Codling Moth, Peach Twig Borer
July 11, 2005
First generation of codling moth is near the end in many sites in northern Utah and second generation egg hatch has begun in the warmest locations. Fruit should be protected through 920 degree-days (DD) after biofix (first moth catch) for the first generation. This DD number corresponds to 99% egg hatch. Egg hatch of the second generation begins at 1100 DD after biofix. Between 920 to 1100 DD, fruit protection is not necessary because no or very limited egg hatch is occurring.
Current codling moth development status for northern Utah sites:
- 2nd generation egg hatch has begun or nearly begun (0-1%) (1062-1125 DD); Fruit should now receive a fresh application of insecticide to protect it from hatching larvae of the 2nd generation: Salt Lake City Community College and West Valley City
- 99-100% of 1st generation eggs have completed hatching (945-995 DD); These sites are in between generations of codling moth and fruit is at very low risk from infestation, wait until 1100 DD and then apply a fresh insecticide application to protect fruit from 2nd generation larvae: Perry, Pleasant View, Kaysville, Central Orem, and Provo Bench
- 85-98% of 1st generation egg hatch is completed (677-908 DD); Fruit should remain protected through 920 DD; apply another insecticide application if residues have diminished: Logan, North Logan, River Heights, Alpine, Lincoln Point, Payson, Santaquin, and West Mountain
Peach Twig Borer
The 1st generation of peach twig borer is now completed in the warmest locations. Peach, nectarine, and apricot fruit should remain protected through 740 DD after biofix. Second generation egg hatch will reach 5% at 1200 DD when fruit protection should begin again.
Current peach twig borer development status for northern Utah sites:
- 1st generation is completed (800-1008 DD) and fruit protection isn’t necessary until 1200 DD: Perry, Salt Lake City Community College, and West Valley City
- 99% of 1st generation egg hatch is completed (750-761 DD); Fruit is at very low risk from new infestation, wait until 1200 DD to protect fruit from the 2nd generation: Kaysville and Payson
- 97-98% of 1st generation egg hatch is complete (691-721 DD); Continue to protect fruit until 740 DD: Lincoln Point, Central Orem, Provo Bench, and Pleasant View
- 34% of 1st generation egg hatch is completed (418 DD); continue to keep fruit protected until 740 DD: Logan
Greater Peachtree Borer
Greater peachtree borer moths have been caught in Grantsville in Toole Co. Moths have not been caught at other monitoring sites in northern Utah. Many of these sites have been treated with pheromone mating disruption in recent years, so moth populations are low and not reliable for detecting first emergence. Now is the time to place pheromone dispensers (Isomate-P) to disrupt mating and protect trees from infestation or to apply preventive trunk insecticides (Lorsban or Thiodan). A single Lorsban application or two applications of Thiodan (21 days apart) can protect trees for the entire season.
Cherry Fruit Fly
Keep cherry fruits protected for fruit flies through harvest. Insecticides with short preharvest intervals include spinosad (GF-120: 0 days; Success or Entrust: 7 days), carbaryl (Sevin: 3 days), imidacloprid (Provado: 7 days), malathion (1 or 3 days), permethrin (Pounce and Ambush: 3 days).
Precautionary Statement: All pesticides have benefits and risks, however following the label will maximize the benefits and reduce risks. Pay attention to the directions for use and follow precautionary statements. Pesticide labels are considered legal documents containing instructions and limitations. Inconsistent use of the product or disregarding the label is a violation of both federal and state laws. The pesticide applicator is legally responsible for proper use. Any mention of a pesticide brand in this document is not an endorsement by USU, and brand lists are not all-inclusive.