that must be pollinated, on a single 
flight. Pollenizers usually are 
interspaced between trees of the 
main variety. 
When appropriate pollenizer trees 
are not planted properly, other 
methods of supplying the needed 
pollen can be used. One substitute 
for trees is to graft branches of 
pollenizers to trees of the variety 
that must be pollinated. Grafts 
should be located where bees are 
most likely to visit—sheltered from 
prevailing winds, but exposed to the 
sun. 
At times, carefully preserved 
hand-collected pollen can be placed 
in a pollen dispenser in the entrance 
of a beehive. Bees leaving the hive 
will come in contact with the pollen 
and carry it to the flowers they visit. 
Reports on the use of pollen 
dispensers indicate that their use has 
not been consistently successful and 
often they are not recommended. 
To keep commercial pollen potent, 
follow all directions for its proper 
care. Hand-collected pollen is expen- 
sive and is generally used only as a 
last resort to get the plants pollinat- 
ed. 
Bees also are used to pollinate 
male-sterile plants that have been 
developed for mass producing hybrid 
seed of several bee-pollinated crops. 
Bees carry pollen from selected 
male-fertile plants to cross-pollinate 
the flowers of the male sterile plants. 
Some bee-pollinated hybrid crops 
are cucumber, onion, and squash. To 
produce these crops, every third to 
fifth row is planted to the male 
parent; the remaining rows are 
planted to the female parent. Similar 
methods are being developed for 
producing hybrid seed of cotton, 
melon, safflower, and some other 
field crops. In general, the bees are 
used on these crops the same way 
they are used on the other crops 
mentioned in this leaflet, although 
more colonies may be required to 
overcome the natural tendency of 
bees to work down the rows instead 
of across the rows. 
Pesticide Danger to Bees 
Pesticides are the single most seri- 
ous problem to beekeeping in agri- 
cultural areas. Many crops must be 
protected from insect pests and 
diseases, but they must also be pol- 
linated by bees. 
For further information on protect- 
ing bees from pesticides, consult 
your county or State Extension agent 
or your county or State bee inspec- 
tor. 
Revised March 1986 
