15 



If plum root is or is not attacked, we have not been able to prove con- 

 clusively, as we did not see but very few trees as plum root in the immedi- 

 ate neighborhood, but there is strong probability that both plum and apricot 

 are resistant. This matter requires thorough investigation, and I intend 

 to try the experiment of colonizing the borer on plum root. The grub or 

 larva is pinkish when alive; the chrysalid is brown, sperm of the eatings 

 and borings of the wood. When emerging from its chrysalis state, the 

 moth reaches the surface, and its last skin is often seen protruding. 



DEVELOPMENT. 



This species requires evidently a year for its full development, and as the 

 moth appears in May and June, the egg must be laid in that time. These 

 are laid just below the surface, and the reason that so few worms are found 

 on sandy soil, is probably because in ovipositing the female has to push 

 the abdomen in the ground; when it finds that the soil falls in, its instinct 

 leads it to avoid such places. 



REMEDY. 



Planting in sandy soil or replacing the natural soil with a basin of fine 

 sand, will probably prove a very good preventive of infection. The sand 

 should be placed at least to the depth of four inches. A method recom- 

 mended in the East for the peach borer found there, is the wrapping of a 

 stout piece of paper around the trunk to the depth of six inches, and two 

 above, this to be held in place by a collar of mortar. Gaslime, which has 

 been recommended for this purpose, is too dangerous; while it might do no 

 harm during the summer it would invariably result in danger to the tree, 

 if thoroughly wetted and the solution was percolating down the trunk. 

 Indeed, I have already learned of damage from its use. In my recom- 

 mendation of using gaslime for woolly aphis on the apple tree, I have 

 invariably warned against putting it against the trunk. In this case the 

 material to be successfully used must be placed against the trunk. Air- 

 slacked lime, however, may be used without any injury, but should be put 

 on in the spring, after the heavy rains are over; in the early part of April. 



It being a settled fact that this insect is new to science (named by Pro- 

 fessor Riley, Sannania pacifica) , we must look for its original food plants 

 in this State. I have spent a little time in looking over the creeks adjoin- 

 ing the infested district, but have failed to find any wild trees infested, but 

 I shall continue this investigation further next spring, as it is of consider- 

 able importance to know the wild tree this borer inhabits. My conclusion 

 is that it probably lives on one of our wild cherries (perhaps Prunus 

 demissa) , but owing to the fact that the soil generally is sandy along water- 

 courses, and the trees of a kind are few and far between, the food for the 

 borer has been restricted, so that very little increase took place until 

 orchard planting commenced in the vicinity. 



There is no question that the insect may be spread on nursery stock. 

 The eggs being laid in the bark, and the trees coming from suspected quar- 

 ters should be thoroughly scrutinized, and at least thoroughly disinfected 

 by dipping in caustic solution. So far I have only found this insect in the 

 locality mentioned, two and one half miles southwest of San Jose, but being 

 a native insect we may look for it in all the orchards along watercourses in 

 the coast valley. 



The mature insects, male and female, are distinguished from the eastern 

 species by the absence of cross bands of the abdomen, which are of a black 

 steel blue. 



