Insect Pest Not So Pesky

January 29, 2002

WOOSTER, Ohio - The strawberry bud weevil, an insect that feeds on strawberry plants, may not be as much of a concern as once originally thought.

Though labeled a pest because of the considerable damage the insect can do to strawberry plants, entomologists have found that the strawberry bud weevil, commonly known as the clipper, restricts its range along a field's edge, making it easier to control the insect through smaller, more economical pesticide applications.

"Monitoring weevils in unsprayed fields over a three-four year period showed that the insects move only about 8-10 meters (24-32 feet) per year," said Joe Kovach, of Ohio State's Integrated Pest Management program. "The pest occurs more often on the edge of the field rather than the center, so why spray a whole field if you can effectively control it by just spraying along the border?"

In addition, researchers found that the damage the insect does to a bud may contribute to an increase in the size of the fruit that is produced. The strawberry bud weevil feeds on unopened flower buds, preventing them from developing, and hence producing little or no fruit. Research has shown that this clipping results in bigger fruit size from the remaining buds on the plant.

Kovach, a researcher with the Ohio Agricultural Research and Development Center in Wooster, Ohio, will discuss these latest research findings at the Ohio Fruit and Vegetable Growers Congress and Ohio Roadside Marketing Conference, Feb. 6-8 in Toledo, Ohio.

"Some fruit, like apples, are compensators. That is, they produce bigger fruit when their buds are removed," said Kovach. "Recent research has shown that strawberry plants do the same thing."

Studies have indicated that if the primary bud is clipped, the secondary bud produces bigger fruit. Additionally, if the secondary bud is clipped, the primary and tertiary buds produce bigger fruit.

"We think it takes a lot of energy to open that flower bud. If a bud is clipped before it opens then that energy is allocated to other unopened buds, hence producing larger fruit," theorizes Kovach.

Kovach stated that some strawberry cultivars are better compensators than others. Seneca topped the list of 11 compensating cultivars, with a 44 percent increase in fruit size after clipping the primary bud. Mohawk, Mira and Jewel followed with 20-25 percent increase in fruit size. Other cultivars, such as Lateglow, Earliglow and Cavendish rounded out the list with 10 percent or less increase in fruit size.

"These results tell us that maybe growers should plant strawberries that compensate for clipper injury in border rows of the field, so bigger fruit is produced with minimal yield loss. And then plant non-compensation cultivars in the middle of the field," said Kovach.

Kovach stated that farmers might not have to spray as much on compensating cultivars to control the insect and recommends that farmers wait until at least one clip is present on a primary bud or up to 20 on secondary and tertiary buds in order to continue producing a successful crop.

The Ohio Fruit and Vegetable Growers Congress and Ohio Roadside Marketing Conference is designed to provide fruit and vegetable growers the latest in research information, food safety and labor regulations, and economic opportunities. The conference is sponsored by Ohio State University, Ohio Vegetable and Potato Growers Association, Ohio Fruit Growers Society, and the Direct Agricultural Marketing Association of Ohio. For more information on the conference contact the Ohio Fruit and Vegetable Growers office at (614) 249-2424, e-mail growohio@ofbf.org, or log on to http://www.ohiofruit.org or http://www.ohiovegetables.org.

Author(s): 
Candace Pollock
Source(s): 
Joe Kovach