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Bragantia

On-line version ISSN 1678-4499

Abstract

COSTA, C. L.. Seazonal variation of Myzus persicae migrations at Campinas, during the years of 1967 to 1969. Bragantia [online]. 1970, vol.29, n.unico, pp. 347-359. ISSN 1678-4499.  http://dx.doi.org/10.1590/S0006-87051970000100032.

A study was made of the seazonal variations in the numbers of migrants of the aphid Myzus persicae (Sulzer) at Campinas, State of São Paulo, by sampling aerial populations from 1967 through 1969, with a suction trap and a yellow water trap. Weekly catches were recorded for both traps and summed up to give month totals. Alate viviparous parthenogenetic females of Myzus persicae were caught every week of the years of 1967 to 1969. This is an evidence that in the Campinas region (22° 50' S) there was no limiting factor to suppress parthenogenetic reproduction and inhibit flight during the period of observations. However, the trapping of males seems to indicate that an holocyclic multiplication of Myzus persicae may also exist. Where the oviparous female or other morphs of the species does also accur at Campinas, is not known. The period when most of migration took place as revealed by samples taken by both traps occurred from May to September. The yellow water trap caught more Myzus persicae than the suction trap, but curves of annual distribution of alates trapped have the same shape. The ratio between the numbers of this aphid in the two types of traps remained rather constant, throughout two years, varying from 2.3 to 6.0. This means that water trap catches were related to estimates of aerial density produced by the suction trap, a more precise apparatus for this determination, which does not exert attraction to the aphid species (20). Thus water trap may be used to the best advantage to collect Myzus persicae where an electricity supply to run the suction trap is lacking and / or when numbers of alate in the air are low. The proportion of Myzus persicae in relation to the total of species caught was also higher for the yellow water trap. In February, March, June, July and October of 1967 and June and July of 1968, 50% of aphid species caught in the water trap were Myzus persicae. It represents 35% of total caught from May to October of 1969. In the suction trap the highest proportion of this species was 20% in June, 1968. This difference is attributed to the selective attractiveness of yellow color to aphia species.

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