XIV 



IRISH GARDENING. 



up on trellis if necessary and benl down to allow 

 the house to pass over them. The inventor finds 

 thai for some crops e.g., spinach sven tine, 

 davs' forcing makes a very greal difference, and 

 by means of the movable house not only can a 

 succession of any pari icular crop be go1 . bul i-rops 

 ,an be so arranged on the plots thai directly one 

 crop is ready for marketing, the house is moved 

 on to the next. As many of the crops', such as 

 bulbs, asparagus, mint, &c, would remain in 

 the ground for several years, a man would require 

 comparatively little labour, and Mr. Pullen- 

 Burry claims that one man can easily work an 

 acre of land on this principle, while the theoretical 

 profits are large. Although such profits would 

 not always he obtained, t here is no doubl that the 

 profits should he good, as the crops would he 

 early on the market when prices were high. 

 Another advantage of the system is that such 

 flowers as double narcissi and peonies, which 

 cannol be forced if they are shifted, remain in 

 their beds ami are then readily forced. From 

 The -hm rmil of the Board of Agriculture. 



The Intensity of Light and its effects 

 on Vegetable Assimilation. 



In laboratory experiments on carbon assimila- 

 tion it has been demonstrated thai assimilation 

 is more active in direct sunshine than in diffuse 



daylight, and. by analogy, it has been assume. I 

 that the same held good for vegetation under 

 natural conditions. Of course under held con- 

 ditions, the plants exposed to diffused daylight 

 aie also expose. 1 to fa i' more humid conditions 

 generally, and the larger supply of water more 

 than counteracts the effect of the greater lighl 

 intensity. Bui given that the water supply was 

 always sufficient, what is the effed on vegetation 

 of lighl of high intensity ? In order to tesl this 

 poinl a crop of lucerne' was sel aside at Mrnil.ui 

 during the three summers. 1910, MM 1. and 1912. 

 Pari of it was given no special treatment, while 

 the other received 111 litres of water per square 

 metre every 7 days, -,.. that the soil never dried 

 out. The yields of dry matter per square metre 

 p.-r day were as follows : 



i nder natural 



III ..Hi- w atered 



1910 . . . 5.24 grams 10. 56 grams 



I'.Ml . . . 1.24 .. 7. mi 



L912 . . . 3.12 .. 9.42 



During the years L910 and L912 the sky was 



overcasl during the greater pari of the summer, 

 whilst 1911 was a season of brighl sunshine and 



drought. Tlie yields under natural conditions 



show the relative importance of lighl intensity 

 and water supply in plant growth, hut even when 

 the latter fact. ii' is eliminated by artificial water- 

 ing, tin- more intense lighl appears to have an 

 unfavourable effeel on the production of vegetable 

 mat t it. 



This apparently contradictory result obtained 



when a laboratory experiment is extended to 

 held condition- arises from the fact that in the 

 laboratory the plants are necessarily kepi in an 

 artificial atmosphere relatively richer in carbon 

 dioxide in order that it should he possible ii 

 detect variations in the percentage of that 

 caused by the process .-f carbon fixation •. whilst 



in the natural atmosphere the amount of carbon 



dioxide present is so small that the solar radia- 

 tions, he they diffused or direct, are alv 

 sullicieiit to make the besl use of the carbon 

 dioxide. In other words, carbon assimilation is 

 limited by the amount of carbon dioxide in the 

 air. and not by the intensity of the solar rays 

 Monthly Bulletin of Agricultural Intelligence 



Some New and Unusual Insect Attacks 

 on Fruit Trees and Bushes. 



By Professor l\ V. Theobald, M.A., F.E.S., 

 South-Eastern Agricultural College, Wye. 



Several interesting attacks of insects on fruit 

 trees and bushes have to be recorded for the 

 past year. 



Amongsl those of special interest is an apple 

 leaf sawfly (Lygseonematus moestus, Zaddach), 

 which has not previously been recorded as British, 



It is interesting to note here the change of host 

 plants by two insects namely, the beech 

 orchestes (Orchestes fagi), recorded as feeding on 

 apples in Devonshire, and the ash and willow 

 scale (Chionaspis salicis) attacking currants at 

 Woburn and Wye. 



Three well-known insects are also recorded for 

 the first time as attacking fruit in this country 

 namely, the garden chafer (-Phyllopertha borti- 

 cola), eat i ne apples : the V-moth (Halia wavaria), 

 on currants and gooseberries : and Pseudococcus 

 aceris, signorel . on apple t rees. 



A new capsid bug attack (a species of Atracto- 

 nomus) on apples in Suffolk and Hereford is also 

 worthy of not ice. The nu m her of Capsidse attack- 

 ing apples is gradually increasing. It is difficull 

 to distinguish their damage to the fruit from 

 damage by thrips, and to the leaves from damage 

 by collembola. Catching the insects only will 

 decide which is t he culprit . 



The Apple I. mi Sawfly.- The larvaeof this sawfly 

 (Lygseonematus moestus, Zaddach) have been 

 senl to me from Week Green, near Petersfield 

 (Hamphsire), and from Mortimer (Berkshire). 

 where they were feeding on apple foliage. I 

 found a small colony also near Wye on a 

 Worcester Pearmain in 1907, hut did not rear 

 t hem. 



The larvae were first sent to me from Week 

 (M.en by .Mr. T. E. Crompton on June 6th, 191 1 

 Me found them in two orchards 1 ! miles apart, 

 and on June H'th he sent another supply, these 



being considerably smaller than those lirst 

 received. The firsl pupated on June 1 3th, and 



the last on .Inly 22nd. Some of these pupated iii 

 the soil, ot hers on the soil, and some amongst t he 



foliage. Those in and on the soil covered the 

 yellowish silk of their cocoons with line particles 

 of earth : those on the foliage had thick cocoons 

 of pale dull yellowish to brownish silk. The 

 adults hatched out from April 20th to Mav 5th, 

 I ill 2. 



The ciiIoiin from Mortimer, twenty in number, 

 WHS found on a " mother" apple, and was sent 

 to me by Mr. (i. D. Lake on .lime I Ith. 1!»I2. 

 All pupated amongst the foliage, making similar 

 cocoons to those which pupated amongsl the 



leaves in the previous >ear. Others were found 



at Week Green in L912. 



The larva; are very marked in appearance and 

 feed freely on the leaves, mainly eating them 



