New control methods for the pear thrips and peach tree borer

■university of CALIFORNIA SAN DIEGO

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^ JOi-U, CALIFORNIA 9203d

13 1822 01677 8425

UNIVERSITY OF CALIFORNIA PUBUCATIONS

COLLEGE OF AGRICULTURE

AGRICULTURAL EXPERIMENT STATION

New Control Methods

LIBRARY FADL in

972 9

T Thrips and Peach Tree Borer

Earl L. Morris

Sprayed lor Thrips.

Unopmycd.

BULLETIN No. 228
(Berkeley, Cal.)

SACRAMENTO
:nd Wm. Richardson - - Superintendent ok Statk Printinu
19 12

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UNIVERSITY OF CALIFORNIA SAN DIEGO

UmM^n^^'^^^'^''^- SAN DIEGO
^ JOLU, CALIFORNIA S2Q3S

3 1822 01677 8425

UNIVERSITY OF CALIFORNIA PUBUCATIONS
COLLEGE OF AGRICULTURE

AGRICULTURAL EXPERIMENT STATION

New Control Methods

'car Thrips and Peach Tree Borer

Earl L. Morris

- '" v^'. r-7»««-'i«..«33i«» :f^ t^3-V "

Sprayed {or Tlirips.

BULLETIN No. 228

(Berkeley, Cal.)

SACRAMENTO
Friend Wm. Richaboson - - Superintendent of State Printing

1912

Benjamin Ide Wheeler, President of the University.

EXPERIMENT STATION STAFF.

E. J. WiCKSON, M.A., Director and Horticulturist.

E. W. HiLGARD, Ph.D., LL.D., Chemist (Emeritus).

W. A. Setchell, Ph.D., Botanist.

LiEROY Anderson, Ph.D., Dairy Industry and Superintendent University Farm Schools.

M. E. Jaffa, M.S., Nutrition Expert.

R. H. Loughridge, Ph.D., Soil Chemist and Physicist (Emeritus).

C. W. WOODWORTH, M.S., Entomologist.

Ralph E. Smith, B.S., Plant Pathologist and Superintendent of Southern California

Pathological Laboratory and Experiment Station.
G. W. Shaw, M.A., Ph.D., Experimental Agronomist and Agricultural Technologist, in

charge of Cereal Stations.

E. W. Major, B.Agr., Animal Industry.

B. A. Etcheverry, B.S., Irrigation Expert.

F. T. Bioletti, B.S., Viticulturist.

W. T. Clarke, B.S., Assistant Horticulturist and Superintendent of University Exten-
sion in Agriculture.

John S. Burd, B.S., Chemist, in charge of Fertilizer Control.

J. E. CoiT, Ph.D., Assistant Pomologist, in charge of the Citrus Experiment Station
Riverside.

George E. Colby, M.S., Chemist (Fruits, Waters and Insecticides), in charge o]
Chemical Laboratory.

H. J. Quayle, M.S., Assistant Entomologist.

H. M. HalLj Ph.D., Assistant Botanist.

C. M. Haring, D.V.M., Assistant Veterinarian and Bacteriologist.
E. B. Babcock, B.S., Assistant Agricultural Education.

W. B. Herms, M.A., Assistant Entomologist.

W. T. HoRNE, B.S., Assistant Plant Pathologist.

C. B. LiPMAN, Ph.D., Soil Chemist and Bacteriologist.

A. J. Gaumnitz, Assistant Agronomist, University Farm, Davis.
N. D. Ingham, B.S., Assistant in Sylviculture, Santa Monica.

T. F. Hunt, B.S., Assistant Plant Pathologist.

P. L. McCreary, B.S., Chemist in Fertilizer Control.

E. H. Hagermann, Assistant in Dairying, Davis.

R. M. Roberts, Farm Manager, University Farm, Davis.

B. S. Brown, B.S.A., Assistant Horticulturist, University Farm, Davis.
J. I. Thompson, B.S., Assistant Animal Industry, Davis.

J. C. Bridwell, B.S., Assistant Entomologist.
L. Bonnet, Assistant Viticulturist.

F. C. H. Flossfeder, Assistant in Viticulture, University Farm, Davis.
P. L. HiBBARD, B.S., Assistant Fertilizer Control Laboratory.

