STATE HORTICULTUEAL SOCIETY. 95 



are almost microscopic insects, and the species are extremely difficult 

 to distinguish one from the other. It would be really impossible 

 for any one but an expert entomologist to identify positively the 

 apple-louse if found on any plant but the apple, and even he would 

 probably withhold a decision until he had verified his conclusion by 

 transferring the insects to the apple, and causing them to breed there 

 and bring forth oviparous progeny. There is this practical point to 

 the Cjuestion I have raised. It is quite possible that the apple-louse 

 infests in midsummer some worthless plant which could be easily 

 destroyed, and the insect with it, — or that it breeds then on some 

 cultivated plant, the proximity of which to the apple nursery in- 

 creases the probability of attack by the apple-louse and makes that 

 attack more severe. I add here another suggestion (made to me by 

 one of my assistants. Mr. Weed), that possibly the best time to de- 

 stroy the apple-louse is in fall, when the last generation of the year 

 are still young and tender on the undersides of the leaves. In 

 spring the young leaves curl so readily when infested that the lice 

 are thus almost wholly protected against fluid or powdery applica- 

 tions, and they then multiply so rapidly, generation after generation, 

 that if only a few are left on here and there a leaf it may be but a 

 little time until they are almost as numerous as before. In autumn, 

 however, the full-grown hardened leaves do not curl, under the 

 plant-louse injury, and there is then but a single generation of the 

 lice followed by the eggs; spraying of the trees at this season with 

 the kerosene emulsion would consequently take much greater effect 

 upon these almost unmanageable insects than it would in spring. 



Next I beg to inquire concerning the occurrence of the apple 

 maggot in the apples of this State. It has never yet been reported 

 to infest our fruit, although it is one of the worst of the insects de- 

 vouring the apple in the Eastern States, and is especially destructive 

 at least as far West as Michigan. It has long been known to occur 

 within our limits, feeding here particularly upon the thorn apple or 

 red haw, from which, in fact, it was described by Walsh, twenty 

 years ago, in his first report. It is consequently a very surprising 

 fact that it has not long ago attacked our apple as in the East. The 

 thorn apple is, however, naturally its favorite food, and Prof. Cora- 

 stock reports an instance where it was found abundantly infesting 

 this fruit near Washington, beside an apple orchard in which no 

 evidence of its presence was delected. Still it must have been 

 shipped in to us repeatedly in the early apples from the Eastern 

 States, and it is quite possibly working us serious injury under cover 

 of the better known damage inflicted by the codling moth. The 

 work of the two species might, in fact, be easily confounded by one 

 whose attention had not been called to the difference. The larva of 

 the codling moth or apple worm is a small caterpillar with distinct 

 head and eight pairs of legs, whereas the apple maggot is footless 

 and headless, pointed at one end and blunt or truncate at the other, 



