The leaf blister mite (Eriophyes pyri Pagenstecher)


Material Information

The leaf blister mite (Eriophyes pyri Pagenstecher)
Physical Description:
Quaintance, A. L ( Altus Lacy ), 1870-1958
Government Printing Office ( Washington )
Publication Date:

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Resource Identifier:
aleph - 29683391
oclc - 27970992
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Full Text

U. S. [).PARTMIN.T ())1 .\(;RKI(I
BUREAU 'F E 'TiiM .L;Y 'C RF.i *L K N,
L 0 )I OW \HD [ n..,l. i ,,, t ),,-l ,I 1 ut-4u


A. I. (,I.INTAN( 1.:.
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J f!.'1{1'U OF :'l\T7)1I .ni);Y.

L. 0. IHOWARD, [.lilol,,,.1!.,.1' ,nlI ("iif f of Bill q .
C. L. itII \ii. Enitomnologist and _A' i,#!7 'i, i f 1 .1 ljiii, ',if C'hirf.
ItR. S. CLIFTON, Ex'e( iilir' .kil.,iintl.
W. F. TASTET, 1- hi,'f C" rl:'.

F. H. (imi ii \Ni \. in charge of truck crop omI vtol I 'I 10r',lii't in.'-'I in, t11 qillij',m.
A. D. Ii'ii.:i'.>. in i ,iin' of forest inswct ii,'< liquliin.-.
W D). Hi N ii -. in charge of ,,n'ilii I1 fn lit i l ,p if#.,# I i t''lqtli.i '
F. M. \WV ir:ii[. in charge ,,f cereal anld f,,rytii, in',.t inc(%liiqitiflv%..
A. L. QUAINTANCE, in charge of fi 'ilt, ,iv f!it nl l.'.< if i1t1 vliilimnx.
E. F. PIIIILLIPS, in charge ',f bec .ultlurc.
D. M. Ro(;ERS, in I bIn il' of preventing xpri adl rof mitt.'. fiethl irorlk.
ROLLA P. CURRIE, in 'Chliim!l, of editorial M ,,L.
MIAPBEL C-t 'ORPI. iln v hiiri of library.


A. L. QI .\INI \N :. iii if 1ivht 'u .

FIi[i[ J.OHNSON, S. W. 'USI F, P. R. JONES, I". E. BROOK.S.A. A I. H1M MAR. IE:. 'W.
SCOTT, I. L. NOUGARET, II. A. C('I IIM.NAN..L. L. S( 01. .1. I.. A. '. l1,%KEHU,
W. M. DAVIDSON, E. B. I..KSI.L, W. 1B. WOOD. E. II. S.iD.LER. 1". I.. S[UIAN-
TON, r'iilowioiiinlii'il assistants.
J. F. ZIMMER, N. S. ABBOTT, W. H. SILL, v iitoioildopiti'l ,ii'triintv. .'iiipl!e-'d in
en forecmnent of insecticide act, 1910.

lmnn>d June I.I. 1iila
United States D)cpi rtment of Agriculture,
L 0 HOWARD. Enim, .1..,.t and Chif of BurCau.

( ','i/),i 11, ;fri l' ienI t l-herr)

l'>V A. L. Qt M.,A i'K.
in hmrr., tf jIi i, l,,,,i^ Frui lnmp't I, "li,.ii,,,, .