C. H. McCharles, M.S., Assistant Agricultural Chemical Laboratory.

B. A. Madson, B.S.A., Assistant Experimental Agronomist.
Howard Phillips, B.S., Assistant Animal Industry, Davis.

Walter E. Packard, M.S., Field Assistant Imperial Valley Investigation, El Centro
L M. Davis, B.S., Assistant in Dairy Husbandry, University Farm, Davis.
S. S. Rogers, B.S., Assistant Plant Pathologist, Plant Disease Laboratory, Whittier
H. A. RuEHE, B.S.A., Assistant in Dairy Husbandry, University Farm, Davis.

C. O. Smith, M.S., Assistant' Plant Pathologist, Plant Disease Laboratory, Whittier

E. H. Smith, M.S., Assistant Plant Pathologist.

C. L. ROADHOUSE, D.V.M., Assistant in Veterinary Science.

F. M. Hayes, D.V.M., Assistant Veterinarian.

M. E. Stover, B.S., Assistant in Agricultural Chemical Laboratory.

W. H. VOLCK, Field Assistant in Entomology, Watsonville.

E. L. Morris, Field Assistant in Entomology, San Jose.

E. E. Thomas, B.S., Assistant Chemist, Plant Disease Laboratory, Whittier.

A. B. Shaw, B.S., Assistant in Entomology.

G. P. Gray, M.S., Chemist in Insecticides.

H. D. Young, B. S., Assistant in Agricultural Chemistry, Plant Disease Laboratory

Whittier.
A. R. Tylor, B.S., Assistant in Plant Pathology, Plant Disease Laboratory, Whittiei
L. T. Sharp, B.S., Assistant in Soils.
W. W. Cruess, B.S., Assistant in Zymology.
J. F. Mitchell, D.V.M., Assistant in Veterinary Laboratory.
W. B. Boys, Assistant Cerealist.
M. E. HoLTER, B.S., Assistant Soil Chemist.

Anna M. Lute, Scientific Assistant, United States Department of Agriculture.
J. C. Roper, Patron, University Forestry Station, Chico.
E. C. Miller, Foreman, Forestry Station, Chico.

D. L. Bunnell, Secretary to Director.

NEW CONTROL METHODS

FOK" Tin;

PEAR THRIPS AND PEACH TREE BORER.

liy E.VKI. 1>. AhiKui^.

[Introductory Notes. — The present Bulletin gives the pi-aetical results of studies
on the two most serious pests in the Santa Clara Valley. They were conducted by
Mr. Morris under the auspices of the Experiment Station. Very decided progress
was made towards the control of these insect.s, both of which extend into other parts
of the State and are causing much concern at the present time.— ('. W. Woodwohtii. I

LIME SPRAY FOR THRIPS (Euthrips pyri).

This paper is based on an experiment in a pear oi-chard belonging?
to W. C. Bogen on San Tomas Road, near San Jose, ('idifornia. It was
possible to make this experiment, which extcMich^d over two seasons.

^

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Fig. 1. — Whitewashed tree coming out into full bloom.

368

UNIVERSITY OF CALIFORNIA — EXPERIMENT STATION.

solely through the hearty cooperation of Mr. Bogen, who at all times
gave freely of his time, money and counsel.

The period covers the fruiting season of 1910 and 1911. The writer
had observed that in some instances pear trees sprayed with a heavy
solution of home-cooked lime-sulphur, which contained a large excess
of lime, were freer from attacks of thrips than pear trees in the same

Fig. 2.-

-Unspi-ayed trees at blossoming time. This tree is adjacent to tlie one sliown

in figure 1.

orchard which were not sprayed. From previous experiments it seemed
highly improbable that sulphur in chemical combination with the lime
was the active agency. The only other possible agency was the free
lime which Avas sufficient to make a thin whitewash. Acting on the
above suggestion in the spring of 1910, we sprayed four rows of pear
trees, thirty-one trees in a row, and three trees on each of the next

Bulletin 228] pear thrips and pp:acii trkk borkr. 369

two rows, making in all one huiulrcd tliirt}' trees. This was six trees
more than one sixth of the orchard, and the adjacent unsprayed trees
made an excellent check. The application was made witli a hand pump,
without constant agitation, with the result tluit the last wiiitt'wash
sprayed from the tank was much thicker than the first. The last trees
sprayed, especially the last six, which were in unsprayed rows, were
covered with a very thick, heavy whitewash. This application was made
when very few blossom buds were open sufficiently to admit tlie llirips.
At the time of full blossom it was very apparent that the nund)er of
blossoms was in direct proportion to the amount of whitewash. The
trees which had a thin coating of whitewash had very few blossoms;
those which had a ver}' thick coating of whitewash had abuiulanc(!
of blossoms. Fig. 1 shows thickly whitewashed trees in full I)lo()m.
Fig. 2 shows adjacent unsprayed trees with very few blossoms, the
blossom buds having been destroyed by the thrips. The amount of
fruit corresponded to the amount of blossom.

