xt7dbr8mf45p https://exploreuk.uky.edu/dips/xt7dbr8mf45p/data/mets.xml   Kentucky Agricultural Experiment Station. 1902 journals kaes_bulletins_103 English Lexington, Ky. : The Station, 1885- Contact the Special Collections Research Center for information regarding rights and use of this collection. Kentucky Agricultural Experiment Station Bulletin n.103. text Bulletin n.103. 1902 2014 true xt7dbr8mf45p section xt7dbr8mf45p KENTUCKY I J   l
  I I I
—  Aqncultural Expanmant Statmn K
V- \ OF TVHE ‘,  
  State College of Kentucky.  
  BULLETIN N0. IO3.  
  HKCW  
  HESSIAN FLY EXPERIIVIENTS.  
l E  
  LEXINGTON, KENTUCKY. .
vt; l December, |902.
  229
1 l
 "       ,,  {... -  L.  L _  

 . - " ` C i i
Q A —‘ A i
i KENTUCKY
 A . · I I I
4% , Agricultural Expcmmcnt Station.
  . Bonne 0r= cowrnot. `
 ‘ GEO. B. KINKEAD, Lexington, Ky.  ,
( D. F. FRAZEE, Lexington, Ky.  i
  R. C. STOLL, Lexington, Kv.  *
. Q \V. C. BELL, Harrodsburg, Ky.  ~
  .I. K. PATTERSON, President of the College.
i   M. A. SCOVELL, Director, Secretary.
  s·rATi0N 0r=r=icEns. ,
i M. A. SCOVELL, Director and Chemist.
I A. M. PETER, Chemist.
v_ H. E CURTIS, Chemist, Fertilizers.
L H. GARMAN, Entomologist and Botanist.
é J. N. HARPER, Agriculturist.
B * \V. H. SCHERFFIUS, Chemist.
, R. M. ALLEN, Secretary, Food Division.
  i .l. D. TURNER, Secretary to the Director.
Q — J. O. LABACH, Chemist, Food Division.
` GEO. ROBERTS, Ass’t Chemist. _
` ` MISS M. L. DIDLAKE, Ass’t to Entomologist and Botanist.
·   D. AVERITT, Ass’t Chemist.
` K D. W. MAY, Animal Husbandumn.
O. M. SHEDD, Ass’t lfhemist.
. E. P. TAYLOR, Ass’t to Entomologist and Botnnist.
Address of the Station—LEXINGTON, KY.  
  —  
Y? Morice.  
Q g The Bulletins of the Station will he mailed free to anycitizen of  
Kentucky who sends his name and address to the Station for
that purpose.
` Corresp<»ndents will please notify tl1e Director of changes in
their postollice address, or of any failure to receive the bulletins. ,
' Annunss: ‘
· . i{1·;x1·i·¤·uv A(ll{I(`(ZL'l`l'R.\ 1. l';X[’l·]RI).[l·IN'l` Srryriox,  
— Licxixwwrox, KV.
230
, l

 l s
  I
t
2
Fi
a
  Bulletin N0. IOS. sr
l ` .
V H—  K
I HESSIAN FLY EXPERIMENTS.  
. ` "E
‘ BY H. Gaiman, Exrrosionocisr AND Bommsr. if `
e
It is now possible to complete the report on experiments ji
4 made during 1901-1902 with reference to Hessian fly injury in
its relation to the time of planting wheat. Statements con-
, cerning the benefit resulting from early planting have hitherto
  been based very largely or entirely on the results of the general i
  practice of farmers. Wheat growers themselves sometimes
JY contradict the assertion that late planting is a means of avoid- S
ing injury, basing their opinion on isolated cases of good crops ‘
having been obtained from very early-sown seed. Such crops
are undoubtedly sometimes obtained, but if we knew all the
. circumstances an explanation could, in many of the cases, be V» J
i given entirely consistent with the common opinion that late  
T planting is the better practice. The following record continues j ·
and completes the partial report published in Bulletin 96. gf V
Eight plots of Hungarian wheat were planted in the fall  
of 1901, one week apart, on the following dates: September llrii
26, October 3, 10, 17, 24, 31, November 7, 14. The plots occu- .   _
pied one twenty-second of an acre of ground each. The land   V
. was in barley in the spring of 1901, and was already infested  
with Hessian tiy. \Vhile a primary object of the experiments i
. was to ascertain the time at which wheat might be planted so
  as to escape the fly, it was hoped that they might also throw
  some light on the question as to how late wheat maybe planted
é and yet escape injury from freezing—a question that is so in-
 
l
  V
7 V I I `V T W , ., .

