Sunflower plants, cv Anhandy, freely visited by insects (control) were compared to plants protected from insects. Two flower isolation methods were used: covering the plants with net cages (width 3m, lenght 4m, height 2m) and bagging the flowers with gauze. The number, the weight and the percentage of seed setting were significantly higher (P<0.05) in the visited plants (579.28; 41.17g and 82.37%; 456.97; 23.44g 79.70%, in two trials) than in plants protected by cages (81.53; 2.23g and 1.16% in the first trial and 111.92; 3.16g e 28.49%, in the second). The number and the weight of no seed settings were significantly higher (P<0.05) in the plants covered with cages (416.29 and 6.58g; 375.25 and 5.04g in two trials) than in the control (142.69 and 1.71g; 182.38 and 2.53g). The percentage of seed setting in the bagged flowers with gauze was intermediate to the control plants and the covered plants. (64.56% in the first trial and 68.61%, in the second). It is concluded that the sunflower, cv Anhandy, presents a significant increase of seed production due to visits of pollinating insects, mainly honey bees. Cage is the most indicated method to protect plants from pollinating insects.
production increase; sunflower; pollination; Africanized honey bee; Apis mellifera