The season of 1911 the experiment was repeated on a larger scale.
Between one and two weeks before the time for the buds to open.
Mr. Bogen sprayed a large number of trees verj- thoroughly with thick
whitewash. Time is a great factor in the control of thrips, and we
had hoped to show from this experiment that the whitewash A\()uld
have the same beneficial effect when applied a week or more before the
buds open as when applied at the time of opening An exceedingly
heavy downpour of rain washed the lime from the buds and defeated
our plans. By the time the orchard was again dry enough for spray-
ing, the buds Mere just beginning to open and conditions were ripe for
duplicating the experiment of the previous season.

About one half of the orchard was used for the experiment. It con-
sisted, including checks and sprayed trees, of seven rows, thirty-six
trees to the row. The same material was used as in the previous experi-
ment. Two rows were sprayed, one row unsprayed, two sprayed, two
unsprayed, with this exception, that in the one unsprayed row of trees
seven trees were spraj-ed bj^ mistake.

The results were the same as the previous year. All the sprayed
trees, including the seven in the unsprayed row, came into full blossom.
The unsprayed trees blossomed very feebly. The fruit corresponded
very closely to the blossoming. The spraj^ed trees averaged eight times
as much fruit as the unsprayed trees. Fig. 3 shows sprayed and
unsprayed trees at picking time. Fig. 4 shows the fruit from a sprayed
and an unsprayed tree.

We used eighty (80) pounds of quicklime for one hundred (100) gal-
lons of spraying material. The whitewash was strained through one
fourteenth (1/14) inch mesh wire screen and the same sized screen u.sed
on the suction hose of the pump. The ordinary Bordeaux no/zles

370

UNIVERSITY OF CALIFORNIA — EXPERIMENT STATION.

Fig. 3. — Trees at harvest time ; the lower one was whitewashed and carries fruit.

Bulletin 228]

PEAR THRIPS AND PEACH TKEE UdUKU.

371

worked well. But it was necessary to enlarge slightly the opening in llio
disks of Vermorel type nozzles. We found it very important to have
the lime properly slaked. Good lime properly slaked is of creamy con-
sistency, with a negligible amount of grit. It forms a smooth, uniform,
creamy coating on the tree. An attempt to use improperly slaked limr
will usually result in complete failure. No amount of written inslruf
tion will teach one to slake lime. The laiowledge must come from actual
work with some one who has had the experience.

In orchard practice we found it convenient to have our slaking vat,
which was 6 by 4 by 1 feet, elevated about three feet, with one end
slightly lower than the other. In the lower end we arranged a sliding
door through which the whitewash flowed by gravity into a containing

(Unsprayed. ) (Whitewashed.)

Fig. 4. — Fruit at harvest from treated and untreated trees.

vat. The lower vat was shorter, narrower, and deeper than the slaking
vat to facilitate the removal of the material to the spray tank. Between
the two vats we arranged a piece of window screen, of one fourteenth
inch mesh, supported by chicken fencing, through which the whitewash
passed in flowing from the slaking vat.

The cost of material ranges from one (1) to one and one half (1^)
cents per gallon, depending upon the cost of lime and labor. One
application proved sufficient to protect the blossoms and permit setting
of fruit. We did not find it necessary to spray a second time for larva\
although in the first experiment enough larvje appeared to lead us to
believe that in some cases a second spraying would be necessary with
some good contact spray.

372

UNIVERSITY OF CALIFORNIA EXPERIMENT STATION.

ASPHALTUM TREATMENT FOR THE PEACH TREE BORER.

The western peach tree borer (Sanninoidea pacifica) is an insect
of much economic importance in the horticultural district about the
southern arm of San Francisco bay.

The investigations upon which this paper is based were made in
most part in the peach orchard of the J. H. Flickinger Company,
Berryessa, California. They have extended over a period of four years.
The results have not been verified for other districts.

The adult borers are slender, blue-black, day-flying moths, about one
inch long. They are seldom seen and very rarely recognized by the
orchardists. They issue more or less from February to September, but

■f J •: rW

fei^r -^^

Pig. 5. — Work of the peach tree borer.

the mass of them appear about the middle of July. They place the eggs
on the trunk of the tree from the ground up two feet, one to twenty-five
eggs in a place. These are very small and generally escape notice. They
hatch in a few days.

