By Darrell Blackwelder
For the Salisbury Post
Beginning gardeners planting crops such as cantaloupe, watermelon, squash and cucumbers and other cucurbit crops need to know that these crops are very much dependent upon insects for pollination.
Without honeybees and other pollinating insects, these vegetables produce poor quality or no fruit at all.
Vining cucurbits such as cucumber and winter squash have separate male and female flowers on the same plant. Male flowers bloom first and are very abundant. Female flowers producing the fruit bloom shortly afterwards. Female blooms have a short period to which they are receptive to pollination.
Research shows that the female flowers are receptive to pollen for only 24 hours. For some reason, if pollination dues not occur, the flowers wilt and shed off.
Pollination of cucurbits can not occur without bees. Pollen from the vine crops is sticky, requiring physical removal from flower to flower. Honeybees are very important in the pollination process. Honeybees pollinate flowers generally from 10 a.m. to 2 p.m. during the day.
It may take as many as 12 visits from honeybees or other insects for proper pollination to occur. Honeybees require almost perfect conditions before flying to pollinate vine crops. The temperature must be close to 70 degrees, wind should be less than 15 mph and the humidity should be less than 75 percent. Honeybees do not fly in rainy, cool weather.
Commercial squash producer’s yields are almost nil after a period of cool weather or if other plants attract bees. Some producers have reduced crops when tulip poplars bloom. Bees resume flights when normal summer weather returns.
Commercial vegetable producers often rent bee colonies from beekeepers to pollinate cucurbit crops. One colony of honeybees may contain up to 40,000 bees. These bees can pollinate an acre of vine crops.
Local greenhouse tomato producers often employ bumble bees to reduce their labor and pollinate tomatoes. Bumble bees fly and pollinate under adverse conditions during which honeybees will not fly. This is an attribute which makes them a desirable worker during cool, wet conditions, however, the expense makes bumble bees impractical for pollinating field crops.
Home gardeners must protect these beneficial insects to produce good quality crops. Only use pesticides as a last resort to control an insect. Spray very early or late in the evening and always read the label before applying any pesticide.
Darrell Blackwelder is at Extension agent in horticulture at the Rowan County Cooperative Extension Center. Contact him at 704-216-8970.
Web sites:
http://www.rowanmastergardener .com
http://rowan.ces.ncsu.edu
http://rowanhorticulture.blogspot .com/