Leaf hbii-t.rr mile, are :1111ii i I. the smallest of animal formi-s which
attack hoorticinh 1ural crops. Tri"-i, minute 'r,:,iliir,-. only one one-
hundred-amnl-liftluth if an inch in hit.ll,_i. are invisille to the un-
aided eye. a;In(I[ :, -en under a :'rI hand lens appear as the merest
-peck. Altlhomgli the mites theiselvet s are probably unfamiliar to
most orchirdi-t-.. their work is well known, to pear growers and
npple gnrm r.'., in tle reddish or g\i, I'li-i pimples or bhlisterlike spots
to Iw noted in iarl -'ipiiil on tie \ ',iil'- f',lii--,, of these
Later the-e bli-ter- become brown and dead, spt:illi, and I Itl-, iii,
the leaves, the injiiry ,e- i-.nllinir, that due to leaf--p,1t fiimii or frii
sprayvs, with wIich injuiir' in fact, the work of this- mite is fr1.i.iilly
confsed. When the creatures are abundant thl f,,li.i,. may be
iilmio-.t covered with the blisters or brown -l,>,~. and the usefihlies of
the leave., to the tree is thus ._rr:itly impaired. Fli.iL., severely
injured \\will fall premaniturely, retarii,_ the ,v.lip ,.iidt ,it tile t' fit
i nild in extrent .a,-', munch of the rp will fall to the L,''iiil. (See
fig. 1.)
rThe leaf hli-ter miite is not an insect, but ',,,'ii .- to that class- of
inimal-. conmtiniiiii.- the spiders, scorpions, daddy l,,'r.:lc.-. etc., and
to thIe order .\Acarina. represiented by .sch well-known forms as the
scab nite of lieep. the cattle tick, and the red spider. It- f.iinilk,
lie Erioph.yixl, (Phytoptidwe), contains numerous -'.'i0-. all of
vhiih are plhint feelr. atl 1 1kiii,_ i'iwi ipilly il,' Iiml- and leaves.
Several member- -f the family are of much economic iii,,'rtance.
Erhiptqhyit. ,';f.. Lantoi-. infests vifii,.[-:, varieties ,'f ,_,rI ,",-. in por-



tions of Europeu andI in California, producing the so-called erinose"
of the vine. Eriopliyex mpudi Nalepa (=E. itfl-Ct-cimtena Walsh)
is thlie cause of the' nail-like galls sometimes found on the leaves of
plmin. ( T,/p/lodrum'o,,s) P'iyllo, optcs oli'orTiis. A-lmead infests the
fruit and foliage of the orange, producing a russeted condition.
PIqIlovo, tt.s c;rniut!f Bank- feeds upon the upper surface of the
ltavi-. of thlie peachli. ') injuring them ai to give the foliage a silvery
sheen. I/, tllocol:fcs scldvrldccliclall Nalepa occurs on the foliage of
the ap ple. and in Montana very important injuries have been at-
tributed to it.

Ii'. 1 .\p|ple Ivaar .. injured I'y liv loafr hih-,-r mil, iErivlphij's py. i). tOriginal.)
Tie mite is not native to the United States and was probably in-
troCdli(,, at an early period, presumably from Europe on nursery
.tock. Ijtlds. or scions. It was fir.t recorded in the United States by
Twnerld (;lover, in 1872, and s-ince that date has made its appear-
aite il tire principal pear-growing regions of thlie United States and
(.'Ia (,da. It i- known to occur in portions of Europe, in England,
]ii--]i :m. ;id Ta-man I ia. and i, probably present in other fruit-growing
r..ii,- if tire world, being at. thie present time a truly cosmopolitan
pj' t.




The Illit 's- pas the win Iter Ion tlb ,-,I und fr the b -III ~ ii-I. Id
attark Ithe leaves as -oon as these lI..,ii to ,pii-h otI in tli -]i,,ii
111hey l.,r,- .i l holes 'ri, tii(he und rsi, h, t( the interior ,f the J.., f.

where t hi deposit their '.'-. and wih their It''i"Y upon thIt
lenit Ir ,i'lls if thIe leaf sulsItance. Their a,1 tiv iti s within tle leaf
tis.i \ery viiikly I reult in theil deIvohmtenlt of -,.1i. or 1wel lii ,-.
Tle.e. aret at first -rniill, pimpIple-like erui tIn. ei lwcially e, ident on
the iilp.r .i.l rf:i, of ,iiri lI.:iv' s whitit I in color onl the apple,
but uiiiaIllv with a reddish liin_'
(on the pein r. The -p,,{, so,(, i
increai-e in -ize, th, lri-.' lh-
coniilli, aI, much as ,Ie-IiLtll, uf
an in leave, t hIe spots, :i- a rule, be- h e
comlle re,. often lrilliai ntly col- I,. 2- .ar f all,. in vrowUiion, of laf
oreld as licv -row, whereas on itir irit o,. niening tf iall ess
1.1 o rf liti* 11. nirinal structure of laaf.
apple (hi, ret li-hi ',Ilorinir is ab- of tri s ,,raar sf
,~ VAttor S~orau,1r
sent or faint. On the iuiildride
of the leaf the iall,'- are whitish and bliterlike, not ,il',criil 'r much
from liw general color of the leaf surface. Later they turn brownish
or black, due to the d,,atl of the injured leaf .,l-. lose much of their
thieknes,. :and some nmiv become omwhat shrunken. Figure 2 illus-
trales a gall on pear leaf as seen in cross-section, lie normal structure
being .-hiwn at ,..' o is the oli, Ininir, to tile interior of thl :i lt and
designate- et.g.- of the mite. A cro s-section [If one of the ,rieil-np
galls is shown in fig rre 3.

