Tree Fruit Insect Pest -Tufted Apple Bud Moth

The tufted apple bud moth, Platynota idaeusalis, is a serious direct pest of apples in the five-state Cumberland-Shenandoah region of the eastern United States.
Tree Fruit Insect Pest -Tufted Apple Bud Moth - Articles

Updated: October 25, 2017

Tree Fruit Insect Pest -Tufted Apple Bud Moth

The tufted apple bud moth is named for the tufted scales that can be seen as two or three groups on the tops of the wings. Photo by G. Krawczyk.

Over the last 15 years it has become rather a minor pest. Initially, this was due to the introduction of leafroller-specific insecticides such as Confirm and Intrepid, but more recently it is due to products such as Altacor, Belt, Delegate, etc., which are targeted for codling moth but give long residual control of this and other leafroller pests as well.

Description and life cycle

The adult female moth is approximately ½ inch long, the male slightly smaller. Wing color is generally grayish at the base, gradually darkening to brown at the tips, with a lighter-colored margin along the leading edge of the wings. The moth is named for the tufted scales that can be seen as two or three groups on the tops of the wings. Moths are extremely well camouflaged on tree trunks.

Larvae are a light brown to grayish tan with a chestnut-brown head capsule, a darker prothoracic shield (hardened area between the head and body), and a dark stripe down the back of the body. This coloration distinguishes TABM larvae from various other leafrollers. The redbanded leafroller has a pale green body with a yellowish green head; the obliquebanded leafroller has a yellowish green body with a brown to black head and a pale-yellowish-green to black prothoracic shield; and the fruit-tree leafroller has a translucent apple-green body with a reddish to dark brown head and an amber prothoracic shield. Bud moths deposit their eggs in an ovoid apple-green mass consisting of as many as 150 eggs or more. The mass is usually deposited on the upper leaf surface, and along a leaf vein.

TABM produce two generations per year. Larvae overwinter as second through fourth instars in shelters such as leaves and decaying fruit beneath trees in apple, cherry, peach, and pear orchards and in woods. The larvae become active in early spring and complete their development on root suckers or various broadleaf weeds such as dandelion, dock, and wild strawberry in the ground cover. The larvae pupate and emerge as adults around the beginning of May. They start laying eggs about the beginning of June. First-instar larvae disperse by crawling or ballooning (floating on the wind). First and second instars then feed along a leaf midrib, and, beginning with the third instar, create shelters by rolling leaves, tying leaves to other leaves or fruit, and building shelters within fruit clusters. Larvae generally pupate within these shelters, emerge as adults, and begin second-brood egg-laying about the beginning of August. Late season, second-brood larvae (second through fourth instars) drop to the ground to overwinter as leaves fall in autumn.

Although TABM belongs to a family of moths known as leafrollers, the leafrolling activity has little economic impact on the fruit growing operation and little physiological impact on the tree. It is when this insect webs a leaf onto the apple and feeds directly on the fruit that it becomes a pest. Damage appears as tiny holes (early instar feeding), as irregular scarring or gallerying of the apple surface, or as an area of rot, generally found around the stem. Rot or corking around the stem occurs usually after the larvae have finished feeding and have pupated. Larvae occasionally enter the apple calyx and feed unnoticed within the seed cavity. Most damage to apples is caused by second-brood feeding, although in some years first-brood damage can exceed that caused by the following generation. Damage to fruits destined for fresh markets has a greater economic impact, since their cash value is much higher than that of processing grade apples. Generally, TABM injury does not reduce the grade of processing apples, but it can affect the storageability of those apples by promoting decay.

Monitoring and management

A commercially available plastic delta-shaped sex pheromone trap containing a rubber septum dispenser loaded with synthetic TABM sex pheromone should be used. At least two or three traps are needed for every block of apples of 5 acres or less. For blocks greater than 5 acres, use three or more traps. Each should be attached to a limb at a height of 5 to 6 feet in the outer third of the tree canopy. Place traps in the orchard by bloom of apples. Check traps every day until the first TABM adult is caught, and record this date. Thereafter, check the traps on the same day once a week (traps should be checked and cleaned more frequently during high TABM pressure so the trap bottom does not become clogged with moths and unable to trap anymore). During each visit to the trap, record the number moths caught and remove them from the trap (or replace with clean trap bottom). Also remove any other debris.

Similar to the case of the spotted tentiform leafminer, the importance of this pest has greatly diminished due to the introduction of a number of codling moth control products that have excellent residual control of the tufted apple bud moth even if codling moth sprays are not ideally timed for TABM control. If TABM damage from the previous season is too high for your apple marketing plans, a controls be applied at approximately third cover or as close to sometime in the first 2 weeks of September. Both timings will also enhance control of oblique- and redbanded leafrollers.

Predicting TABM egg hatch based on degree days

A close relationship exists between the number of accumulated degree days beginning with first pheromone trap capture of an adult tufted apple bud moth and egg hatch for both first and second brood. This means that by monitoring orchard temperatures on a daily basis, a fruit grower can confidently predict the best time to apply an insecticide. The egg hatch prediction can be used in conjunction with, or independent of, the fruit damage prediction method. The egg hatch period is a time when the larvae of this pest are most susceptible to insecticides.

Authors

Insect plant interactions Integrated pest management Biological control Tree fruit insect pests Insects rearing Laboratory and field bioassays Invasive insect pests Pesticide resistance

More by Grzegorz (Greg) Krawczyk, Ph.D.