150 



THE GARDENERS' CHRONICLE. 



[March 9, 1912. 



of hnrk on the stakes. It is to bo feared that 

 many of these good friends of the fruit- grower 

 *r killed by spraying, and particularly by strong 

 inter washes. 



Methylated Spirit for Woolly Arms. 



In the autumn several young Apple trees were 

 badly infested with the w r oolly aphis, mis- 

 called "American blight." Nearly every shoot 

 on an affect <■» I tree was covered along almost its 



entire length. The pest was brushed with a 

 paintbrush dipped in neat methylated spirit. 



About 20 trees were ait- cted, and although they 

 were treated only once, all but two were quite 

 clean when they were gone over recently for win- 

 ter pruning. This show r s how thoroughly effec- 

 tive methylated spirit is when used neat. There 

 is nothing equal to it for penetrative capacity. It 

 sinks into the wool in which the insects are en- 

 shrouded with a mere touch of the wet brush, 

 and every one with which it comes in contact is 

 killed at once. The remedy is perfectly harm- 

 less to the trees. Frequently, the buds of budded 

 Apple stocks have been thoroughly wetted with 

 it, when the woolly aphis was found upon and 

 around them on taking off the raffia fibre used in 



budding, and no harm has been done to the buds, 

 as was proved by labelling some of them. 



Stages of Vegetation. 



Considering the unseasonable mildness of th 

 winter, it is remarkable that vegetation is not 

 even more advanced than it is. Gooseberries, 

 among fruit trees and bushes, are most strik- 

 ingly forward. Many buds had burst by 



February 21, and a week later this stage was 



common. At first I thought that the former 



date was early beyond precedent in my experi- 

 ence, but reference to records of past seasons 

 shows that this was not the case. In the very 

 early season of 1894, Gooseberry leaf was nearly 

 half out on February 8 ; in 1898, another very 

 early season, it was a quarter expanded on Feb- 

 ruary 20 ; and in 1908 the buds had burst by 

 February 19. In 1909 the same stage was fully 

 a month later than in 1908. In 1910 and 1911 

 the bursting was noticed on March 1, which may 

 be regarded as the normal period for my district. 

 Onlv once before in 18 vears has the Almond 



blossom been so early as it was this season. It 

 was fully expanded here on February 28. In 

 1898 the corresponding stage was reached on Feb- 

 ruary 22. The Buds of Black Currants are not un- 

 usually advanced. The fruit buds of early Apples, 

 Pears and Plums are forward, but not much more 

 so, I think, than they have been in some previous 

 seasons. This accords with the leafing of the Elder 

 and the Forsythia, which are among the earliest 

 leafers ; also with the flowering of the Snowdrop, 

 the Crocus, and the old double Daffodil, which 

 has been common in my garden in the last 10 days 

 of February in previous seasons, as well as in the 

 present one. It is too early to tell, however, 

 whether fruit blossoming will be dangerously 

 early or not. In many a year the danger has 

 seemed obvious at the end of February, and then 

 frosts have occurred to check further advance, so 

 that blossoming has not taken place before the 

 ordinary dates. If mild weather should be un- 

 broken for a fortnight, probably there will be 

 much premature blossoming; but a March with- 

 out many sharp touches of frost would be almost 

 beyond precedent. 



Promise of a Great Nut Season. 

 The show of blossom on Cob Nuts and Filberts 



Indeed, the prospects of most kinds of fruit are 

 trembling in the balance, as they always are at 

 this period of a forward season. 



Good Prices for Late Apples. 



Last month it was remarked that the keeping 

 of Apples till the middle of January had not 

 been very, if at all, profitable. But fruit 

 kept a month later made somewhat high prices, 

 good samples of Bram lev's Seedling and Newton 

 Wonder having made 7s. a bushel, while Cox's 

 Orange Pippin has been quoted up to 10s. per 

 half bushel. 



Spraying for " Big Bud. 



SOME FACTORS OF SOIL FERTILITY. 



Carbon-dioxide and soil-fertility. — There 

 are one or two points regarding the value 

 of carbon-dioxide to the plant, and bacterial 

 activity in the soil, arising out of recent work. 

 It is, of course, generally known that carbon- 

 dioxide is probably the chief solvent agent 

 excreted by the roots, that much is carried down 

 by rain, and that it is also produced by thi 

 rotting of organic matter in the soil. The ques 

 tion thus arises as to the value of adding still 

 further to these natural supplies by watering 

 with water saturated with carbon- dioxide. Pot 

 experiments have been tried by Mitscherlich with 

 various manures, but the results have not shown 

 that there is any advantage in using carbon- 

 dioxide water. 



Substances which are capable of producing 

 carbon-dioxide in the soil were also added with- 

 out result. It seems, in fact, that, under natural 

 conditions, the requisite amount is nearly always 

 present. The amount produced by the plant 

 varies not only with the species, but also in- 

 creases when the soil is naturally fertile ; the 

 enzyme in the root hairs, which is chiefly respon- 

 sible for the production of carbon-dioxide, is a 

 peroxydase. This is most active in neutral or 

 slightly alkaline solutions of soil water, while 



acidity and lack of aeration are inimical. 

 Calcium salts and phosphates are favourable t 



carbon-dioxide formation, whereas nitrates art 



not so, though better than ammonia salts. It will 



be remembered that most acid soils are wanting 

 The interest that has developed in the Avocado {n l{m ^ and when thig ig the cage the phosphoru 



Pear during the last year or two is remarkable. 



