Showing papers on "Aphid published in 1970"
TL;DR: It is concluded that female D .
Abstract: A suspected chemical means of habitat selection by Diaeretiella rapae, a primary parasite of aphids on crucifer plants, was investigated in the laboratory with the aid of an olfactometer. Females (and, to a lesser extent, males) were found to be attracted by odor to leaves and leaf juices of a crucifer host plant and to dilute solutions of the mustard oil allyl isothiocyanate. Given a choice of aphid colonies (Myzus persicae) on leaves of beet (Chenopodiaceae — mustard oils not present) and collard (Cruciferae — mustard oils present), female D. rapae displayed a marked preference to oviposit in aphids feeding on collard. It is concluded that female D. rapae parasites locate their hosts initially by a response to an odor emanating from the aphid host-plant, followed by visual searching. Male D. rapae were attracted by odor from female D. rapae, suggesting the existence of a sex pheromone in this species.Neither males nor females of Charips brassicae, a hyperparasite of D. rapae, were attracted to collard leaves, though females showed apparent attraction to female D. rapae. As with D. rapae, males of C. brassicae are attracted by odor to females of the same species.The host finding behavior of D. rapae is discussed in relation to that of other insect species belonging to the fauna associated with the plant family Cruciferae.
268 citations
Journal Article•
129 citations
73 citations
TL;DR: Tree dwelling aphids such as the sycamore aphid, Drepanosiphum platanoides (Schrk), feed on the phloem sap of leaves and are restricted to one host plant.
Abstract: MANY tree dwelling aphids such as the sycamore aphid, Drepanosiphum platanoides (Schrk.), feed on the phloem sap of leaves and are restricted to one host plant. If therefore the aphids affect the metabolism of the leaves of deciduous trees while they are still developing in the spring, this may subsequently affect later generations of aphids.
47 citations
TL;DR: The size of colonies of Acyrthosiphon pisum (Harris) was greatly reduced through decreased fecundity and increased mortality and dispersal rates caused by parasitization and harassment of the aphids by the aphidiid parasite Aphidius smithi Sharma & Subba Rao.
Abstract: In greenhouse and cage tests, the size of colonies of Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae) was greatly reduced through decreased fecundity and increased mortality and dispersal rates caused by parasitization and harassment of the aphids by the aphidiid parasite Aphidius smithi Sharma & Subba Rao. In the greenhouse, undisturbed colonies increased 26% in 24 hr, where the adult aphids were retained, but decreased 3% where they were removed. Where parasites were introduced, the colonies were reduced by more than 33%. The reduction in colony size in both greenhouses and cages was chiefly the result of the physiological effects of parasitization on the fecundity of the newly molted adult aphids. Harassment also caused the aphids to leave the host plant and thus increased mortality, because even the disturbance of a neighboring aphid by a parasite was enough to cause the aphids to leave the plant. Even female parasites that lacked the ability actually to parasitize the aphids were able to harass them and significantly to reduce the size of the colonies. Aphids dispersed by the parasites distributed themselves randomly, while only excess individuals moved from undisturbed colonies and these individuals went only as far as the nearest host plant.
45 citations
TL;DR: Direct comparison of the excretion rate of uniformly sized aphids feeding on seedlings and synthetic diet showed that the feeding rate on the plants was twice that on the diet.
Abstract: On the basis of honeydew excretion data for Myzus persicae (Sulzer) feeding on mustard or radish seedlings, estimates were made of the volume of sap ingested by the aphid on each day of its larval development. By difference-weighing sachets of artificial diet on which aphids were feeding, the daily uptake by aphids of such diet was determined throughout larval development. The aphids ingested a total of almost twice as much plant sap as of synthetic diet; they also grew to twice the size on the plants. Direct comparison of the excretion rate of uniformly sized aphids feeding on seedlings and synthetic diet showed that the feeding rate on the plants was twice that on the diet.
44 citations
TL;DR: Parasites were reared from the green bug, Schizaphis graminum (Rondani); the corn leaf aphid, Rhopalosiphum maidis (Fitch); and R. padi (L.) collected in 1968 and 1969 from sorghum in Oklahoma.
Abstract: Parasites were reared from the green bug, Schizaphis graminum (Rondani); the corn leaf aphid, Rhopalosiphum maidis (Fitch); and R. padi (L.) collected in 1968 and 1969 from sorghum in Oklahoma. Seven parasites representing the families Braconidae, Eulophidae, Encyrtidae, Pteromalidae, and Cynipidae were recovered. Lysiphlebus testaceipes (Cresson) was the most abundant parasite of the green bug- but was not evident in the field until August. A phelinus nigritus (Howard) and A. varipes (Foerster) were recovered in June and July from the corn leaf aphid; in August they were found parasitizing the green bug. Both parasites were recovered for the first time from field collections in Oklahoma. The most abundant secondary parasite was Aphidencyrtus aphidivorus (Mayr). Other secondary parasites reared were Pachyneuron siphonophorae (Ashmead), Charips sp., and Asaphes lucens (Provancher).