PIG. of leaf, showing structure of L-i, of tliter mite In autumn: g, Gail o,
opening of gall. (After to 'n ltk.4

On pear. the .'.Ld11-l occur 1more al,',ni each side ,f the mnidrib of tile
leaf and on apple at the base of. Mland ,li'ng the 111:,uiri 'if the leaf.
When nunimeroii,. however, the spots will iii'.r,,. tit1,tlier, frni i,.n
large patche,- or bands if variable size. ,'fi1,,, ill',1\ ii.. most ,i, the
leaf. When thus ailiiiii lint the leaves may Ibcome more or less rup-
tured and wrinkle., and in the case of the : tialp the nmriT'in- 111:1 nv
curl iup. sho,\\inm- the underside. Leaves- badly infested are likely
to fall preinaturl. re-i, ti ini, also in the ilropilit,.. of til' fruit fr,,iii
cluter within worst inijilrl foli;i,'V. Tlih fiIii and frulit-stems of
both apple and pear are also attacked, the li,..l-t-colored pimples

'11 11 I.I \1 1 1 I.IS l I 1: M% i ll .


occurring mostly around the calyx end of the fruit and resulting in
no material injury. Tii. injury to the friit-teni:- is noticeable as
irre ',,rj.I c,.. and when severe may cauie some of the fruit
to fall, although loss froln this source, even in worst infested orchards,
will not be gn'.:t.

Pear and apple are the more common food plants of the blister
mite, though other plants are attacked. Dr. Nalepa records this
species from foliage on the white beamn tree (Soifs aria Crantz).
the European mountain ash (Sorbus ,a,,'.paria L.). the wild service
tree (Sorbus torminalis Crantz), the servicee berry (.Amelarwchier
rWlqaris Monch.), and the common cotoneaster (('otonreaqter vulgaris
According to Parrott the mites have been found on over 250 vari-
eties of apple-,. injury being severe on some well-known commercial
sorts, as Ben Davis. King, Baldwin, Rhode Ishland Greening, and at
the agricultural experiment station at Geneva, N. Y., the Williams
Favorite was noted to be especially subject to attack, the trees having
been prematurely defoliated for two successive seasons.


The general appearance of the blister mite is shown in figure 4
in dorsal and ventral views. The mite is mi ro-copic in size, measuring
on the average about one one-hundred-and-fiftieth inch in length,
whitish in color, a few individuals pinkish. The abdomen slopes
gradually toward the posterior end and is numerously ringed. There
are only two pairs of legs. and these and the body bear selte, which
from their character and location are of importance in the deter-
mination of species in this group, as are also the number and charac-
ter of rings on the abdomen. The young, except in size. bear a gen-
eral likeness to the adults, and the eggs. though proportionately
large as compared in size with the parent, are only 46 microns
through the greater diameter. These are whitish, translucent, with
rounded ends, and are deposited in the interior of the galls (see fig. 2).
The resulting larvae feed upon the cellular leaf ,substance, working
out in various directions. though they are not especially active.
The mites are to be found on the foliage from their appearance
in -pring until fall, and several generations are evidently produced
in a season. Hibernation occurs under the bud scales, the mites often
,',ijgregZ:utini in colonies of 50 or more. They become active in the
spring often before the buds burst, congregating around the base of
bud scales, where they feed. many molting at this time. With the
bursting of the buds and the pushing out of the tender leaves, these
are attacked and the characteristic blisterlike spots soon develop.

