Apr. I, i9i8 Laspeyresia molesta. 6i 



from each of the early generations is separated from that occasioned by 

 the next generation by an interval during which no freshly injured 

 twigs can be found. This interval comes in the period between the 

 attainment of full development by the larvae of one brood and the ap- 

 pearance of the newly hatched larvse of the next. The interval between 

 the first and second generations and that between the second and third 

 are quite noticeable to one who is making observations in the orchard, 

 but after the third generation the broods of larvae overlap to such an 

 extent that they can not be thus defined. The injury resulting from 

 each successive generation increases in severity as the season advances, 

 until late summer. In 191 7 the number of moths produced by the 

 overwintering larvae appeared to be small and the amount of injury 

 from the first brood of larvae was proportionately so, only a few injured 

 twigs showing here and there through the peach orchard. The second- 

 brood injury was much more noticeable and the injury from the third 

 was quite severe. The fourth caused less damage to the twigs than the 

 third, while the fifth brood, appearing late in October, caused almost 

 no injury. In the latter part of the season the insects diminished in 

 numbers on trees without fruit and the overwintering larvae were few, 

 in comparison to the large number of larvae of the third generation and 

 the early part of the fourth. It was only on the trees bearing late- 

 ripening varieties of peaches or in the pome fruits that the larvae of the 

 fourth generation appeared to develop in large numbers. 



The injury caused by this insect is of two distinct kinds — namely, 

 injury to the twigs and injury to the fruit. The former is particularly 

 severe on young trees, and occurs mostly before midsummer, while the 

 twigs are yet soft; the latter form does not become severe until after 

 August I. 



TWIG INJURY 



The injury to the twigs is first noticed in the spring when the young 

 shoots are aibout 6 inches long. It is caused by the boring of the larvae 

 which enter near the tip of the twigs or in the petiole or midrib of the 

 leaves. The injury caused by the newl}^ hatched larvae may not be 

 noticed for several days after the insect has begun work if the weather 

 is cool and damp, but it appears much sooner if the weather is hot. 

 On peach it usually shows plainest at midday or in the afternoon and is 

 characterized at first by a slight wilting of a single leaf or in some cases 

 the whole tip of the twig and by a very small amount of frass thrown 

 out of the tunnel at the point of entrance. As the insect feeds it increases 

 in size and the tunnel is enlarged accordingly. As the tunneling pro- 

 ceeds the tip of the twig continues to wilt and finally dies. Usually 

 before the twig has completely dried the insect leaves it to find another 

 feeding place or to spin a cocoon if it has fully developed. A larva 

 seldom reaches full development in a single twig unless it be of the thick 



