Department of Entomology

Southeastern Apple Production ENTOMOLOGY

Tufted Apple Bud Moth

Platynota idaeuslais (Walker)

Description

Adult tufted apple bud moths (TABM) are 1/2 inch long, triangular, mottled gray moths with pronounced mouthparts extending beyond the head. Full-grown larvae are about 3/4 inch long and light brown to tan. Pupae are light brown, and eggs are laid on leaves in masses.

Adult

Larva

Pupa

Egg mass

Life History

TABM larvae overwinter on the orchard floor, then pupate and emerge as adults in late April. Eggs are laid from late May to June. First generation larvae primarily feed on foliage (though some larger larvae may feed on fruit by July). After pupating, these adults lay eggs which develop into second generation larvae that may attack fruit from August to September. See also graph below.

Damage

Larvae may skeletonize the underside of leaves close to the midrib, folding and webbing the leaf together. When larvae feed on the fruit surface, they often protect the feeding site with a web or leaf that is webbed to the apple. Larvae may also attack the cavities at the calyx and stem ends as well as the places where two fruit touch.

Skeletonized leaf shelter

Surface feeding

Monitoring and Control

Unless an individual orchard has a history of damage by this insect, it is doubtful that special precautions need to be taken. Timing is critical to the successful management of this pest. Depending on the type of insecticide used and the intensity of the TABM population, one or two applications during each of the two generations may be necessary. Maintain a clean orchard floor, particularly in the early spring before bloom, to minimize TABM populations by removing the food source for overwintering larvae. New apple sucker growth and broadleaf weeds are important food sources in the spring. In recent years TABM populations have been reduced to very low numbers because of new insecticides used in many orchards.

A TABM degree-day model similar to that of the Oriental fruit moth and codling moth has been tested and modified for populations in the Southeast. For calculating degree days from maximum and minimum daily temperatures, use the degree-day table below. Place TABM pheromone traps at the tight cluster to pink stage of bud development at a density of 1 trap per 20 acres of orchard. Biofix is the first date on which a sustained catch occurs and may vary from 2 to 15 moths per trap over a one-week period. The cumulative number of degree days from the point of biofix is used to predict percentage of egg hatch and to time insecticide applications against the first generation.

First-Generation Recommendation: When population densities are sufficiently high or if a short residual insecticide is used, two insecticide applications per generation are necessary; make the first application at about 10 percent egg hatch, which occurs between 800 and 900 DD after biofix, and the second application 14 days later. Where populations are low or if using a long residual insecticide, one application per generation should be made, and this can occur anytime between 10 and 30 percent egg hatch of the first generation, or from 800 to 1,200 DD after biofix.

Second-Generation Recommendation: Depending on variety and harvest date, make one or two applications for second-generation control. For cultivars harvested by early September, a single application at 10 percent egg hatch will usually suffice; this coincides with the accumulation of about 2,600 DD after biofix (early to mid-August). Second-generation egg hatch can sometimes extend into late September, so a second application may be made in late August or early September on varieties harvested after mid-September.

Typical TABM Pheromone Trap Catches and % Cumulative Egg Hatch

Insect and Mite Management Overview
Insect and Mite Index

Southeastern Apple Production
Mountain Horticultural Crops Research & Extension Center
455 Research Drive
Mills River, NC 28759
Phone: 828.684.3562 ~ Fax: 828.684.8715
Email: jim_walgenbach@ncsu.edu

Web Crafters: Anne S. Napier and Steve Schoof
Email: steve_schoof@ncsu.edu

Updated March 12, 2007