99 



is now entirely free from infestation. The waste from cigar factories 

 can be obtained cheaply for use in this way, and can be made into a 

 spray of the same strength as a 1 to 2,000 dilution of Black leaf 40 to 

 which may be added 6 lb. commercial flour paste jelly to 100 U.S. gals. 

 water and 10 lb. atomic sulphur. Though this treatment for root- 

 infesting forms of Aphids is still in the experimental stage, it is 

 considered worthy of recommendation to growers. 



Experiments in the control of Coccus citricola (grey scale) on citrus 

 trees in Tulare County again proved the superiority of fumigation over 

 sprapng. In spraying the bad effects are often not evident until the 

 following year, when there is frequently, as in the case of pyrox, more 

 or less severe injury to the smaller twigs, while the useful Coccinellid, 

 Novius cardinolis, is destroyed by it. 



Brock (A. A.). The Control of Walnut Aphis {Chromaj)his juglandi- 

 cola). — Mihly. Bull. Cal. State Commiss. Hortic, Sacramento, vi, 

 no. 11 & 12, November-December 1917, pp. 478-479. 



Considerable injury occurs to walnut trees in Santa Paula County 

 owing to the depredations of Chromaphis juglandicola, a heavy 

 infestation in one year usually being succeeded by a light one in the 

 following year. In 1917 the infestation promised to be very severe in 

 the early summer and spraying experiments were started as soon as 

 the conditions warranted treatment. Half a pint of nicotine sulphate 

 to 4 lb. whale-oil soap with 200 U.S. gals, water was found quite 

 efficacious in killing the Aphids, though a stronger solution acted more 

 quickly. Predators assist considerably in control of this aphis ; the 

 chief are the Coccinellids, Olla ahdomitialis and Psyllobora taedata, less 

 important ones being Coccimlki californica, Hippodamia convergens 

 and H. ambigua. In a moist season a fungus destroys this Aphid in 

 large numbers. The effect of sprapng showed that trees so treated are 

 much less damaged by hot weather than unsprayed ones, probably 

 because they put out new growth that protects the nuts. They were 

 also free from the sooty mould, which always follows the attacks 'of 

 C. juglandicola. A tobacco dust spray with lime or sulphur as a carrier 

 promises to be an effective and economical method of controlling this 

 pest, though the liquid spray is recommended as a better all-round 

 treatment in the case of severe infestation. 



VoLCK (W. H.). The Apple Leaf- mining Case-Bearer {ColeopJwra 

 volckei). — Mthly. Bull. Cal. State Commiss. Hortic, Sacramento, vi, 

 no. 11 & 12, November-December 1917, pp. 463-467, 6 figs. 



For several years past an unusual type of injury to apples in Pajaro 

 Valley, California, has been observed, one or more small punctures 

 appearing in the skin and extending a short distance into the pulp. 

 This injury was found to be due to a new species of case-bearing larva, 

 the hfe-history and habits of which were studied during 1916. The 

 presence of the insect on the fruit is evidently accidental, the foliage 

 being the principal food. The first eggs were observed in the laboratory 

 in early July ; they are placed on the under-side of the leaves among the 

 plant hairs and are so small as to be difficult to find. The fiat side of 

 the egg is tightly pressed against the leaf -surface, and upon hatching 