The newly hatched larvge, or "worms," which are difficult to find,
usually enter the bark at or near the ground. The new burrow is
marked at first by light brown bark dust, which in a few hours dis-
appears, after which it is nearly impossible to find the opening. The
larvae grow rapidly, work their way through the bark, and spend most
of their life between the bark and wood, where they may do great

BlLLETIX 228]

PEAR THRIP9 AND PEACH TREE BORER.

373

damage by boring long distances, often completely girdling the trees.
Gum flows as a result of this injury and is a fairly reliable indication
of the presence of the large "worms." Unfortunately there is nothing
to show the presence of the small "worms."

The full-grown larvce are about one inch long and the diameter of a
slate pencil. They have white bodies and dark brown heads. When
ready to pupate, they seek places from which the moths can easily
issue and construct about themselves cocoons from the chewed-up wood
and bark. The cocoons are light brown capsule-shaped bodies, slightly
larger than the "worms." They may be found under the bark, in tlie
bark, or in the ground an inch or more from the tree.

The usual method of combating the peach borer is to dig out the
"worms" during the winter season, but often the knife causes more
damage than the borers, especially if the digging must be done con-

FiG. 6. — The asphaltum treatment for the peach tree borer.

«ecutive years or by careless workmen. In the fall the soil is removed
from the base of the tree to a depth of six or eight inches and the borers
dug. In the spring they are dug again and the soil replaced. The
second digging is necessary because in the fall manj^ of the "worms" are
too small to be found.

Many preparations are being used on the trunks of trees ; some to
keep the moths from depositing eggs, some to prevent the "worms"
from entering, some to kill the "worms" after they have entered. None
of these have been wholly satisfactory. Experiments along these lines
by the writer led to the use of hard asphaltum, grades "C" and "D."
with good results. This was applied early in the spring to badly infested
trees from which the borers had not been dug. It was found that a
thick heavy coating prevented both the issuance and the entrance of
about 95 per cent to 98 per cent of the insects, the degree of efficiency
•depending upon the thoroughness of the application. Asphaltum does

374 UNIVERSITY OF CALIFORNIA — EXPERIMENT STATION.

not penetrate, crack, deteriorate, or bind the tree, since it yields to the
slightest pressure. Four years of experimenting have not shown the
least injury.

The material is applied warm with a brush from five inches below
to five inches above the ground. It is easier to apply two or more coat-
ings than to try to put on more at one time than will adhere firmly. The
first coating will harden very quickly and the second can be applied
without loss of time. Two coatings are generally sufficient unless the
bark is very rough. But in any case a thick, uniform covering is abso-
lutely necessary for the best results.

Borers are seldom uniformly distributed over an orchard. Small
blocks of trees here and there may be badly infested and the most of
the orchard comparatively free from the pest. In such cases it is not
necessary to treat all of the trees with asphaltum, but it is necessary to
examine them carefully, for in no other way can the true conditions
be known.

A convenient way to handle the asphaltum is to mount an iron kettle
on the running gear of an orchard truck and suspend beneath it a sheet-
iron apron as a fire box. Keep hard asphaltum in the kettle all the time
so that the melted asphaltum will not get too hot to carry in small con-
tainers and apply directly to the trees.

We have also used asphaltum to a limited extent for covering wounds
and for grafting. And although our experiments are not completed, we
believe it may become very useful as a dressing for tree surgery.

SUMMARY.

In the fall throw the soil away from the trees and dig the borers. In
the spring dig the borers again and apply a thick coating of asphaltum
and replace the soil. Examine the trees each subsequent year to remove
borers and to repair any thin or broken places in the asphaltum coating.

STATION PUBLICATIONS AVAILABLE FOR DISTRIBUTION.

REPORTS.

1SJ6. Report of the Viticultural Work during the seasons 1887-93, with data resiiud-
ing the Vintages of 1894-95.

18LI7. Resistant Vines, their Selection, Adaptation, and Grafting. Appendix to Viti-
cultural Report for 1896. '

1902. Report of the Agricultural E.xperiment Station for 1898-1901.

VJ03. Report of the Agricultural Experiment Station for 1901-03.

J:^04. Twenty-second Report of the Agricultural E.xperiment Station for 1903-04.

BULLETINS.

print. Endurance of Drought in Soils of

the Arid Regions.
. 128. Nature. Value, and Utilization of

Alkali Lands, and Tolerance of

Alkali. (Revised and Reprint,

1905.)
133. Tolerance of Alkali by Various

Cultures.
147. Culture work at the Sub-stations.
162. Commercial Fertilizers. (Dec. 1,

1904.)