 . T" ’ i l   l
  , j 232 Bulletin N0. 103.  
  . j timately bound up with the former that it must be considered  
i t V i in any effort to get facts that will serve as a basis for recom-  
  ` mendations as to practice. _ 
 _` w Effect of the Winter on the Plantings.  
 ’ Wheat planted in Kentucky in the fall of 1901 did not  i
  _ give as good a crop as usual. Some farmers attributed this yl
  l to late planting and bad winter weather—especially to a heavy  
  sleet storm that occurred in January——while others think: the  {
‘g_ flyttook it, notwithstanding the lateness with which most of [
  it was planted. But if the winter was the chief cause of the
E general failure, our later plantings should have suffered most,
whereas they suffered no more, as far as was visible, than the
‘ others. Furthermore, the late plantings were not injured at
lj- allin the fall by the ily. From observations made on these _
  plots and others on the Experiment Farm, as well as on
  wheat growing on farms in the vicinity, it is plain that the gen-
  eral failure was largely the result of bad weather at the time
  T of planting. The month of October was very dry, the rainfall i_
il beingljwell below the average for the month. Only two fully _ 
‘ ‘ cloudy days were recorded by the local weather station for the  
' T ‘ month. The variety plantings on the Farm have always done
. well whenever wheat is good in this part of the State, but in
{ 1901 came the nearest failing they have ever done. The seed
i J lay for a long time in the ground, owing to drought; then came
  _ a beating rain, leaving a crust on the surface, through which the
  plants that developed emerged with difficulty and but tardily.  
i. Such as pushed through grew very well afterward and were not  
, i harmed perceptibly by winter weather. ln this case, again,  
» F the ily had nothing to do with the failure in the fall and win-
ter, for the seed was planted after most of the adult flies had
— disappeared. Considering, therefore, facts of all sorts that
came under my observation, it was concluded that failure to
' secure a good crop in the spring of 1902 was due more to con- __
' ditions at the time of planting than either tothe winter weather i
or to injury by {ly.
Relative Condition of the Plantings.
During the fall there was a wide difference between the wheat
l 7 e

 f il
l
‘ Hessian Fly Experiments. 233   _
T of our different plantings, due in part to the work of the fly A]
and partly to the conditions of weather and soil at the time of,
and immediately following, the planting of the seed. g
_ Of course, in general, the early-sown wheat grew ahead of
  the rest, but earliness of planting was proved not to be the
  only factor in furthering the growth of the young plants.
* Even though the soil might be very dry, the wheat came  
{ up promptly and did well afterward if rain followed the plant-  
  ing. But if no rain followed, the seed lay in the soil longer x °-.
  without germinating; and, if the drought was long-continued, _   .
 _ the stand of plants was likely to be poor. Similarly, if the V   if
  soil was very wet when the seed was sown, the stand was less  
 Z perfect than if the planting was done when the soil was in bet- gi.
i ter condition. The result was that some of the plots sown `J  
  rather late were better than others sown earlier, in cases Where   ‘‘''
  neither were affected by the fly. I i
{ After the three last plantings (on October 31 and Novem-
5 ber 7 and 14) the weather was not suitable for growth. On
  October 31 the average temperature was 62°F., but sank to .
1 850 on the following day. On the 7th of November the mean
 » temperature was -160, and on the 14th it was 380 . The aver- ;
A age for the month was -10.2"F. The wheat in these three later ·
» plots was not visible as late as the 20th of November, but sub-
2 sequently the tips of some of the plants could be discerned
along tl1e drilled rows. In the spring, to my surprise, these 4 V
two latest plots showed a very good stand of plants, though  
  they remained somewhat behind the others, and were harvested A.
eleven days after the three earliest. The planting of October  
31 never did show a good stand of plants.  
As showing the condition of the plantings in the spring,  
‘ the following is taken from notes made May 12, 1902: . gy i
Planting of September 26~—Average height about 12 inches;    
· stand not as good as in thc next. —  
Planting of October 3—Average height 18 inches; better it
~ than the preceding; tallest of all the plantings.
Planting of October 10—Avcrage height 16 inches; good,
Q though not quite as tall as the planting of October 3.
  Planting of October 17-—Average height 12 inches; not
t
  I
ih l
'   -»   .... -. ..       .  .-  

