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Aphid

About: Aphid is a research topic. Over the lifetime, 11380 publications have been published within this topic receiving 229721 citations. The topic is also known as: Aphidoidea & plant lice.


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Journal ArticleDOI
TL;DR: The results suggest that there is little or no difference between intra and interspecific interactions among larvae of these ladybeetles when two similarly sized individuals co-occur on a host plant, and the species diversityper se of assemblages of lady Beetle larvae may have little influence over the short term on the reduction of aphid populations by lady beetle predation.
Abstract: The nature and relative strengths of intra versus interspecific interactions among foraging ladybeetle larvae were studied experimentally by measuring short-term growth rates of predators and reductions in population sizes of prey in laboratory microcosms. In these microcosms, ladybeetle larvae foraged singly or as conspecific or heterospecific pairs, for pea aphids on bean plants over a two-day period. Similarly sized third instar larvae ofHippodamia convergens andH. tredecimpunctata, H. convergens andH. sinuata, andH. convergens andCoccinella septempunctata, were tested in experiments designed to ensure that paired larvae experienced moderate competition. Interspecific competition in these experiments did not differ significantly from intraspecific competition, in that an individual's weight gain did not depend on whether its competitor was heterospecific or conspecific. Furthermore, aphid populations were reduced equally by heterospecific and conspecific pairs. These results suggest that there is little or no difference between intra and interspecific interactions among larvae of these ladybeetles when two similarly sized individuals co-occur on a host plant. Thus, the species diversityper se of assemblages of ladybeetle larvae may have little influence over the short term on the reduction of aphid populations by ladybeetle predation.

109 citations

Journal ArticleDOI
TL;DR: Recent cultural practices in California cotton include higher rates of nitrogen fertilization, which increases nitrogen content of plants, which is an important factor contributing to the increased severity of the cotton aphid as a pest of California cotton during the midseason.
Abstract: Field experiments were conducted from 1996 to 1998 to assess the effects of nitrogen fertilization rates and planting dates on the population dynamics of the cotton aphid, Aphis gossypii Glover, during the midgrowing season of California cotton. Cotton aphids reached higher densities in high nitrogen fertilized plants (227 kg N/ha, rate currently used by cotton growers) than in low nitrogen fertilized plants (57 kg N/ha). In addition, late-planted cotton (May–June), which had more nitrogen content, also harbored higher aphid populations than early plantings (April). Overall, aphid abundance was positively correlated with plant nitrogen content. In a moderate aphid pressure year (1996), planting the cotton early (April) was effective in keeping the aphid population below the midseason economic threshold. However, in a high aphid pressure year (1997), it was necessary to drastically reduce the nitrogen fertilization to 57 kg N/ha to maintain the aphid density under this threshold. Recent cultural practices in California cotton include higher rates of nitrogen fertilization, which increases nitrogen content of plants. The current data suggest that this practice (i.e., high fertilization) is an important factor contributing to the increased severity of the cotton aphid as a pest of California cotton during the midseason.

109 citations

Journal ArticleDOI
TL;DR: The capability of amino acid conversion of the aphid was investigated and the following amino acids were found labelled exclusively in the symbiotic aphids: arginine, histidine, isoleucine and/or leucine, lysine, phenylalanine, threonine and valine, suggesting that-these so-called essential amino acid were produced with the aid of symbionts.

109 citations

Journal ArticleDOI
TL;DR: How wind and rain affect reproductive success and parasitization patterns of the aphid parasitoid Aphidius rosae in rose bushes is investigated and it is shown that wind andRain change the distribution of parasitism among host colonies.
Abstract: 1. Weather conditions are known to influence insect behaviour and population dynamics. We investigated how wind and rain affect reproductive success and parasitization patterns of the aphid parasitoid Aphidius rosae in rose bushes. 2. A model was developed to simulate the life history of females foraging in the field under different environmental conditions. The model was parameterized using field and laboratory data on foraging behaviour of A. rosae. Field data on the daily occurrence of wind and rain were used for the simulation of different weather conditions. 3. When 1 day in the life of a female was modelled, both wind and rain reduced the number of aphid colonies and rose bushes visited. During rain, the parasitoid ceased all foraging activities, resulting in a negative correlation between the number of eggs being laid in visited aphid colonies, and the duration of rain during a day. During wind, the parasitoid continued to forage at a reduced rate, which led to increasing rates of parasitism in encountered aphid colonies during long wind intervals. 4. In a field study, we linked patterns of parasitism in aphid colonies to the weather conditions at the time when the eggs were laid by the parasitoids. The results confirmed the predictions of the model and showed that wind and rain change the distribution of parasitism among host colonies. 5. When the lifetime reproductive success of foraging females was simulated, both wind and rain affected parasitoid reproductive success. Even if weather conditions were benign, the reproductive success of females was greatly reduced compared to the maximum achievable oviposition numbers in the absence of any bad weather periods. Weather conditions had a less pronounced effect on parasitoid life history if travel mortalities between patches were taken into consideration. 6. Both bad weather conditions and travel mortality led to a strong skew in the frequency distribution of female reproductive success. A small proportion of females was able to realize oviposition numbers close to the maximum lifetime fecundity, as measured in the laboratory.

109 citations

Journal ArticleDOI
TL;DR: The observations strongly suggest that aphid population growth was stopped by aphid-specific predators, hymenopterous parasitoids and fungal pathogens.
Abstract: SUMMARY Winter wheat fields on two farms in West Sussex were sampled in 1980 and 1981 for cereal aphids and their natural enemies. The grain aphid, Sitobion avenae was present in all 19 fields examined, but in no case did the populations increase to densities liable to cause economic damage. The observations strongly suggest that aphid population growth was stopped by aphid-specific predators, hymenopterous parasitoids and fungal pathogens. In two fields in 1980, S. avenae population densities approximately equalled five aphids per ear at flowering, the threshold at which insecticide application is recommended in the UK, but numbers were then reduced by natural enemies, mainly aphid-specific predators. In three fields in 1981, S. avenae would probably have exceeded the spray threshold had natural enemies not intervened in late May.

109 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023387
20221,082
2021337
2020393
2019373
2018382