SINOPSEPara estudar as variações sazonais do número de migrantes de Myzus persicae (Sulz.) em Campinas, foram utilizadas armadilhas de dois tipos, para a sua coleta: a de sucção e a de água.Fêmeas vivíparas, partenogenéticas, aladas, da espécie, foram coletadas em todas as semanas durante os anos de 1967, 1968 e 1969. A presença de alguns raros machos foi também registrada.A armadilha de água coletou sempre maior número de indivíduos do que a de sucção, durante todo o período de observações. Entretanto, as curvas que representam as variações semanais e mensais do número de migrantes da espécie, construídas com as amostras obtidas por ambos os tipos de armadilhas, têm a mesma forma. As maiores migrações se deram nos meses de maio a setembro.A proporção de exemplares de M. persicae em relação ao total das espécies coletadas foi sempre maior na armadilha de água do que na de sucção. -INTRODUÇÃOO papel preponderante das formas aladas dos afídios sobre as ápteras na transmissão de vírus de plantas para as culturas e geralmente aceito pelos autores desde há muito. A existência O autor expressa seus agradecimentos ao Dr. A. S. Costa, Chefe da Seção de Virologia, pelas sugestões oferecidas na discussão e interpretação dos resultados dêste trabalho.

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Yellow water traps are often used for sampling populations of flying aphids. This note suggests that the size and probably the shape of traps should be standardised, because trapping efficiency (nos. caught/unit area), and the relative attractiveness of traps to different species, depends on trap size. Aphidologists using water traps to compare mixed populations of flying aphids, should therefore compare catches from different traps with caution. Traps of three sizes were made up from individual trays, each 29 × 21.5 × 5 cm, and painted Hansa yellow inside; 1 tray alone, 4 arranged in a 2 × 2 rectangle, and 9 in a 3 × 3 rectangle, gave trapping surfaces of approx. 625, 2500 and 5700 cm2 respectively. The traps were half‐filled with water plus a drop of detergent, placed on bare land and daily catches collected on 19 days in June and July 1966.

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S U M M A R YAcyrthoszphon pisum was a more efficient vector than Myxus persicae of bean leaf roll virus (BLRV), but the two species transmitted pea enation mosaic virus (PEMV) equally well and much more often than Megoura viciae. M . wiciae did not transmit BLRV, and Aphis fabae did not transmit BLRV or PEMV.BLRV and PEMV were transmitted more often by nymphs of A . pisum than by adult apterae or alatae that fed on infected plants only as adults, but both viruses were readily transmitted by adults that had developed on infected plants. The shortest time in which nymphs acquired BLRV was 2 h, and so(% transmitted after an acquisition period of 4 days. Some nymphs acquired PEMV in 30 min and 50% in 8 h. The shortest time for inoculation of BLRV by adults was 15 min, but some transmitted PEMV in probes lasting less than I min. The median latent periods of BLRV and PEMV in aphids fed for I Z h on infected plants were, respectively, 105 and 44 h.Clones of A . pisum differed in their ability to transmit BLRV and PEMV, and efficiency in transmitting the two viruses seemed to be unrelated. Some aphids that fed successively on plants infected with each virus transmitted both viruses, and infectivity with one virus did not seem to affect transmission of the other.