 ‘  . 234 Bulletin N0. 103.  
  V quite as tall as planting of October 10, but good; one row  G
a 1 wanting, owing to failure of the drill.  
Y  Planting of October 24—Average height 12 inches; good,  
 _ ' but not quite equal to the planting of October 17. l
  Planting of October 31—Average height 10 inches; plants  
scattering and small ; the poorest stand of all. ` 4
 ` = Planting of November 7—Average height 10 inches; stand_  
  good, considering lateness.  
  lg Planting of November 14—Average height 9 inches ; quite `
`   uniform ; a rather better stand than in preceding planting.
  The differences in the heights of the plantings continued
l well toward harvest time, as the notes following, made May
§ 31, show:
  September 26—Scattering; headed out, but uneven in
  height; 25 inches high.
i* October 3—Fully headed out; even ; 36 inches high.
* October 10-——Headed out; even ; 36 inches high.
i S October 17—Headed out; even ; 32 inches high.
li October 2—l—Mostly headed out; uneven; 26 inches high. t i
' October 31—Scattering; uneven; some heads; 18 inches ,
· high.
November 7—Heading out; even; 24 inches high.
= November ]—l—Heading out ; even; 26 inches high. `
V VVhen some of the plantings were nearly ready to harvest  
_ the following notes were made (June 10). Contrary to my ex-  
  pectation they show not only that the late plantings were  
  slower than the others in ripening, but that the earliest of all  
, V (that of September 26) was later than October plantings. This  
· l is to be attributed to the fact that in the September planting l
some stalks were killed outright by the tly, and others pushed
· up to take their places, thus making the growth uneven and in g
general later than in plots where less injury of this sort was I
' done: {
September 26—Thin and not ripening. l
October 3—Very good ; heads becoming yellow.
October 10—Perhaps the best; maturing.
October 1T—About like planting of October 3. `
  f ’

 lt
i Hessian Fly Experiments. 235   V
. October 24-Not as good as preceding. 4
· October 31—Thin and not good.
November 7-Fair; not ripening.
3 November 14-One of the best; not ripening.
,  Yield and Quality of Grain.
  While the yield was not large for any of the plots, the \?
, relative yields are perhaps as significant as they would have  
  been if they had been greater._ The three earliest plots (of V  
  September 26, October 3 and October 10) were harvested June   V
  26. The two next (October 17 and October 24) were cut July 2. 7  
if The three latest (October 31, November 7 and November 14)  
f were cut July 7. All of the wheat was threshed July 10.  
i Planting of September 26-16 pounds. i  
r Planting of October 3-40 pounds.  
  Planting of October 10-28 pounds.  
Z Planting of October 17-30 pounds.
‘ Planting of October 24-20 pounds.
Planting of October 31-S pounds. ,
Planting of November 7-24 pounds.
{ Planting of November 14-28 pounds. s
The best yield was thus at the rate of but 14 bushels per ·
acre, while the worst was at the rate of somewhat less than 3
( bushels per acre. But it must be noted that the latest plant-
_ ing was one of the best in the matter of yield, while the earliest é_ .
i planting was one of the two worst.  
It seems to me that, so far as mere weight of yield is con- V ·
— cerned, the late plantings have done about as well as the   V
others.  
\Vhen the quality of the wheat from the different plots is  
considered, it appears that the plantings of October 3, 10, 17 A VV
and 24 stand first, while the planting of October 31 proves de-   t
· cidedly the poorest. The plot producing the most wheat also  
( produced the best, though the differences between wheats from i
the plantings of October 3, 10 and 17 were so slight as to be
s  scarcely worthy of consideration. \Vheat from each plot was
§ submitted to Mr. ll'. W. Patterson, of the Lexington Roller
  Mills, for rating, and his judgment is given below. My own
 " ‘ fr··V -— .- 1;... .

