1568 



ENCYCLOPEDIA OP PRACTICAL HORTICULTURE 



the crotch of a tree in Fig. 3 and again 

 one is sliown at the entrance to a burrow 

 containing larva m Fig 2. The larval 

 cell is also lined with silk. The silken 

 tube being merely a continuation of this 

 cell lining. Throughout the winter 

 months the hibernating larva remains in- 



Fiff. 



IIibeinatin£, Cliambei of Twii? Boiei 



active within this cell. A hibernating 

 larva magnified 26 diameters is shown 

 in Fig. 1. These larvae are exceedingly 

 well protected in their hibernaculae, 

 and Mr. Warren T. Clarke's experiments 

 in California show that they are almost 

 impenetrable to even an oil spray dur- 

 ing the winter season. 



In the spring of the year, about the 

 time the peach trees bloom, the larvae 

 leave their winter quarters and eat into 

 the tips of the twigs, either beginning 

 their work at the extremities or a short 

 distance below, sometimes hollowing them 

 out for usually a distance of less than 

 an inch from where the twig was entered, 

 leaving a mere shell or hollow cylinder 

 of the portion in which they have fed. 

 Again, they may merely gouge out the 

 tip of a twig on one side, entering in as 

 far as the pith and then leaving for some 

 other twig Thus they go from twig to 

 twig, feeding first in one and then in 

 another, until often the tips of a great 

 many branches will be killed back, there- 

 by checking their growth and more or 

 less injuring the tree. The detection of 

 their work is no difficult matter a short 

 time after they begin feeding, for the 

 leaves of affected twigs soon wilt and 



later dry up from the injury done to 

 them. 



The injury the first-brood larvae do 

 to twigs, while sometimes alarming, is 

 not usually to be compared with the in- 

 jury to the fruit from the second and 

 third broods. Often this injury to the 

 fruit is extensive enough to render great 

 quantities unmarketable. They usually 

 enter the fruit from the stem end and may 

 feed entirely within the flesh, but very 

 often eat their way into the pits. Af- 

 fected peaches may be detected by an 

 issuance of sap mixed with little pellets 

 from the fruit which have been chewed 

 up by the larvae. This sap hardens on 

 the outside and peaches so affected are 

 often termed ''gummy peaches." 



The Pupal Stage, — ^This stage of the 

 insect is said to last from six to twelve 

 days, the first brood remaining pupae 

 for the longest time. This period is 

 passed by the first-brood pupae, accord- 

 ing to Clarke, principally in curls of 

 bark on the trunks of trees in very flimsy 

 cocoons. They may, however, be found 

 in other places, such as between two 

 peaches which come in contact with each 

 other, under rubbish on the ground, etc. 

 The second and third-brood pupae more 

 often pupate in the suture at stem-end 

 of peaches than underneath the bark, 

 and the semblance to cocoons is even 

 less than in the case of the first brood. 



The Moth. — The twig-borer moth is a 

 tiny, gray insect, about % inch in length 



cota^^jemtsm- 



Fig, 3. Silken Tubes at Entrance to Larval 

 Chamber in Crotcli of Peacb Twig:. 



