Seed Setting of Alfalfa Flowers Tripped by Bees and Mechanical Means1

A study was undertaken to determine the effectiveness of a locally built mechanical tripper and of leaf cutter bees, bumble bees and honey bees in bringing about tripping and seed setting in alfalfa Automatic or mechanical tripping followed by self pollination resulted in 31 6 per cent of pod formation and 1 7 seeds per pod When tripping was accompanied by cross pollination 74 8 per cent of the flowers formed pods and these pods contained an average of 4 7 seeds Bumble and leaf cutter bees tripped 90 2 and 61 0 per cent respectively of the flowers under observation In both cases the pods contained on the average 4 5 seeds which is proof that these bees cross pollinated when they tripped the flowers Honey bees were ineffective both as trippers and pollinators of alfalfa flowers There was an increase in the incidence of automatic tripping when honey bees had been in a cage for a period of five days The average number of seeds per pod under natural conditions was 4 4, proving that most of the pods set in the...