167. Manufacture of Dry Wines in

Hot Countries.

168. Observations on Some Vine Dis-

eases in Sonoma County.

169. Tolerance of the Sugar Beet for

Alkali.

170. Studies in Grasshopper Control.

171. Commercial Fertilizers. (June

30, 1905.)
174. A New Wine-cooling Machine.

176. Sugar Beets in the San Joaquin

Valley.

177. A New Method of Making Dry

Red Wine.

178. Mosquito Control.

. 179. Commercial Fertilizers. (June,
1906.)

181. The Selection of Seed- Wheat.

182. Analysis of Paris Green and

Lead Arsenic. Proposed In-
secticide Law.

183. The California Tussock-moth.

184. Report of the Plant Pathologist

to July 1, 1906.

185. Report of Progress in Cereal In-

vestigations.

186. The Oidium of the Vine.

187. Commercial Fertilizers. (Janu-

ary, 1907.)

188. Lining of Ditches and Reservoirs

to Prevent Seepage and Losses.

189. Commercial Fertilizers. (June,

1907.)

190. The Brown Rot of the Lemon.

191. California Peach Blight.

192. Insects Injurious to the Vine in

California.

193. The Best Wine Grapes for Cali-

fornia ; Pruning Young Vines ;
Pruning the Sultanina.

194. Commercial Fertilizers. (Dec,

1907.)

No. 195.
197.

198.
199.
200.

201.

202.

203.

204.

205.

206.

207.
208.
209.
210.

211.

212.
213.
214.
215.

216.

217.
218.
219.

220.

221.

222.
223.
224.

225.

226.
227.

The California Grape Root-worm.

Grape Culture in California ; Im-
proved Methods of Wine-mak-
ing ; Yeast from California
Grapes.

The Grape Leaf-Hopper.

Bovine Tuberculosis.

Gum Diseases of Citrus Trees in
California.

Commercial Fertilizers. (June,
1908.)

Commercial Fertilizers. (Decem-
ber. 1908.)

Report of the Plant Pathologist
to July 1, 1909.

The Dairy Cow's Record and the
Stable.

Commercial Fertilizers. (Decem-
ber, 1909.)

Commercial Fertilizers. (June,
1910.)

The Control of the Argentine Ant.

The Late Blight of Celery.

The Cream Supply.

Imperial Valley Settlers' Crop
Manual.

How to Increase the Yield of
Wheat in California.

California White Wheats.

The Principles of Wine-making.

Citrus Fruit Insects.

The House Fly in its Relation to
Public Health.

A Progress Report upon Soil and
Climatic Factors Influencing
the Composition of Wheat.

Honey Plants of California.

California Plant Diseases.

Report of Live Stock Conditions
in Imperial County. California.

Fumigation Studies No. 5 ; Dos-
age Tables.

Commercial Fertilizers. (Oct.
1911. J

The Red or Orange Scale.

The Black Scale.

The Production of the Lima
Bean.

Tolerance of Eucalyptus for
Alkali.

The Purple Scale.

Grape Vinegar.

d

CIRCULARS.

No. 1. Texas Fever.

7. Remedies for Insects.
9. Asparagus Rust.

11. Fumigation Practice.

12. Silk Culture.

15. Recent Problems in Agriculture.
What a University Farm is For.
19. Disinfection of Stables.

29. Preliminary Announcement Con-

cerning Instruction in Practical
Agriculture upon the Univer-
sity Farm, Davis, Cal.

30. White Fly in California.

32. White Fly Eradication.

33. Packing Prunes in Cans. Cane

Sugar vs. Beet Sugar.

36. Analyses of Fertilizers for Con-
sumers.

39. Instruction in Practical Agricul-
ture at the University Farm.

46. Suggestions for Garden Work in
California Schools.

4 8. Butter Scoring Contest, 1909.

50. Fumigation Scheduling.

No. 52. Information for Students Con-
cerning the College of Agricul-
ture.

55. Farmers' Institutes and Univer-
sity Extension in Agriculture.

58. Experiments with Plants and
Soils in Laboratory, Garden,
and Field.

60. Butter Scoring Contest, 1910.

61. University Farm School.

62. The School Garden in the Course

of Study.

63. How to Make an Observation

Hive.

64. Announcement of Farmers' Short

Courses for 1911.

65. The California Insecticide Law.

66. Insecticides and Insect Control.

67. Development of Secondary School

Agriculture in California.

68. The Prevention of Hog Cholera.

69. The Extermination of Morning-

Glory.

70. Observations on the Status of

Corn-growing in California.