BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE 49 
Honey Bees Affect Cotton Flower Development 
In studies on cotton pollination made in Arizona, flowering cotton 
was enclosed in large plastic screened cages. In some of the cages 
colonies of honey bees were placed. Bees were excluded from other 
cages. In the cages with bees all the new (white) flowers that opened 
on any one day were pink by 5 p. m. and almost completely closed. 
In the cages without bees the new flowers were still white and flared 
open. This may be a factor of practical importance to cotton growers 
in areas where afternoon showers are common, since earlier closing 
of the flowers should afford increased protection to the stigma. It 
may also be a guide to cotton breeders in determining the proportion 
of natural crossing in open fields. 
Huge Numbers of Bumble Bees Assist in Pollinating Red Clover 
At Columbus, Ohio, the largest bumble bee population observed in 
several years was of material help in pollinating red clover, supple- 
menting the work of honey bees moved into the field. Unfortunately, 
there is no means at present of maintaining the number of bumble bees 
from year to year at a constant level. 
Competitor Plants Reduce Effectiveness of Bees as 
Red Clover Pollinators 
Competitor plants can greatly reduce the effectiveness of honey 
bees in the pollination of red clover. In Delaware County, Ohio, for 
example, difficulty was experienced in obtaining adequate pollination 
of red clover by honey bees since nearby ladino clover attracted most 
of the pollen-collecting honey bees while nectar-collecting bees visited 
alfalfa. Even increasing the number of bees to 7 colonies per acre 
did not entirely correct the difficulty because of the large acreages 
of the competing plants. 
Improved Harvesting Methods Necessary to Reap Benefits of 
Bee-Pollinated Red Clover 
Harvesting losses of red clover seed in Ohio were heavy although 
weather conditions were unusually favorable for such operations. In 
one instance it was found that the combine discarded into the refuse 
43 percent of the seed in the field. Such losses, or greater ones, appear 
to be the rule. Consequently, it seems certain that with the use of 
adequate numbers of honey bees for pollinators, red clover seed pro- 
duction in Ohio could be increased from 50 to 100 percent by a mod- 
erate improvement in harvesting efficiency. 
Insect Pollinators of Alfalfa Vary with the Locality 
Field studies in Nevada, Utah, and Washington showed that insect 
pollinators of alfalfa vary with the locality. In the lower Yakima 
Valley of Washington, southern Millard County of Utah and in the 
Uintah Basin, alkali bees (Norma) were the principal pollinators. 
In the Delta tract of Millard County, honey bees were the principal 
pollinators, except for scattered localities containing Norma nesting 