42 citations
36 citations
TL;DR: Although the transmission pattern of soybean dwarf virus is quite similar to that of other circulative aphid-borne viruses, SDV differs from any previously described virus on the basis of host range, symptoms, and vector species.
Abstract: A virus diseaase of soybeans, characterized by a rugosity of leaves and a dwarfing of plants, has been found in Hokkaido District since about 1952. The disease causes a severe damage to soybean crops. This virus, designated as soybean dwarf virus (SDV), was transmitted by the aphid, Aulacorthum solani (Kaltenbach), but not by sap inoculation nor through seeds. Of 43 species of plants in 10 families, which were inoculated by the aphids, 13 leguminous species were found to be infected with the virus. All soybean varieties tested were susceptible, though they differed in their symptom expression. The aphid was able to acquire the virus by feeding on infected soybean plants for 30-60min, and viruliferous aphids reared on source plants could transmit the virus to healthy soybean seedlings during a period of 10-30min. The longer the periods of acquisition and inoculation feedings, the higher was the transmission rate. The minimum latent period in the aphid vector was between 15 and 27hr. In serial transmission tests, the aphids retained their infectivity through molting and for periods of up to 21 days, but most of them lost infectivity in the later transfers. Although the transmission pattern of SDV is quite similar to that of other circulative aphid-borne viruses, SDV differs from any previously described virus on the basis of host range, symptoms, and vector species.
TL;DR: The bionomics of Charips victrix when associated with the primary parasites Aphidius smithi Sharma & Subba Rao and Trioxys complanatus Quilis have been examined and indicates that all developmental stages of A.smithi which occur in nonmummified aphids are attacked, but only the larval stages are suitable hosts for the development of C. victrix progeny.
Abstract: The bionomics of Charips victrix (Westwood) when associated with the primary parasites Aphidius smithi Sharma & Subba Rao and Trioxys complanatus Quilis have been examined. This investigation indicates that all developmental stages of A. smithi which occur in nonmummified aphids are attacked. However, only the larval stages are suitable hosts for the development of C. victrix progeny. Several aspects of the development of C. victrix in this host differ from those previously described.
Although the development of C. victrix described from T. complanatus is similar to that from A. smithi , the following differences were noted: (1) a few eggs were deposited in the haemocoels of several parasitized and one unparasitized aphid(s), (2) these eggs failed to develop, and (3) T. complanatus embryos were not attacked.
Behavioral responses of the spotted alfalfa aphid to C. victrix attacks tend to restrict the ability of the latter to parasitize C. complanatus . A somewhat different behavioral response is observed when the pea aphid is attacked by C. victrix . Both parasitized and unparasitized aphids are investigated by C. victrix females.
TL;DR: Because of possible long term debilitating effect by apple and woolly aphid, and the unreliability of natural control of rosy apple aphids, chemical control of aphids seems to be advisable as part of an integrated control program of apple pests.
Abstract: In 1966, 1967, and 1968 natural enemies rather than insecticides were the only means of control for 3 damaging species of aphids in a 10-acre apple orchard. The more important natural enemies of the rosy apple aphid, Dysaphis plantaginea (Passerini), the apple aphid, Aphis pomi De Geer, and the woolly apple aphid, Eriosoma lanigerum (Hausmann) were identified and evaluated. Natural enemies did not prevent damage by rosy apple aphids in 1967, or extensive leaf curl by A. pomi in 1968. Woolly apple aphids became numerous in 1967, and were reduced somewhat but not controlled satisfactorily in 1968. Because of possible long term debilitating effect by apple and woolly aphids, and the unreliability of natural control of rosy apple aphids, chemical control of aphids seems to be advisable as part of an integrated control program of apple pests. Ryania showed promise in prebloom sprays for control of rosy apple aphids. Azinphosmethyl was destructive to the major aphid enemies, but ryania and lead arsenate were harmless.
TL;DR: Male green peach aphids, Myzus persicae (Sulzer), preferred to feed on and to stay longer on peach twigs than on pear, apple, or apricot twigs, however, if extract of peach buds was applied to apple twigs (not a host plant), more males preferred the treated than the untreated twigs.
