Spraying fruit trees for worms

Asked March 9, 2020, 5:07 PM EDT

I have a pear tree that gets worms in the fruit every year. It is currently budding but hasn’t flowered yet. Is it too late to spray insecticides for fear of killing bees? What type of spray do you recommend? What type of service can you hire just for spraying?

Washington County Oregon

1 Response

Yes, you still have time to spray.

But, If you have worms in your pears, the first thing we must do is determine which one is causing the problem. The most likely candidate is codling moth. Read the following information to determine if that’s accurate. If it’s not, please reply to this email so that we can switch to Plan B.

The youngsters of codling moth (caterpillars) typically bore from the outside of the fruit and continue to the core where they remain. They’re a very common pest of apples but also infest pears, especially where two pears touch each other.

“Codling Moth” discusses the lifecycle and habits about the pest in apples but the principles are easy to apply to Asian pears. (See http://ipm.ucanr.edu/PMG/PESTNOTES/pn7412.html)

The management section of the above document lists multiple cultural tactics which will supplement chemical treatment. Among them are to place a band of corrugated cardboard around the trunk; protecting individual fruits with either footies or small paper bags; plus sanitation (collecting and discarding) all damaged fruit.

Chemical management is clearly defined in a newly revised publication -- “Managing diseases and insects in home orchards” (EC 631; https://catalog.extension.oregonstate.edu/sites/catalog/files/project/pdf/ec631.pdf)

Management, both cultural and chemical, is on pages 7 and 8. An image of the external effect of codling moths on pears is at the top right, page 7 whereas internal damage on apples (the same as on pears) is pictured on page 5.

From the above publication: “Use pheromone traps to time the first spray accurately, or check with your local Extension office for information. Place traps in the upper third of the canopy ahead of bloom.”

Consider phoning nearby large garden centers to determine which one carries codling moth traps. Farm stores may be the best source.