Blastodacna atra (Haw.) adult [from Balachowskky and Real 1966). 



Apple Pith Moth 



A New Apple Pest in New England 



]ofin S, "leaver and Alan T Eaton 



W^ith all the insect pests that are known to at 

 tack apple trees in the United States, most of 

 you tree growers are probably saying, "All I 

 need now is to have to deal with another 'Bug'! Well, 

 sorry to say it, but the Apple Pith Moth is here to 

 stay in New England and we are going to have to 

 learn to deal with it whether we like it or not. The 

 Apple Pith Moth, Blastodacna Astra (Haworth), was col- 

 lected for the first time in the United States in 1989 

 in Connecticut by Dr. David Wagner. Soon thereafter. 

 the coauthor (ATE) detected Apple Pith Moth caterpil- 

 lars and pupae in stems of damaged apple shoots, 

 and later reared them to adults. Subsequently, Apple 

 Pith Moth has been collected from a total of eight 

 counties in New Hampshire, as well as southern Maine 

 and Massachusetts. They do not yet occur north of the 

 White Mountains. Detection and control of Apple Pith 

 Moth can best be made by looking for the damage 

 signs of the caterpillars and taking proper corrective 

 measures at the right time of the year. 



DESCRIPTION 



The Apple Pith Moth, a micro-lepidopteran, is about 

 5-6mm (3/16") long, about the size of the lead at the 

 end of a pencil. Its minute size makes it rather diffi- 

 cult to identify without magnification. The moth's head 

 is covered with white scales. Its front wings are narrow 

 and mostly black with white marks and have (usually) 

 an irregular, faint, rusty-yellow line in the middle run- 



APRIL/MAY 1994 



ning from the base to the apex and two prominent 

 black scaly tufts. When the adult is in a resting posi- 

 tion with its wings folded together, it appears to have 

 three pairs of while wing spots: one near the base, a 

 second in the middle, and a third large pair covering 

 the ends. The pupae are golden brown, 5-6 mm long, 

 and with a dark head and a pair of unique paddle-like 

 projections at the end of the abdomen. The caterpillar 

 is 7-8 mm long, with young ones yellowish and older 

 ones more reddish in color. Under magnification, you 

 can see hundreds of very short setae (hairs) covering 

 the caterpillar. 



LIFE HISTORY 



in New Hampshire, females lay eggs individually 

 around the base of leaf axils on new shoots in luly. 

 Within two hours of hatching, the young caterpillars 

 bore into stems without causing much noticeable dam- 

 age, except for their tiny entrance holes which are sur- 

 rounded by rust-colored frass. In New Hampshire, the 

 entrance holes are noticeable during the first week in 

 August. Each caterpillar excavates an overwintering 

 shelter at the base of a bud, referred to as the 

 "logette", which is usually located just below the bark 

 surface, and is often shield-like in appearance. In 

 March and April, the larvae emerge from their cham- 

 bers and then locate and bore into new shoots. When 

 the trees are in blossom (15-20th May), the larvae are 

 actively feeding and pupae occur in june-luly and 

 adults in luly-August. 



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