'Bee' mindful of pollinators when spraying fruit crops

Michele Warmund, 573-882-9632

COLUMBIA, Mo. – Bees are a fruit tree owner’s friend and need special protection from pesticides, says University of Missouri Extension horticulturist Michele Warmund.

Bees are essential to pollinate many fruit crops, including apple, pear, Japanese plums, sweet cherries, blueberry and elderberry, says Warmund.

“Bees transfer pollen from flowers of one fruit tree to blossoms of another to begin the process of pollination and subsequent fruit set,” she says. “It is important to protect them during the bloom period.”

Honeybees, native bees and other beneficial insects face risk from pesticides. Foraging bees endanger the brood when they bring pollen from sprayed flowers back to the hive.

Warmund suggest these easy precautions to protect bees from pesticide application during fruit tree bloom:

• Plant pest-resistant cultivars.

• Scout weekly for insects and diseases.

• Apply pesticides only when numbers are high enough to severely reduce yield or if the tree may die or be damaged.

• Avoid mixing chemicals that are more toxic to bees than individual products.

• Watch for pesticides that are labeled “harmful to bees” or “residual toxicity.”

• Avoid applying during the bloom season.

• Avoid applying when honeybees are most active – two hours before sunrise and one hour after sunset; they may forage earlier or later when it is hot.

• Mow nearby flowering weeds that attract bees, such as dandelions. If you can’t mow, clip blooms before applying pesticides.

If a fungicide is necessary during pollination, avoid products containing captan, ziram or iprodione, which can affect brood development, says Warmund.

When possible, limit or avoid products that recommend adding adjuvants or surfactants to the tank mix. Some think that some adjuvants and surfactants make it easier for pesticides to penetrate the bee’s outer cuticle.

Another option is to plant self-pollinating fruit trees and plants to reduce the need for bees. For example, peaches, nectarines, sour cherries, apricots, European (blue) plums, grape, strawberry, blackberry, raspberry and gooseberry do not solely require pollinators for fruit set, even though fruiting is enhanced by bee activity during the bloom period. These types of fruits reduce the need for bees to pollinate.

Related MU Extension publications available for free download:

• “Honey Bees as Pollinators, Their Habitats and Products,” extension.missouri.edu/m403.

• “Pollinating Fruit Crops,” extension.missouri.edu/G6001.

MU Extension’s Master Pollinator Steward program offers classes with information about protecting pollinators, including honeybees, native bees, butterflies, flies, beetles, birds and bats. Learn more at extension.missouri.edu/programs/master-pollinator-steward. Six-week sessions begin in May.