Biology and fertility life table of grapevine aphid on grape cultivars

The objective of this work was to evaluate the biology and fertility life table of the grapevine aphid [Aphis illinoisensis (Hemiptera: Aphididae)] on seedlings of the grape cultivars of Vitis labrusca, Bordo, and of V. vinifera, Cabernet Franc, Italy, and Moscato Bianco. The experiment was carried out in 50 small-cage confinement, with one insect in each small-cage per treatment, fixed in grapevine seedlings kept in a phytotron-type growth chamber (at 25 +/- 1 degrees C, 75 +/- 10% relative humidity, and 14-hour photophase). Duration and viability of nymphal stages, fecundity, and longevity of the species reproductive period were daily evaluated. Grapevine aphid completed its life cycle in grape seedlings of the mentioned cultivars, with nymphal stage duration of 7.9 +/- 0.3, 6.8 +/- 0.2, 6.2 +/- 0.2 and 6.7 +/- 0.2 days, and viability of 58, 82, 98, and 80%, for 'Bordo', 'Cabernet Franc', 'Italia', and 'Moscato Bianco', respectively. 'Cabernet Franc' and 'Moscato Bianco' were more favorable to the grapevine aphid development, based on the fertility life table, with 51.3 and 55.6 offspring per female, per generation, respectively. 'Bordo' was the less suitable for this aphid development, with 12.55 offspring per female, per generation, which indicates a antibiosis-type resistance or insect nonpreference for this cultivar.