Showing papers on "Aphididae published in 1972"

Life tables and intrinsic rates of increase of apterous black bean aphids and pea aphids, on broad bean (homoptera: aphididae)

Abstract: Life tables were prepared from daily fecundity and survival data on 69 apterous black bean aphids, Aphis fabae Scopoli, and 47 apterous pea aphids, Acyrthosiphon pisum (Harris). Both were on broad beans in 20° ± 0.5 °C, 70–80% R.H., and 16 hr light per day. The intrinsic rates of natural increase (rm) computed from the life tables were 0.359 ♀/♀ day for the bean aphid and 0.404 ♀/♀ day for the pea aphid. Mortality was not important in determining the rates of increase because very few aphids died during their reproductive periods. Only 5 of 116 reproducing aphids died, all from inability to extrude nymphs which had died before bursting their embryonic membranes. These nymphs became covered with a discharge from the mother which cemented them in place and prevented the birth of succeeding nymphs. The resulting engorged females died in 3–4 days.An analysis of and comparison with life tables of two other aphid species in addition to those produced here showed that the differences in rm were due almost entirely to differences in fecundity. Two fecundity patterns, correlated with aphid phylogeny, were recognized.

Population dynamics and recognition of biotypes in the pea aphid (Homoptera: Aphididae).

Abstract: Five biotypes of the pea aphid, Acyrthosiphon pisum (Harris), from four hosts were recognized by their differential survival and rates of population increase on broom, white clover, alfalfa and broad beans, by body size, colour, and rates of natural increase (r m ) on broad beans. A simple method is described which can verify that the differences between r m values measured by life table analysis are not due to chance. Four of the biotypes were sympatric. It is suggested that biotypes in the pea aphid result from annual adaptations to various species of leguminous host plants and therefore other characteristics of the biotypes may vary from year to year. For this reason, only fundatrices and their immediate offspring which have not been subjected to this selection should be used as test organisms in assaying plants for resistance to pea aphids. The use of a biotype of a single year for screening plant varieties may lead to the production of varieties which are highly acceptable to other biotypes.

Studies on the ecology of Aphis craccivora Koch (Hem., Aphididae), the vector of rosette disease of groundnuts, in Uganda

Abstract: Observations on Aphis craccivora Koch at Serere, Uganda, in 1964–68 showed that dry season carry-over of aphids could occur on the common weeds Euphorbia hirta and E. prostrata; at other times aphids were seen on Gliricidia sepium, Cassia tora, Centrosema pubescens and Macroptilium atropurpureum, the last two being increasingly used as pasture legumes. In pot tests, attempts to transfer the virus through G. sepium, Cassia tora, Stylosanthes guianensis and Centrosema pubescens were unsuccessful. Volunteer groundnuts growing in open situations were an important source of virus and vector. Field studies on menazon-sprayed and unsprayed plants closely or widely spaced showed that aphid numbers increased rapidly on the groundnut crop 31–45 days from emergence but declined rapidly as the plants matured. Superficially the plants appeared to be free of aphids but large populations were often found on hypanthia, flowers and gynophores. Coccinellids, especially Cheilomenes sulphurea (Ol), were important predators. Aphid numbers were far higher on groundnuts with low plant densities, possibly because the number of favoured feeding sites is increased, but the number of plants infested was not significantly different at high and low densities. Yellow panels had little effect on aphid numbers. Spraying with menazon (294 g active ingredient/ha, 5 times) prevented breeding by incoming alates.

Trap Colors: Preference of Alate Aphids

Abstract: Studies of the biology of aphids (Aphididae) have shown that in the migrating (alate) form, many species react to color. Cartier (1965, 1966) found that the pea aphid, Acyrthosiphon pisum (Harris), and the potato aphid, Macrosiphum euphorbiae (Thomas), preferred emitted yellow and orange light to blue, green, and red light. Also, these same species showed consistently better growth when they were reared with 24 hr of light of these particular wavelengths. Other workers reported the attraction of several species of alate aphids to yellow or orange surfaces (Broadbent 1948, Moericke 1951, Kennedy and Stroyan 1959, Kring 1967), and Moericke (1955, 1969) found that some may be attracted by yellow-white surfaces with strong UV radiation. Nevertheless, actual field tests in which the color responses of aphids have been used for control have been limited. Smith et al. (1964) and Kring (1964, 1970) found that aphids may be repelled from plants surrounded by aluminum foil (strongly light-reflective).

Annotated list of aphids (homoptera: aphididae) collected in thailand, with description of a new genus and species

Abstract: A list is given of 32 species of aphids, with their host plants, from Thailand. Males and oviparae of Aphis craccivora Koch, a male of Rhopalosiphum maidis (Fitch), and an ovipara of Tinocallis kahawaluokalani (Kirkaldy) were collected. Tritrichosiphum thailandicum new genus, new species is described.

The sexuality of Myzus persicae (Sulzer), the green peach aphid, in New Brunswick (Homoptera: Aphididae)

Abstract: In New Brunswick, populations of Myzus persicae (Sulzer) on potato and weed hosts appear to be composed of anholocyclic races that have overwintered as parthenogenetic viviparous females in greenhouses, storage cellars, and other protected places. In adjacent Maine, U.S.A., holocyclic races that have overwintered as eggs on Prunus nigra Ait. are reported to be predominant in the population on potato. Holocyclic races of M. persicae are seldom encountered on P. nigra and potato in New Brunswick.

Acyrthosiphon pedicular1s, a new aphid from the district of keewatin, with a key to the canadian species (homoptera: aphididae)

Abstract: Acyrthosiphon pedicularis is described and illustrated and a key to the Canadian species of Acyrthosiphon is given.

New species of aphids (homoptera: aphididae) from thailand

Abstract: Three new species of aphids are described from collections made on Mt. Sutep in northwest Thailand: Cinara khasyae new species; Greenidea (Trichosiphum) chiengmaiensis new species; and Macrosiphum (Sitobion) yongyooti new species. The status of Greenidea (Trichosiphum) siamensis Takahashi is changed from variety to species.