, 2, 4, 6, or 8 days. We compared the data when mating was delayed for males only with the data when mating was similarly delayed for females only. Reproductive and life table parameters were calculated from the two data sets and compared. The results showed that the preoviposition and oviposition period of adults was significantly reduced by delayed mating, while the preoviposition period was not significantly different in adults mated at older ages. The mating success rate, fecundity, and proportion of hatching eggs decreased with increasing mating age. Longevity was not affected by the age at mating. Mating delay also affected the life table parameters of H. vigintioctopunctata, with a similar trend observed in the net reproductive rate and intrinsic and finite rates of increase, all of which decreased gradually as the number of delay days increased. The population doubling time increased with increases in mating age. The results also showed that delayed mating was an effective measure to consider in controlling H. vigintioctopunctata. It is hoped that our data will provide a scientific basis and contribute technical guidance for forecasting and integrated management of this pest.

Plant Resistance in Some Modern Soybean Varieties May Favor Population Growth and Modify the Stylet Penetration of Bemisia tabaci (Hemiptera: Aleyrodidae)

2021 ◽  
Author(s):  
Mauricélia F Almeida ◽  
Clébson S Tavares ◽  
Euires O Araújo ◽  
Marcelo C Picanço ◽  
Eugênio E Oliveira ◽  
...  
Keyword(s):  
Population Growth ◽  
Bemisia Tabaci ◽  
Intrinsic Rate ◽  
Reproductive Rate ◽  
Genetically Engineered ◽  
Population Increase ◽  
Net Reproductive Rate ◽  
Bt Toxin ◽  
Demographic Performance

Abstract Complaints of severe damage by whiteflies in soybean fields containing genetically engineered (GE) varieties led us to investigate the role of transgenic soybean varieties expressing resistance to some insects (Cry1Ac Bt toxin) and to herbicide (glyphosate) on the population growth and feeding behavior of Bemisia tabaci (Gennadius) MEAM1 (Hemiptera: Aleyrodidae). In the laboratory, the whiteflies reared on the GE Bt soybeans had a net reproductive rate (R0) 100% higher and intrinsic rate of population increase (rm) 15% higher than those reared on non-GE soybeans. The increased demographic performance was associated with a higher lifetime fecundity. In electrical penetration graphs, the whiteflies reared on the GE soybeans had fewer probes and spent 50% less time before reaching the phloem phase from the beginning of the first successful probe, indicating a higher risk of transmission of whitefly-borne viruses. Data from Neotropical fields showed a higher population density of B. tabaci on two soybean varieties expressing glyphosate resistance and Cry1Ac Bt toxin. These results indicate that some GE soybean varieties expressing insect and herbicide resistances can be more susceptible to whiteflies than non-GE ones or those only expressing herbicide resistance. Most likely, these differences are related to varietal features that increase host-plant susceptibility to whiteflies. Appropriate pest management may be needed to deal with whiteflies in soybean fields, especially in warm regions, and breeders may want to consider the issue when developing new soybean varieties.

scholarly journals Biological performance of the predatory mite Neoseiulus idaeus (Phytoseiidae): a candidate for the control of tetranychid mites in Brazilian soybean crops

2016 ◽  
Vol 77 (2) ◽  
pp. 361-366 ◽  
Author(s):  
M. B. Reichert ◽  
M. Toldi ◽  
P. A. Rode ◽  
J. J. Ferla ◽  
N. J. Ferla
Keyword(s):  
Adult Development ◽  
Predatory Mite ◽  
Reproductive Rate ◽  
Agricultural Crop ◽  
Net Reproductive Rate ◽  
Glycine Max L ◽  
The Mean ◽  
Neoseiulus Idaeus ◽  
Biological Performance ◽  
Northwest Region

Abstract The soybean (Glycine max (L.): Fabaceae) is considered the most important agricultural crop in Brazil. Phytophagous tetranychid mites as Mononychellus planki McGregor, Tetranychus ludeni Zacher and T. urticae Koch have been considered pest in soybean crops. Neoseiulus idaeus Denmark & Muma (Phytoseiidae) is a predatory mite of T. ludeni and T. urticae. The aim of the present study was to evaluate the biological performance of N. idaeus when fed on T. urticae, T. ludeni and M. planki, coming from the Northwest region of Rio Grande do Sul state, Brazil. The study was conducted in the laboratory with individual predators supplied with different preys. The mean duration (days) of N. idaeus egg-adult development was similar independently of supplied prey (T. ludeni - 5.29±0.03; M. planki - 5.34±0.05 and T. urticae - 5.23±0.03 days). Female viability was 90% when fed on M. planki and 100% when fed on T. ludeni and T. urticae. Mean fecundity of N. idaeus was lower when fed on M. planki (4.6±1.58 eggs/female) and higher when fed on T. ludeni (21.8±3.22) and T. urticae (26.2±2.41). The mean generation time (T) was lower when N. idaeus fed on M. planki than when fed on T. ludeni and T. urticae. The net reproductive rate (Ro) was 4.42±0.49 on M. planki, 17.77±0.55 on T. ludeni and 20.59±0.48 on T. urticae. The innate capacity for increase (rm) was lower when N. idaeus was fed on M. planki (0.09) and higher when such predator was fed on T. ludeni (0.20) and T. urticae (0.22 females/females/day). These results demonstrated that N. idaeus is able to reach the complete development feeding on all the three tetranychid species. Mononychellus planki demonstrated to provide a sub-optimal diet if compared to T. ludeni and T. urticae.

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