I am obliged to Mr. Pearson for the details of 

 his plan of spraying for the control of mite attack 

 on Black Currants (see p. 142). The number of 

 sprayings required is a serious objection to the 

 adoption of the plan on a large scale, and the 

 quantity of quassia is more than twice as much as 

 is required to kill the aphis or the Apple sucker, 

 together with a very liberal quantity of soft soap. 

 A South* t/i Grower. 



FOREIGN CORRESPONDENCE. 



THE AVOCADO PEAR IN CALIFORNIA. 



Californians seem to be awakening to the 



possibilities of such fruits as the Avocado Pear, 



the Mango, the Guavas, and the Cherimoya. 



While this fruit has been grown in California for 

 30 years, it had never been given any thought 

 as a commercial possibility until a few years ago. 

 A few horticulturists who foresaw the important 

 effect this fruit could have on the food 

 supply of this country, and who realized the de- 

 sirability of a wider cultivation of the plant, 

 awakened an interest in it through the columns 

 of the horticultural Press. Now the trees are 

 being propagated by the tens of thousands. One C. is a very suitable solvent. 



acid has an opportunity of combining with the 

 iron and aluminium bases to form compounds 

 which are not readily taken up by the plant. 

 With respect to methods of determining the 

 availability of phosphate in the soil, the usual 

 English procedure is to treat the soil with a 2 

 per cent, solution of citric acid for one to seven 

 days, according to the amount of shaking. 

 Wisconsin experiments state that N/5 nitric acid 



una 



per cent.) for five hours at 40 



firm alone, which grows tropical and sub-tropical 

 fruits exclusively, has at the present time over 

 50,000 seedling Avocados in the nursery, ready 

 for budding in the spring. 



The entire southern part of the State has been 

 searched over to find the choicest seedlings to 

 propagate from, for the nurserymen have decided 

 to start the industry by propagating the best 

 possible varieties. When it was found that 

 the seedlings which have fruited here were in- 

 ferior to many that could be obtained by going 

 to Mexico and Central America, where this fruit 

 has been grown for centuries in countless num- 

 bers, private enterprise at once sent down horti- 

 cultural explorers to obtain the choicest varieties 

 to be had in the highlands, where the climate 

 closely approximates that of Southern California, 

 thus making it practically certain that the varie- 

 ties .would be a success here. The Mexican Avo- 

 cados are probably as fine as any in the world, 



and are certainly found in as great a variety of 

 forms and under as widely differing climatic con- 

 ditions as anywhere. Those most desirable from 

 every point of view — hardiness, shipping quality, 

 form, flavour, and productiveness — w T ere secured, 

 and bud-wood sent to California for propagation. 

 From this start commercial orchards will soon 



-The uses of 

 soil have become 



is quite extraordinarily abundant. As for the be establisned - ^ is worthy of note that Cali- 



w — 



catkins, I have never before seen any approach 

 to their profusion. There are ten times as many 

 as are needed to pollinate the female blossoms. 



fornia is already producing Avocados during 10 

 months of the year, and it is expected that within 

 five years it will be possible to obtain ripe Avo- 



and although about half of them, or three-fourths cados in this State during every month. 



in some cases, were turned brown by the recent 

 frost, there is an abundance of sound ones left, 

 besides which the brown ones have some pollen 

 in them. It is not at all improbable that we 

 shall have frost to spoil all this fine promise, as 

 ■o often happens with the uncertain Nut crop. 



It is expected that a large demand for the fruit 

 can be built up in all parts of the country, when 

 it is marketed at such a price that it is within 

 the reach of all, and its qualities are more 

 widely recognised. F. W. Popenoe, Altadena, 

 California. ' 



Boric acid as a manure. 

 partial sterilisation of the 

 familiar from the Rothamsted and other ex- 

 periments, as also the commercial preservation 

 of milk, &c, by boric acid. Ideas from both 

 have been combined and boric acid has been used 

 as an indirect manure. It has been found that 

 one part in 100,000 of a nutrient solution is dis- 

 tinctly beneficial. When applied to soils at the 

 rate of l-50th of an ounce per square yard Maize 

 increased 50 per cent, and Turnips 32 per cent 

 Some other crops did not gain so much, but with 

 none was there a loss. The ash of the crops 

 taken from plots so treated did not show any 

 increase in the normal amount of boron com- 

 pounds present. The modification of the bac- 

 terial content was not stated, but we understand 

 that further experiments are in progress. ^j** n 

 we remember that boric acid at the rate of 6 lbs. 

 per acre increased a Turnip crop by one-third, 

 the economy of such a method, if successful on * 

 larger scale, is very apparent, considering tna 

 boric acid costs about 5d. or less per lb. 



Depth of cultivation— the bacteria of *iL 

 — An interesting experiment on the effect o 

 depth of cultivation on the activity of bacteria 

 is reported in Bulletin 161 of the Kansas State 

 Agricultural College. Plots were stirred to depth? 

 of 2, 4, 6, 8, 10, and 12 inches, and it was found 

 that the most fertile were, naturally, those stirred 

 to the greater depths ; though stirring to 8 and 

 10 inches produced in many cases better re 

 suits than stirring to a depth of _ 12 ^ches. 

 There was also a corresponding increase 

 the amount of ammonia and a decrease in ^ 

 rate of denitrification. As regards the distribo- 

 tion of the bacteria, most were found between 

 and 6 inches from the surface. More or J* 

 regular periods of increase and decrease « 

 also noted. /. W. Taylcur, Theale, Berks. 