Not\\ itti'.l i ii! u iniii i uillte i.t ,f lthr- ii ature -. tll hey f Iill I v
iln o., 'l-l~ hriil-h, i~iiiinl,,,i-. asr o1,\rvr I PIl. I'.irr 4li ill Ne\w Y 1o1rk
N aWliilr. t< to iittac ,f i iii h M finn P iiilltl) which hoe 'lihikI
iiiillri illyv iisd sis h in rl ,il IiL tlhuir t iliIuI, .
]%IB TIIuDI O)F riitN'rlll,.
h'lec leaf lici-,lr mite will vichl ito tlli, ,i lI, tri: tiiieinct with l ero-
t'LIIl tiliiil|-i 'i. miscible ,i1.. or Iilint'-uiillhuiir litie. Th' llusM. of
', 14

/A \T f

/ ^ /i'^

/I I

-thoe -r:-. as for the .n ose scale, should also protect orchards
frlu important injury from tic I e mites IheI it is nI cesVry toI
spray for lthe mites ilnIc. and in cases of severe iiirl-i:tiii,., as hlas
been naiT in 1;i])[>I orchards in NW," York Si:iic. two Ir'':iliiciilt-I
have been reomMended liv Parrott, sing -1i :1i1i 1:1 r il kerosene elnmil-
sion diluted with 1 parts ,f water. One application s houl I( e J( I i-I
in late fall as soon as most of the leaves have f.1 lliii and another the
tlI HWin .l irin._ 1,. lnfr the trees put out f i '..r,. If both the fall
:iid ring applications are not jIr;,'ti':,lilh. the pr. fIri. should be

1I'1 1. I.I \% I'1.1- I 1 : M II1E.

I .- .4

6 THE LEAF BLISTER 1 3 1262 09216 5959

given to fall treatment. At this time many of the mites have notyet.H
gone to the buid ,scale-. bIt occur in the pubescence of the young :
wood iand are henve more easily killed. I
Lime-sulphur waslhes are excellent treatments for these mites avA .|
their viployi ,ent is perhaps preferable as avoiding danger of injury
to fruit buds lby thle oil sprays. If a lime-sulphur wash is employed,
it should be applied it1 great thoroughness, completely coating the
tree so that when -praying is finished thie tree will appear as if
whitewashed. ThIe liomien;ide wash. according to the old formula," ,
lime '20 piind,.-. sulphur 1 .) pounds. and water to make 50 gallons,
will be quite effective; tr the Ihomemade or commercial concentrate "
miay be used. The former niay he made according to the formula,
lime 50 poinds. iiIu lphur 100l poinld:, ;ind water to make 50 gallons.
When thus prepared t lie concent rate .iould be used at the rate of one
part to 9 or 10 parts of water. Applications of these washes may
also be made in tihe fi';ll a- de-cribed for kerosene emulsion and if*
the l-priir,. and if onlly one treatment is to lie given the spring appli-.
cation is preferable. :- it take- the place of the first application of, '
a fhi,,_i,-ide for apple '-cail). Wliien the mite i, quite trolIblesome both ,.
fall and -pring treatments would in,,ire its control more quickly and J
,.,, "y
On the pear the nmite: may be kept reduced to an important extent .
simply by searching ot i, tIe siprinu" branches bearing worst infested 4
leaves, pruiii tl,,'.-e ot" aid hiurning them. or sprays may be em- "'
p)loyed exactly as indlicate foir tle appl)le, if this is considered
necessary. i!
Except in cas., ,,f -eriois infe.-tation special spraying for the A
Ulster mite will not lie eceu;,'ar\. As to whether or not it is advisa-
ble to spray, the ,ircha rli-it- will have to decide after determiningas
exactly as is poi --ilhlr' tlie ;mon1t oif injury I).ing done by the mites,
and care should I,( taikein not to, confound with it.- injury that which
has resulted front fitngicrilal oIr laris-green sprays, and from leaf-
spot diseases.
SeC r(/ ,f I I/',ff. til '.
WASIINGTON, I). C., .\ i,;1 iP. 191.?.

.D )iTIONA l CI' PIES oi iis, pubLieaClion
E n .t y Ie ircir-id from the St rI'ERINTUc -
E NT "rr ['aOcMENTN D uv. rnnt n I'nrithing
Office, Wa-hinvion. D C.. at 5 cnts per copy