Turfted Apple Bud Moth (TABM)

Although the pest is found in most commercial orchards in Pennsylvania, orchards in the south-central and southeastern portions of the state are more seriously affected.

Description and life cycle

The adult female moth is approximately ½ inch long, the male slightly smaller. Wing color is generally one-third grayish at the base, gradually darkening to brown at the tips, with a lightercolored 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 paleyellowish-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. 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. Firstinstar 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 grower 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

Insecticide resistance has made TABM increasingly difficult to control. Timing and coverage are of major importance in controlling this pest. Spray intervals should be shortened during early instar development. At least 100 gallons of water per acre should be used to attain good insecticide coverage. Some reduction in TABM populations may be realized by removing spring apple root suckers and suppressing ground cover under tree canopies. Techniques for estimating the potential injury at an orchard level and to time insecticide applications are presented below. This is followed by a ground cover treatment option and an insecticide resistance management plan.

Predicting TABM damage at harvest

Estimated fruit injury at harvest may be predicted based on the number of TABM males captured in pheromone traps in the first three weeks of the spring flight. Thus, pheromone trap captures can not only be used to determine when an intensive insecticide program should be applied, but if an intensive insecticide program should be applied against this pest. In many cases, where TABMs are not predicted to be as severe, one or more alternate row middle sprays may be eliminated from the program. Obviously, this can save pesticides, time, and money.
Type of trap. A commercially available wing-style or plastic delta-shaped sex pheromone trap containing a rubber septum dispenser loaded with synthetic TABM sex pheromone should be used. Be sure to follow directions for trap assembly and pheromone dispenser placement. Before attaching the trap bottom, spread the clear adhesive with a spatula so that it is evenly distributed.
Trap density and placement. At least two or three traps are needed for every block of Red Delicious or York Imperial block of 5 acres or less. Place one trap close to the orchard border and locate the others toward the center of the block. 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.
Trap monitoring and maintenance. Place traps in the orchard by May 1. 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 of TABM moths caught and remove them from the trap (or replace with clean trap bottom). Also remove any other debris. Spread the adhesive with the spatula and reset the trap. Those growers choosing to trap beyond 3 or 4 weeks after biofix should change the lures once a month or as suggested. Trap data later in the season are difficult to interpret at this time, although growers may wish to maintain a few traps to observe flight timing and relative pest abundance.

Predicting TABM damage in harvested apples

After the first TABM is caught, monitor traps for 3 weeks. At the end of the 3 weeks, total the number of TABM caught for each trap (“three-week cumulative catch”). Determine the average number of TABM per trap for each block if there are multiple traps in a block. To determine if a block needs to be treated with an insecticide for TABM, use the graph in Figure 2-4. On the horizontal axis locate the appropriate cumulative catch. Find the closest vertical grid line and follow it to the predicted line in the body of the graph. Then follow the closest horizontal grid line to the vertical axis to obtain a prediction of apple damage for that block.

If the predicted damage is too high for your apple marketing plans, an organophosphate, carbamate, insect growth regulator (IGR) insecticides (Intrepid or Rimon), ryanodine receptor agonist insecticide (e.g., Altacor, Belt or Voliam), or Delegate should be used:

• Use 5-day spray intervals for alternate row middles and 10-day intervals for every row middle. These sprays should begin (in an average year) on June 5 and end June 30 for first brood, and begin August 5 and end September 5 for second brood. Use the degree-day accumulation model described below for estimating the best time to begin applying insecticides for TABM control.
• Use the maximum recommended rates of insecticides for TABM found in Part V of this guide.
• Use at least 100 gallons of water per acre in the spray mixture. If predicted damage is not too high, then:
• Stretch spray intervals to 10 days for alternate row middles and 15 days for every row middle (use same beginning and ending dates as mentioned above).
• Use minimum recommended rates of insecticides for TABM as found in Part V of this guide.
• Use at least 50 to 100 gallons of water per acre in the spray mixture.