   , 236 Bulletin N0. 103.
.4 T Y rating is given beside it, and was made without knowledge of Q
i , · Mr. Patterson’s conclusions. Being based in part on data to S
  . which he did not have access, the closeness of the two is quite  
lj surprising. The weight of 10 cubic centimeters of each wheat  
  - is also given, and will be observed to verify in a general way  ·
 Q the ratings. 1
,F  Mr. Patterson’s Author’s VVeight of 10  
% I  I Date planted. rating. rating. cc.  
   _ September 26 3rd 4th 7.4 grams I
 ;_ October 3 lst lst 7.6 U
 QQ October 10 4th 3rd 7.5 i`
l . October 17 2d 2d 7.6 H
 » October 21 5th 5th 7.3 M
Q  October 31 8th Sth 6.8 " .
  November 7 7th 7th 7.5 U
  November 141 6th 6th 7.3 °`
  . That the grain from the planting of October 3 was best there
  could be no question. The seeds were larger, plumper, and
  with no defective ones. In all the other lots some shriveled ;
  1 seeds could be found, and were especially numerous in the wheat  l
Q i planted October 31, the lightest—bulk for bulk, as well as ab- ‘
'   solutely—of all. VVheat from the two latest plantings did not
Qi prove as good when closely scrutinized and weighed as was
{f expected. It was not quite as plump as that of most of the _
    early plantings, and did not seem as well matured. It was cut f f
1 g a little early, I think, and on this account, while the evidence  .
  points to the inference that very late planting will result in
  inferior grain, I am disposed to suspend judgment on this
`   point until more evidence is secured. A single test is not suf-
-   ficient basis for a conclusion.
· _ Injury by Fly in the Fall. A
VVhen it was reported in Bulletin 96 of this Station that §
on November 6, 1901, the planting of September 26 showed 33  
{ per cent. of its plants infested with fly; that the planting of  
October 3 showed 1 per cent. infested, and that none of the  
other plantings were infested at all, it was supposed, as then  
Suggested, that later examinations would prove that other plots y
` I

 r 2 E t
a l  
  Hessian Fly Experiments. 237   V
  than the two named were infested also. This seemed probable lf
  because Hessian fly eggs were found November 1 on wheat
Q planted October 17, and as this wheat was not up on October
  26, some adult fly must have been abroad after the latter date.
 l But it seems now that the eggs laid late in the season did not
  hatch, and consequently the percentages of injury remained
  practically unchanged in the plots after the date of my Hrst  
  examination (November 6). A thorough examination was  
_ made March 10, 1902, while the wheat was still in a dormant  
  hibernating condition. At this time 30 per cent. of the plants   _
  from the September 26 planting was infested with flaxseeds; i·  
P 9-10 of 1 per cent. of the planting of October 3 was infested,  
V one of the specimens found being still a larva. Neither larvae  
nor flaxseeds were found in any of the later plantings. °“  
Plots of wheat were planted again on the same ground in A; -·’'
the fall of 1902, beginning on the 15th of September. The if
season has been more open than in 1901, the first touch of
winter coming on the 25th and 26th of November, yet the
results of examinations of the different plantings of wheat con- ,
Erm, in a general way, those made in the winter of 1901-1902.
The first two plots were examined on November 21 and the ;
remainder on November 28, 1902. ·
Planting of September 15—37 per cent. infested.
¥ Planting of September 22—38 per cent. infested.
Planting of September 29——12 per cent. infested. ,,_ .
 , Planting of October 6-2 per cent. infested.  
° `I Planting of October 13—None infested. ‘
Planting of October 20-—None infested.   _
Planting of October 27—None infested.  
Injury by Fly in the Spring.  i
· it
Q e What is the influence of fall-infested wheat on non-infested  
plantings beside it during the spring? How far does the fly O
·  spread in a season from such infested wheat? These questions
were suggested by the examinations made during the fall and
winter, and have a practical interest for every grower of wheat.
It should be stated that the plantings formed one continuous
 
