By Darrell Blackwelder
It is very important for beginning gardeners planting vegetables such as cantaloupe, watermelon, squash and cucumbers and other cucurbit crops to know that these plants depend on 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 in 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 cannot occur without bees and other insects. Pollen of these crops is sticky, requiring physical movement from flower to flower. Honeybees are very important in the pollination process. Honeybees do most of their pollinating from 10 a.m. to 2 p.m. during the day.
It may take as many as 12 visits from honeybees or other insects to ensure proper pollination. Honeybees require almost perfect conditions before flying to pollinate vine crops. The temperature must be warm, the wind less than 15 mph and the humidity should be less than 75 percent. Honeybees generally do not fly in rainy, cool weather. Honeybees resume flights when normal summer weather returns.
Commercial squash producers’ yields are reduced significantly after a period of cool weather or if other plants are in bloom. Some producers have reduced crops when tulip poplars are in bloom.
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.
Greenhouse tomato producers often employ sterile bumblebees to reduce their labor and pollinate blooming tomatoes. Other bees and wild bumblebees pollinate under adverse conditions when domesticated honeybees will not fly. This attribute makes them a desirable worker during cool, wet conditions; however, the expense of this type of pollinator is impractical for pollinating commercial field crops.
To produce good quality crops, home gardeners must protect these beneficial insects. 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 the county extension director with Cooperative Extension in Rowan County. Call 704-216-8970 or visit http://