If Altacor, Delegate, Intrepid, or Rimon is used for the control of tufted apple bud moth larvae, no more than 2 complete precisely timed applications of insecticide per brood are recommended. To control first-brood TABM, make the first application of Intrepid or Rimon at 10 to 30 percent egg hatch (500 to 650 DD, base 45°F). If the second application is necessary, apply the insecticide at 60 to 70 percent egg hatch (800 to 850 DD). For second-brood control, apply Intrepid or Rimon at 20 to 30 percent egg hatch (2,355 to 2,435 DD) and repeat at 60 to 70 percent (2,665 to 2,740 DD). Do not use insecticides with the same mode of action for the control of both broods of TABM. Often, it is safer to reduce first brood sprays than second brood sprays.

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. Table 2-8 lists the percentage of eggs that are hatched for various degree-day totals for both broods of TABM. Tables 2-9 and 2-10 list the optimum spray periods for applying insecticides.

Table 2-11 gives degree days for TABM. To use these tables you must record the local temperature daily beginning at first TABM pheromone trap catch (see Environmental Monitoring in Orchards, Part I). If alternate row middle sprays are used, consult the first section of Table 2-9 to determine the best degree-day accumulation targets for each spray. If complete sprays are to be used, consult the lower section of Table 2-9. An insecticide application should be applied when a degree-day target is reached according to the measured orchard temperature conditions.

Asana XL ground cover treatment

Asana XL is registered for control of overwintering TABM larvae in apple and peach trees in Maryland, North Carolina, New Jersey, Pennsylvania, Virginia, and West Virginia. The label specifies a rate of 8.0 to 14.5 fluid ounces of product per acre in a minimum of 30 gallons of water per treated acre with the rate dependent on the size of the larvae and population pressure. The lower rate is advised at pink while the larvae are smaller and the higher rate at petal fall after the larvae have grown larger.

The application at the pink stage on apples is usually the most effective. However, growers desiring to use Asana XL at the pink stage should understand that it might affect Stethorus punctum adults that are emerging from the ground cover at this time. This predator overwinters in the same areas of the orchard ground cover as TABM and moves into apple trees from mid- April through mid-May when maximum daily temperatures exceed 65°F. Emergence from the ground cover is 20–70 percent complete by pink and 90–100 percent complete by petal fall of the cultivar Yorking.

Make applications in broad band from trunk to drip line since TABM larvae move out of the herbicide strip to find weeds to feed on. This insecticide treatment should only be used in problem orchards and then only in conjunction with proper management of TABM during the season. This material can be combined with a herbicide application or applied alone.

For peaches, application timings are similar to those for apples. Make an application at either the popcorn or shuck split stages at the same rates as for apples. Stethorus also overwinters in peach orchards, so the same cautions for apples apply to peaches.

Resistance management

Numerous TABM populations in south-central Pennsylvania have become resistant to many organophosphate and carbamate pesticides within the last 10 to 15 years. A strategy for counteracting this resistance is outlined on the next page.

1. Plant smaller block units of apple trees intermixed with other deciduous fruit trees to preserve refugia for susceptible individuals.
2. Practice good ground cover management within the orchard (e.g., eliminate broadleaved weeds and dropped fruit within the tree drip line) and apply Asana XL to orchard ground cover within the drip line at pink or petal fall.
3. Keep trees well pruned, remove water sprouts, and thin fruit properly.
4. Use correct application procedures (e.g., alternate row middle or complete sprays), calibrate sprayer to match tree size, and use the proper volume of water per tree to ensure coverage.
5. Spray only when economically necessary (i.e., use action thresholds based on sex pheromone traps or fruit injury) and use the lowest most effective rates compatible with IPM.
6. Use an egg degree-day model to properly time sprays to kill most susceptible stages (i.e., eggs and newly hatched larvae)—Do Not Treat For Large Larvae.
7. Alternate among insecticide classes between generations where possible, or use combinations of insecticide classes within generations to promote integrated mite management.

Chemical options are as follows:

• Use Bacillus thuringiensis products or Intrepid, Altacor, Delegate, or Rimon for one generation only, preceded or followed by another of these products (or another insecticide class) for the other generation.
• Use one of the above products for both generations within one season, and do not use for the first generation the following season.
• Use combinations of organophosphates and methomyl within a generation, preceded or followed by another insecticide class for the other generation.
• Alternate between organophosphates and methomyl between generations.