5
  i /
i
" ·'   e , ,

 A , T- ` if it   .
  l , 238 · Bulletin N0. 103.
it ‘ block. the consecutive plots being separated by a strip scarcely
r = V wider than that separating the drilled rows, with the earliest
  · ` planting at one end of the block and the latest at the other.
I·  _ An examination made May 12,1902, showed that the condition
 t of the wheat with reference to Hessian fly injury had changed
g · after the emergence of the winter brood, and that the insects
  had spread from the planting of September 26 to the other Q
 ig plantings, the extent of the injury in them being in proportion  ,
  to their nearness to the early planting. The flaxseeds found at
X   this time were still white in the majority of cases, and repre-
J   sented a spring brood.
l l Planting of September 26--40 per cent. infested.
V ‘ Planting of October 3-37 per cent. infested.
E Planting of October 10-23 per cent. infested. .
  _ Planting of October 17-24 per cent. infested.
Ex Planting of October 24-22 per cent. infested.
Q _ Planting of October 31-14 per cent. infested.
  Planting of November 7-17 per cent. infested.  
jg Planting of November 14-10 per cent. infested.  ,_
_ The injury, it will be observed, does not diminish regu-  
I A larly; but this could hardly be expected. Subsequently, on V
- June 15, wheat from the plots was examined by an assistant,
I I and while the percentages found were smaller than those ob-
·   tained by me early in the season, they show the relative injury  
S to be about the same. The tlaxseeds found at this time appear  
z to represent a second spring brood-the one that continues the T
  ily during the summer.  
ii Planting of September 26-32 per cent. infested.  
{ ~ Planting of October 3-25.7 per cent. infested.  
S — Planting of October 10-15 per cent. infested. ii
Planting of October 17-12.6 per cent. infested.
. A Planting of October 24-1.6 per cent. infested.
Planting of October 31-5 per cent. infested. _
; 4 Planting of November 7-#1 per cent. infested.
Planting of November 14-6.6 per cent. infested. S
The inference that may be drawn from these facts is that
wheat that has escaped the fall injury will be injured in the
spring proportionately to its nearness to fall-infested wheat.
t "

   “ t
, Hessian Fly Experiments. 239   V
‘ ,1 Yet it would be unsafe to assert that an isolated field of late
L planted wheat will never be severely injured. Though small
  and fragile, the adult Hessian fly shows a surprising activity, 4
 = and, aided by winds, is no doubt at times disseminated long
: distances from the fields in which it emerges. As an example
it may be mentioned that a small isolated planting on the Ex-
t periment Farm became infested in the spring to the extent of  
, 20 per cent. The infested wheat nearest to this planting must ·,`
i have been a quarter of a mile away, but it is possible that the N  
adults that visited it came from flaxseeds in straw at a barn   _
near by. '    
Dusting and Spraying for Hessian Fly. fg
· It is sometimes claimed that applications of lime, Paris  
' green and other materials have a beneficial effect in deter- if
ring the fly from placing its eggs on wheat. The use of lime
· dusted on the plants has been especially recommended. On
September 22, 1902, in addition to an untreated plot, two ad-
t  ditional plots were sown. Subsequently one—half of one of the `
_ plots was dusted with air-slaked lime, another was sprayed Q
with lime and Paris green in water, a thirdiwith Bordeaux mix— i
ture, and a fourth with coal-oil emulsion. Each half plot {
contained 144 acre.
‘ Dustring with Lin2e.—The first application was made Octo-
· ber 4, when two pounds of lime were used. On October 13  
two pounds more were sown over the plants. The third and `  
last application was made October 20, when two pounds were ‘ _
used.  
Twenty-five per cent, of the wheat was found to be infested  
sk with fly when it was examined November 28.   il
  Lime and Paris Green.-Tlie spray used consisted of one n   1
Q pound of Paris green, two pounds of lime and 140 gallons of  
  water. One and a half gallons of this mixture were used on {
  each of the dates October -1, 13 and 20.
  Thirty-one per cent. was infested on November 21.
  Bm·¢Zean.r J1[I·.l`l(I{7'P._‘Th€ mixture used consisted of six and
Q a half pounds of bluestone. three and a half of lime, and 32
T I
T " ·‘t.  fw     aa .

