92 



IRISH GARDENING 



the writer has completely failed to get alatie of 

 malifolnje to reproduce on riuntayv. Un the other 

 hand they have done so on the Guelder Ross 

 {Vihiinunn opidus). The only plant louse found 

 conunonly on plantains in Britain is the green 

 Aphis plantufjinis of Kaltenbach, so often seen on 

 the roots, leaves and flower stalks; it is a specie.; 

 of very similar structural form but is undoul)t- 

 edly distinct. The writer has failed repeatedly to 

 cultivate this speciei on the Apple. It is a well- 

 known and " attended " species. 



Alate females of irmlifolne commence to return 

 to the Apples late in September, but the majority 

 do so in October and even on into November. 

 These returning migrants jiroduce the apterous 

 egg-laying fenuiles and, so far as the writer has 

 traced, some alate males; but some of the latter 

 appear later, and it is probably nornuil that the 

 alate nudes fly back from some host plant to the 

 Apples, at about which tiuie the oviparous females 

 are mature. On two occasions the writer has 

 found this insect on the Apple trees right through 

 the year. 



The Green Apple Aphis {Aphis pnmi). which 

 mainly lives on the top shoots and is found also 

 densely packed beneath the leaves or in scattered 

 group-S may curl the foliage, but never to the 

 same extent as does the Blue Bug. Like the 

 latter it winters in the egg stage on the Apple and 

 spends its whole life normally on the Apple and 

 Pear. The writer, however, has recently found it 

 in several localities on thistles {Cor(htiis). both as 

 alatae and apterae. In two instances alatie taken 

 from tlie apple liave produced large colonies when 

 transferred to species of Carduus which have been 

 covered with muslin. This is what may be called 

 an " erratic migration." It may be necessary for 

 the continuity of the species, yet it is neverthe- 

 less very unusual; just as the migration of the 

 Woolly Aphis to the elm appear? to be in this 

 and some other countries. In any case, the aphis 

 returns to the Apple and Pear in autmnn, and 

 the eggs laid on them hatch out from mid-A])iil 

 to early May. It increases very slowly at first, 

 but later in Jmie and July it frequently does so 

 very rapidly, especially on young stock. Winged 

 feuiales may l)e found froiu the end of June to 

 well into August, and these migrate to other 

 Apple and Pear trees, and, it seems, sometiuu*; 

 to thistles. Undoubtedly this species occurs 

 nornudly all the year on the Apple and Pear, 

 both in Great Britain and America. In October 

 the sexual forms appear; the males, inilike thon; 

 of the other two species dealt with here, are wing- 

 less. The ovii)arous fenudes, when pregnant, 

 swarm on to the shoots and deposit their eggs. 

 The ova are pallid at first, but soon becouie shiny 

 black; they are laid in masses all over the young 

 wof)d. 



The Oat-Apple Aphis {Sijilioi-oii/iir a nun) -.xi-n 

 passes tlie winter on the A))i)lc in the egg stage, 

 and sometimes on the Pear. The eggs, wliich 

 are mostly laid singly, hatch out in April, and 

 the young are to be found on the first leaves. The 

 wingle.s, females coming from the larvse continue 

 to increase throughout May, and by the end of the 

 month alate females appear and fly off luitil mid- 

 June to corn, especially to cultivated and wild 

 oats, but also to barley, wlieat and griv^ses. By 

 October, the corn feeders give rise to winged 

 fenudes, which fly back to the Apple and Pear 

 and produce yoimg, which become egg-laying 

 females, and later on alate males return and 

 fertilise them. The pregnant females then lay 

 eggs on the trees, often as late as November. 



I'lrccidiuii mill Trinttncni. — The matter of 

 Ijrevention is very difficult, if not impossible, for 

 the various host-plants of the Aphideis cannot be 

 removed. This nuiy be specially noticed in the 

 case of Alibis inalifoliae and Siphocuryne avenie, 

 for it cannot be hoped to destroy all the count- 

 less plantains or whatever other plants they 

 attack, and certainly not the cereals and wild 

 grasses. 



Reliance nnist consequently be placed on 

 treatmi'Ut. This nuiy be carried out by (1) timely 

 spraying, or (2) dusting or dry-spraying the 

 attacked trc(>s. If either of these methods be 

 adopted in the autunm, so as to kill the exposed 

 oviparou.3 fenudes and thus prevent egg-laying, it 

 nuiy prove a preventive in the true sense, for 

 there can be no blight in the following year. The 

 treatment, or what may be called the preventive 

 treatment in the autumn, nuist be very thorough, 

 a? a few apterous egg-laying fenuiles left nuiy 

 deposit eggs, and in the spring the young from 

 them may produce a vast progeny. 



/\ny spray used against theise pests must be 

 a])i)lied heavily, really as a " wash," and not a 

 fine mist. Th(> spray should be applied, when 

 possible, after rain. If rain comes after the 

 spraying so much the better, an the moisture 

 carries the wash into all curled leaves and 

 crevices. On the other hand a powder or dust- 

 S7)ray should be applied in dry weather. 



In the case of the leaf-curling Apple Aphis (.4. 

 itiiilifdJin) it is almost useless to spray when the 

 leaf-curling has definitely started, as even with 

 such very peru'trative washes as nicotine and 

 pyridine a large number of the insects are not 

 touched and subsequent iswarms may occur. 

 finless spraying for the " Blue Bug " is done when 

 the insects are (unte young, that is, before the 

 so-called " Mothei- Queens " have started to curl 

 the young leaves, it i- d()ui)tful if spring spraying 

 is worth the cost. 



With the more open-feeding species, such as 

 Apliis jioini and Siphocorync nvenfr it is very 

 different, for any good aphis w'ash will kill them 

 readily. Unfortunately they are not the most 

 pernicious form?. It seems to the writer, from 

 various experiments carried out during the last 

 15 years, that autumnal spraying is of special 

 value in this particular ca-se. Spraying to jkill 

 the egg-laying forms of all three species, which 

 might be called (|ua>?i-prevention,— appears tcr be 

 the. most satisfactory method of control. When 

 the Apples and Pears are harvested, fruit growers 

 are not anxious to spray again, but the writer 

 feels convinced that if they wish to do away with 

 the often serious damage cauied by the leaf curl- 

 ing aphis, they should do so. 



Another method of prevention has been found 

 most satisfactory for the " Blue Bug," namely 

 spraying with lime and salt. This should be done 

 when the l)ud.; are swelling and just beginning to 

 burst. The young hatched aphides are killed, and 

 many that uuiy hatch later are ])revented from 

 entering the opening buds. Some authorities ad- 

 vise lime wash alone, but the writer has found 

 that even a small (|uantity of salt has a most 

 beneficient effect. The wash is nuide of 1 to 

 H cwt. of lime; 5 lb. of salt; 1(K» gallons of 

 water. 



The lime has to be slowly slaked and run 

 through coarse sacking into the water in which 

 the salt has l)een dissolved. With siutable 

 sprayers thi-; thick wash can be put on with ease, 

 l)ut readily-cleaned nozzles should be used. The 

 best white' lime, .-md as pure as possible, iinist be 