Abstract: Male green peach aphids, Myzus persicae (Sulzer), preferred to feed on and to stay longer on peach twigs than on pear, apple, or apricot twigs. However, if extract of peach buds (host plant on which the aphid overwinters) was applied to apple twigs (not a host plant), more males preferred the treated than the untreated twigs. Also, apple twigs treated with live or dead oviparae, virginoparae, or males of M. periscae or with virginoparae of the pea aphid, Acyrthosiphon pisum (Harris), (glued on) attracted more males than untreated twigs. The males always preferred twigs with live oviparae of M. persicae to those with other aphid morphs, but they showed no significant differences in preference for twigs treated with crushed oviparae, mummified aphids, or dead virginoparae of M. persicae , compared with untreated apple twigs. In the absence of females, males made numerous false mating attempts with other males.
01 Jan 1970
TL;DR: The relative resistance of the various species of Solanum under field conditions to both green peach aphid and potato aphids was found primarily in potato aphid proved highly consistent in different years despite considerable variation in pest density.
Abstract: Several sources of resistance to green peach aphid, Myzus persicae (Sulzer), and to potato aphid, Macrosiphum euphorbiae (Thomas), have been identified in the wild tuber-bearing Solanum (Tourn.) L. species. Resistance to both species indigenous to Mexico: species resistant to green peach aphid include S. bulbocastanum Dun., michoacanum (Bitt.) Rydb., brachistotrichum (Bitt.) Rydb., and stenophyllidium Bitt; species resistant to potato aphid include bulbocastanum, hjertingii Hawkes, polytrichon Rydb., and stoloniferum Schlechtd. and Bche Resistance to the 2 aphid species was generally associated. The relative resistance of the various species of Solanum under field conditions to both green peach aphid and potato aphids was found primarily in potato aphid proved highly consistent in different years despite considerable variation in pest density. Our data suggest that potato seedlings can be effectively evaluated for resistance to both green peach aphid and to potato aphid over a wide range of aphid densities.
TL;DR: Aphid infestation and incidence of plants with virus yellows in sugar-beet crops at Broom's Barn Experimental Station from 1964 to 1968 differed greatly with changes in densities of stand ranging from 8,000 to 68,000 plants per acre (0.4047 ha).
Abstract: SUMMARY
Aphid infestation and incidence of plants with virus yellows in sugar-beet crops at Broom's Barn Experimental Station from 1964 to 1968 differed greatly with changes in densities of stand ranging from 8,000 to 68,000 plants per acre (0.4047 ha), and with changes in sowing date. The numbers of Myzus persicae (Sulz.) and of Aphis fabae Scop, infesting beet during June and July, the numbers of virus-itifected plants per unit area, and the percentages of plants with yellows, usually decreased as the plant population increased but usually increased with delay in sowing from mid-March to early May.
TL;DR: The results of experiments on the effects of temperature on infectivity indicated that the aphids were more transmissible at high temperature (30°C) than low one (15 and 22°C), and there was correlation between temperature and length of latent period in the aphid vector.
Abstract: The shortest period for acquisition feeding of potato leaf roll virus by green peach aphid (Myzus persicae Sulzer) from infected potato or Datura stramonium L. plants was 5 to 10 minutes. Viruliferous aphids transmitted the virus to healthy Physalis floridana Ridb. plants by inoculation feeding of at least 5 minutes.The transmission threshold period of potato leaf roll virus in aphids was 16-24 hours in room temperature, but latent period after acquisition feeding of 1, 4 and 8 hours was found to be 23-24, 12-16 and 8-16 hours, respectively, and also it differed with infection source plants.The results of experiments on the effects of temperature on infectivity indicated that the aphids were more transmissible at high temperature (30°C) than low one (15 and 22°C).The shortest latent period was found to be 72 hours at 15°C, 16 hours at 20°C and 8 hours at 25-30°C, respectively. It indicated that there was correlation between temperature and length of latent period in the aphid vector.
TL;DR: Several aspects of host selection by Charips victrix (Westwood) were investigated, finding that females could discriminate between suitable hosts (A. smithi) and unsuitable hosts (Aphelinus “L”) both through the pea aphid.
Abstract: Several aspects of host selection by Charips victrix (Westwood) were investigated. The following summarizes the experimental findings: (1) unparasitized aphids were probed but eggs were not deposited in them; (2) parasitized aphids were found readily among unparasitized aphids; (3) unparasitized pea aphids, Acyrthosiphon pisum (Harris), were probed more frequently by females than unparasitized spotted alfalfa aphids, Therioaphis trifolii (Monell); (4) more eggs were deposited in larvae of Aphidius smithi Sharma & Subba Rao through the pea aphid than in larvae of Trioxys complanatus Quilis through the spotted alfalfa aphid; and (5) C. victrix females could discriminate between suitable hosts (A. smithi) and unsuitable hosts (Aphelinus “L”) both through the pea aphid.
TL;DR: Populations of the balsam woolly aphid, Adelges piceae (Ratzeburg), on Fraser fir and factors affecting them were observed for a 2-year period and Crawlers, neosistentes, and adults of the aphid are well adapted to survive weather conditions occurring when aphids in these stages are most prevalent.