   5 1 240 Bulletin N0. 103. .
ri f N gallons of water. One and a half gallons were applied on each j
 _ ¢ ` of the following dates: October 4, 13 and 20. _
Q ‘ Nineteen per cent. was infested on November 28.
  O0aZ—0iZ Emuls-{0n.—The emulsion consisted of one-half
 i N pound of whale-oil soap in one gallon of water, churned with
N two gallons of coal-oil. One part of this was used with nine _
-   B. , of water. Applications were made on the same dates as in the  
 N._ N other treatments, one and a half gallons of the diluted emul- L
 ig sion being used each time.
  Nine per cent. was infested November 21.
 E _ The untreated wheat planted on September 22 was in-
 . fested, as will be remembered, to the extent of 38 per cent.
.    All of the treated lots may thus be supposed to have been ben-
i r eiited. But in the case of the plots treated respectively with
  lime by dusting, and with lime and Paris green in a spray, the
ti reduction in the per cent. of injury is so slight as to indicate
  that the treatment is of no practical value. The reduction
  from spraying with Bordeaux mixture is much more decided, r
  and indicates that this material could profitably be used on  
 i wheat. Its chief value is, of course, as a fungicide, and it was i'
F; only used on the wheat with the idea that if lime alone was
{ » beneficial, this mixture should prove still better. It remains
`gl to be seen to what extent it acts as a check on the red rust.
  ,. Of all the materials used, coal-oil alone approximates a com-  
  plete remedy. The reduction of the injury to 9 per cent. is  
i ; most gratifying, and is quite surprising, considering the diili- Q
gi culty of reaching all parts of the plants with a spray. It is i
if. probable that it checks the injury in part by destroying the  
j eggs. N  
Deep Plowing to Destroy the Hessian Fly.
It seems likely that an insect as small and fragile as the
: Hessian fly may be destroyed by burying it so deep in the soil
that the adult cannot make its way out. Badly infested wheat
must sometimes be plowed up to make a place for something
else. May it not be possible to destroy the ily at the same time
by very deep plowing? If good is to be accomplished, stubble

  L Hessian Fly Experiments. 241  
  might be so treated in some cases. Just to see what the indi- T
t` cations were, I had one of my assistants gather in August, i
  1902, a number of tiaxseeds and place them at different depths
it in soil in the Vivarium. The fly was so badly parasitized at the
time that only a few living tiaxseeds could be secured. Five
lots of fifteen ffaxseeds each were buried, one at a depth of
two inches, another at three, a third at four, a fourth at tive, 4%
I and the last at six inches. From the result recorded below it  
would appear that plowing to a depth of six inches would  
greatly reduce the numbers of emerging flies. `~;_ A
DEPTH` August [Sept. Emerged '    
15 16 i 17 18 19 20 l 21 I 22 24  
2inch.i 1 \ 1 i 1 2 33 %  
3 inch.` 2 \ 2 2 t 1   %  
et meh. I . 1 t ez %  
5   } \   None
6 inch., i 1 None
V The Fly in the Vivarium. _
_ The only difference between the {ly indoors and out that ·
attracted special attention was in rate of development. Broods i
kept indoors were always somewhat ahead of those in the field, `
the time depending on the condition of the weather out of
_. doors.
n Number of Broods Developed During the Season.  
The brood that developed to the Haxseed stage in the fall  
emerged in the Held as adults from about April 21 to April 24.  
  This is to be styled the winter brood.  
  The adults laid eggs at once for the first spring brood, % "
T which developed very rapidly, and was observed to be adult    
from May 21 to May 21. These adults in turn laid eggs for digg
_ the second spring brood, and were observed partly in the grub  
  and partly in the fiaxseed stage on June 3 and 4, and remained
  in the tlaxseed stage when the wheat was cut. .l’rovided no
  broods developed during the snininer on volunteer plants, this
4 gives but three broods for the year. l ain disposed to consider
' I
I lr- IT"  ·’ $:.-.;.,1.;.. ._._ _. , ...   ,.._. ,. __ ,__

