Insect repellent applied to pants and legs can keep the pests away. Some fruit tree cultivars cannot pollinate their own flowers. These are considered self-unfruitful. In order to obtain fruit set, another cultivar of the same fruit is needed for cross-pollination. Most apple and pear cultivars are self-unfruitful.
Some apple trees are better pollinators than others are.
A new bulletin at the Extension Office on Pollination includes a chart for the best pollen source for different apple cultivars. Because sweet corn is pollinated by the wind, better pollination occurs when it is planted in short blocks of three or four rows rather than a single long row. Cross-pollination by field corn, popcorn, broomcorn, Indian corn, and standard sweet corn varieties will reduce the quality of the high sugar sweet corn varieties. Corn varieties can be isolated from cross-pollination by having different pollination times or isolating cultivars by a distance of at least 250 feet. If the planting is upwind, a distance of 100 to 150 feet may be adequate.