Abstract: Populations of the balsam woolly aphid, Adelges piceae (Ratzeburg), on Fraser fir and factors affecting them were observed for a 2-year period. The host tree was the most important factor affecting the aphid after peak population was reached. The number of aphids settling on each tree greatly exceeded the carrying capacity of the tree; survival of aphids was correlated with condition of the tree. Early infestation of a tree is probably related to aphid density—the aphid modifies the bark and the result is increased fertility and survival of aphids per unit area of bark.
Predators had little effect on the aphid population; primarily they ate eggs and showed a numerical response to egg density. However, egg losses attributed to predators were small when compared to total egg mortality and to egg survival. Survival of eggs was either not related to expected predation or increased as predation increased.
Weather factors were considered primarily responsible for large losses of eggs, but were of little consequence in the dynamics of the aphid. Crawlers, neosistentes, and adults of the aphid are well adapted to survive weather conditions occurring when aphids in these stages are most prevalent.
TL;DR: The results indicate that the aphid utilizes sugars in a descending order of glucose, pentose sugars, fructose, and dextrins, and amides and carbamyl compounds occur in significant concentrations high enough to indicate that its excretory mechanism could be severely taxed to provide for their elimination.
TL;DR: The results of this study indicate that the diet of plant-reared apterous Myzus persicae is relatively morph-inactive and presumptive alatiform larvae are produced on diet as a result of interactions between their mothers.
TL;DR: Microscopical examination reveals that resistant populations of the peach–potato aphid, Myzus persicae (Sulzer), have better developed lateral abdominal tubercles on segments 2–4 than susceptible populations.
Abstract: POPULATIONS of the peach–potato aphid, Myzus persicae (Sulzer), that have survived exposure to organophosphorus insecticides are sometimes received for identification in the British Museum (Natural History). Microscopical examination reveals that resistant populations have better developed lateral abdominal tubercles on segments 2–4 than susceptible populations. The resistance of Myzus persicae to demeton-methyl is not stable, a twenty-five-fold resistance being acquired during seven clonal generations exposed to it and lost during thirty generations not exposed1. Experiments being done at Rothamsted Experimental Station (C. J. B., in preparation) made it possible to study the morphology of aphids from susceptible and resistant aphid populations and to compare them with each other and with susceptible members of a previously resistant population.
TL;DR: A sta tistically significant correlation was found between the attractiveness of Cruciferae to winged aphids and the rate of reproduction of the aphids.
Abstract: Hyadaphis pseudobrassicae (Davis) was tested as a pest of 19 species and botanical varieties of cruciferous oilseeds Only PI 171538, an introduction of Brassica napus L., was resistant of the 390 plant introductions and varieties of Brassica spp. screened. Also, no resistance was found in Any introductions of Eruca sativa Mill., Camelina sativa (L.) Crantz, Raphanus raphanistrum L., R. sativus L. Thalaspi arvense L., or Lepidiurn sativum L. However, Alyssum dasycarpum Steph. ex Willd., was highly resistant and may not be a host. In general, the winged forms of the aphid were most attracted by crucifers on which the rate of reproduction was greatest, but C. sativa was an exception: this species was unattractive to winged aphids, though it was highly susceptible to aphid feeding. A sta tistically significant correlation (r = 0.675 with 47 df) was found between the attractiveness of Cruciferae to winged aphids and the rate of reproduction of the aphids.
TL;DR: Both aphid-resistant and Aphid-susceptible alfalfa varieties were more attractive to the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), in cages containing spotted al falfa aphids, than in cages lacking aphids.
Abstract: Both aphid-resistant and aphid-susceptible alfalfa varieties, Medicago sativa L., were more attractive to the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), in cages containing spotted alfalfa aphids, Therioaphis maculata (Buckton), than in cages lacking aphids. However, plant bug increase on the aphid-resistant variety 'Kanza' was only 17.6%, compared with 123.2% for the aphid-susceptible variety 'Alfa.' In the absence of aphids, attractiveness of the 2 varieties was similar. Rate of tarnished plant bug mortality was markedly lower in cages containing aphids than it was in control cages.
Tarnished plant bugs were observed feeding on pea aphids ( Acyrthosiphon pisum (Harris), and spotted alfalfa aphids. When caged on an aphid-susceptible alfalfaclone, adult plant bugs apparently destroyed an average of 2.4 spotted alfalfa aphid and 2.1 pea aphid nymphs per day.
Alfalfa sprayed with a 10% sucrose solution attracted significantly more (72%) bugs than did unsprayed alfalfa. Bug increases from spraying were 33 and .143% for 'KSl0' and Alfa, respectively.