  . 242 Bulletin N0. 103. A
Q, - this the full number for this region, though from a pressure of
j , ‘ other duties it has not been possible to give the subject the
., continuous attention during the summer that could be desired.
·'e  i Hessian Fly in Barley. ‘
The experimental wheat plots were planted in 1901 on e
" _— land that had been the previous spring in infested barley. In  
*   the spring of 1902 barley was planted next the plots of wheat, I
j   and it was found that when the adult flies emerged they spread
  from the wheat to the barley. From my observation thus far
Q I should say the fly attacked this grain as freely as it does
in wheat.
i The Fly in Rye.
_' But the Hy does not attack rye freely. It happened that
it some rye had been used in our drill previous to planting the
‘ lirst wheat plot in the fall of 1901, and a small quantity in the
  seed-trough was overlooked when sowing the wheat. The rye __
it came up pretty evenly scattered among the wheat. and in the  
. . spring of 1902 was pulled up and examined for liaxseeds. Not  
, a single one was found, although the wheat in the midst of  
L which the rye grew was badly infested. Rye in the regular  
, plantings on the Farm has also been examined from time to  
< time, and in no case has fly been found on this cereal. It is my  
I present opinion, therefore, that one need not fear the attacks if
  of the fly on this grain. —
it
`i The J0int·Worm in the Experimental Wheat.
·   In looking over the large numbers of wheat plants neces-
sary to get percentages of Hessian fly injury during the spring,
‘ the larva; pupae and adults of it joint-worm were frequently
l encountered within the swollen bases of the stems. They were
V not observed at all during the fall. The first larva: observed
i I . were found May $3. The stems infested by this insect could
always be distinguished from those occupied by the fly by the
swollen condition of the stem itself, the worm occupying the
interior of the swollen portion, instead of being crowded in

 2   t
. 3
Q Hessian Fly Experiments. 243  
'_ behind the sheaths of the blades. Infested stems were inva‘ if
‘   riably destroyed by the attack. On May 12, 1902, the insect
 { was found chieHy in the pupa stage, with occasional larvae and
il some adults that had not yet escaped. All but one of the ex-
I perimental plots were infested, but unevenly so, as will appear
 I from the following record made at the time:
Planting of September 26——2O per cent. infested. \'
°   Planting of October   per cent. infested. ‘=
l Planting of October 10—10 per cent. infested. Z
Planting of October 17-17 per cent. infested. \ ii
Planting of October 24—21 per cent. infested. ‘.  
Planting of October 31-8 per cent. infested.  
Planting of November 7—None infested.  
Planting of November 14-2 per cent. infested.  
The adults were found to be common on the blades May  
17, when many examples were collected by sweeping. They  
were still to be taken from the blades on May 21. I consider
the insect found here to be the Isosonza grande, Hrst described
by C. V. Riley, and subsequently noticed by Professor S. A.
  Forbes in his third annual report (1885, p. 34) as State Ento- `
¤ mologist of Illinois. In color my material agrees with the _
descriptions of these authors, but my specimens, preserved dry f
— and in fluid, are smaller. in no case reaching a length of four {
millimeters, averaging about 3.7m!n. \Vith one exception all
  of the many specimens collected are winged. The single wing- `
g less example measures but 2 millimeters in length, and   ,
` appears to pertain to the species long known under the name ~"'°`
Q 1s0s0nza tritici. i
Summary.  
.  
3* The observations and experiments thus far made in the g `~
i field and in the Vivarium point to the following conclusions,   =
though they are not considered final results:  
1.lTo escape severe fall injury from the ily wheat should  
  not be planted in this part of Kentucky before the 6th of Octo-
{5 ber. The Sth or 10th of this month will probably prove safer
  dates during very mild falls.
_Q 2. Wheat that, from late planting, has escaped fall injury

 , f" ` l    
if  r 244 _ Bulletin N0. 103. · »
2  entirely may, the following spring, be badly damaged if it  
 A r ` stands near infested wheat.  
 .  3. Very deep plowing will destroy many of the flies in  
 l infested stubble.  
"  · 4. Spraying with dilute coal-oil emulsion reduces injury   ·
  I from the fly.  ll
. _ 5. Spraying with Bordeaux mixture reduces injury, but  4;
4, $ not as decidedly as the emulsion. gil *
 _   6. Lime and Paris green in water, and dry lime alone, are t
  of no practical benefit.
ls 7. Barley is as susceptible to attack as wheat.
if  8. Rye is but little, if at all, injured by Hessian fly.
Q 9. Three annual broods of the fly develop in Eastern Ken-
  tucky.
I
ii .
@1f
P
¤
x "