414 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



the galleries being full of them. If examined in mid-winter there are fewer 

 beetles and a larger number of males. 



(1) Remove infected branches in early September and burn them. 



(2) Dress the trees with (a) clay and lime, (b) soft soap and soda, or (c) 

 clay and lead arsenate in early March. 



(3) Drive newly cut oak or hawthorn stakes in between the trees, and 

 burn them in June. 



Scolytus is a bark-borer, and both larvae and beetles bore. 



There may be two or three broods in a year, and the first attack is in April 

 or May, at its height by June, and a new brood has reached maturity in August. 

 The holes are no larger than pin-pricks, and are not so fatal to the tree as Xyleborus. 

 It will breed in timber a long time felled, so " trap trees " may be stakes of 

 fruit trees. — G. F. W. 



Slug, The Spotted Garden. By W. H. White (U.S.A. Dep. Agr., Farm. 

 Bull. 595, June 191 8 ; 3 figs.). — Describes the habits of the spotted garden slug, 

 and explains how to rid the premises and grounds of this destructive pest. The 

 standard remedies are lime, salt, soot, sand, and road dust. Poisoned baits of 

 boiled potato sprinkled with arsenic are good, and it is imperative that gardens, 

 greenhouses, and mushroom beds should be kept clear of weeds, rubbish, and 

 other breeding-grounds and hiding-places. — V. G. J. 



Smyrna Fig Culture. By W. Taylor (U.S.A. Dep. Agr.-, Bull. 732, pp. 1-43, 

 10 figs.). — The Smyrna fig is grown in large quantities in California. It appre- 

 ciates a well-drained loam, dressings of stable manure and some irrigation, and 

 requires little pruning. As the Smyrna fig is female, it is essential that the 

 orchards contain some Capri figs. The pollination of the Smyrna fig is effected 

 by means of an insect, Blastophaga grossorum, which gains access through the eye 

 of the fig to the female organs. This insect hibernates in the Capri fig ; in 

 fact, only a few hours of its existence are spent outside the Capri fig. In June 

 baskets or chaplets of Capri figs are suspended in the Smyrna fig trees, to facilitate 

 pollination. The unfertilized fruit does not develop and falls to the ground. 



5. E. W. 



Soil Acidity and Effects of Moisture upon it. By S. D. Conner (U.S.A. Jour. 

 Agr. Res. vol. xv. No. 6, Nov. 1918, pp. 321-330). — Five different types of 

 acid soils were kept under different moisture conditions in pots for over one 

 year. Portions of the soils were a quarter saturated, half saturated, and fully 

 saturated ; also in an air-dry condition. The acidity determinations were 

 made by Hopkins' KN0 3 method, Jones' calcium acetate method, and ethyl 

 acetate method, and samples of soil from each pot were tested for acidity both 

 in moist and air-dried condition. . The author found that soil rich in organic 

 matter showed the greatest acidity when kept fully saturated ; the soils low in 

 organic matter showed the greatest acidity when kept half-saturated. With 

 mineral soils the fully saturated soils had much greater amounts of soluble 

 manganese than the other samples. There is less soluble aluminium in fully 

 saturated mineral soils, but with soils high in organic matter this does not hold. 

 Calcium, magnesium, and silica showed variations in solubility owing to different 

 moisture conditions, but the variations are not so marked as those of iron, man- 

 ganese, and aluminium. In correlating the soluble iron and aluminium with 

 the acidity obtained from KNO a extracts, the titrated acidity is partly due to 

 soluble acid organic compounds. The acidity varies under different conditions 

 of moisture and aeration, and these variations are due to chemical rather than 

 physical changes in the soils. Acidity in humid soils is produced by the leach- 

 ing of strong basic elements in drainage water, by removal of bases in crops, 

 by the decay of carbonaceous and nitrogenous substances, and by the hydrolysis 

 of mineral compounds and organic matter. — A . B. 



Soil, Ammonification of Manure in. By H. J. Conn and J. W. Bright 



(Jour. Agr. Res. xvi. No. 12, March 1919, pp. 313-350). — The importance of 

 ammonification process in the soil has long been recognized, though there is 

 a tendency to regard it as of secondary importance to nitrification in soil fertility. 

 The present paper is an attempt to determine the organisms which cause the 

 ammonification of manure in soil under natural conditions, and to compare them 

 with other organisms known to possess this power under laboratory conditions. 

 The authors find that the non-spore-forming bacteria are most active in manured 

 soil, and of these Pseudomonas fluorescens (Fliigge) Migula and P. caudatus 

 (Wright) Conn are the most active. Pure cultures of both organisms multiply 

 much more rapidly in sterilized manured soil than do pure cultures of B. cereus 



