Yes, it is spring here in Sevier Valley, but sometimes it makes you wonder. Some days it feels like summer and others it’s like winter and then there is the wind. It has been a historically dry winter and spring. The erratic temperatures make it a real challenge to grow garden, orchard and field crops.
As of Friday, our office has received the latest prediction report from Dr. Marion Murray, Utah State University Extension integrated pest management specialist.
Murray uses a system of orchard based pheromone monitoring traps, weather stations that record duration of temperatures and a computer based prediction model that accurately predict when it is time treat. This year that day for Sevier Valley is about May 25. If you apply an insecticide around May 25, you should prevent an infestation of worms in your fruit. The insect that causes the problem is the Codling Moth. The adult lays the eggs that hatch into the worms (larvae) that attack the fruit of apples, pears and other fruit beginning in late May and early June.
Some years we have needed to spray insecticides as early as about May 15. Other years it has been as late as about June 4. It all depends on how much and when we get warm weather.
Many places in Sevier Valley were in the teens just about a month ago and many of the fruit tree blossoms were frozen. Some apples, pears, peaches and cherry blossoms survived, and the fruit is now developing. Before you apply the first routine spray, it would be a good idea to check and make sure you have enough fruit surviving on the tree to justify protecting it.
The Codling Moth female lays eggs on leaves or fruits. The eggs then hatch becoming larvae or worms that usually get into the fruit through the blossom end. They chew their way into the fruit where they feed until maturity. Once mature, the larvae leave the fruit, making an exit hole. They become the next generation of moths to lay more eggs and continue the cycle.
This is the first spray application that needs to be done in the year. Because of the length of the hatch and overlaying with the second generation fruit should be continually protected until mid-to-late August. In addition, cleaning up wormy apples that have fallen from the tree will greatly reduce insect number for later in the season and next year.
There are many different insecticides and cultural control methods that control the codling moth. Please visit pestadvisories.usu.edu/2018/05/14/cm-updated/ for an updated list.
The USU Extension Office is located at the Sevier County Administration Building, 250 North Main in Richfield. For more information, please contact Jody Gale at (435) 893-0470.