Biological aspects of Aphis gossypii Glover, 1877 (Hemiptera: Aphididae) on three cotton cultivars and on three weeds species

摘要

The objective of this work was to study the biological aspects of A. gossypii on three cotton cultivars and on three weed species. The experiment was carried out in the Laboratory of Biological Control, under controlled conditions of temperature (25 ± 1?oC), relative humidity (70 ± 10%) and photophase (12h). Treatments were: three cotton cultivars (CNPA ITA 90, Coodetec 402 and Deltaopal) and three weed species (Sida santaremnensis, Sidastrum micranthum and Commelina benghalensis). The experimental units (25 replicates) consisted of Petri dishes containing agar-water (1%) solidified. Aphids were kept individually on leaf discs (3cm diameter) of each respective treatments. The lowest number of days for nymphal phase was obtained on CNPA ITA 90 (4.39 ± 0.74), Deltaopal (4.45 ± 0.75), Coodetec 402 (4.47 ± 0.75) and C. benghalensis (4.75 ± 0.80). Reproductive period and adult longevity varied from 8.21 ± 0.85 to 15.52 ± 0.93 and from 11.09 ± 0.97 to 24.33 ± 1.59 days, respectively on S. santaremnensis and Deltaopal. Cotton cultivars are more favorable to A. gossypii than weeds and, in the absence of cotton plants, S. santaremnensis, S. micranthum and C. benghalensis are potential hosts.