Group Title: Bulletin University of Florida. Agricultural Experiment Station
Title: The bean leaf-hopper and hopperburn with methods of control
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Permanent Link: http://ufdc.ufl.edu/UF00026766/00001
 Material Information
Title: The bean leaf-hopper and hopperburn with methods of control
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Alternate Title: Bean leaf hopper and hopperburn with methods of control
Physical Description: p. 61-88 : ill. ; 23 cm.
Language: English
Creator: Beyer, A. H ( Adolph Harvey ), b. 1882
Publisher: University of Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1922
Copyright Date: 1922
 Subjects
Subject: Beans -- Diseases and pests -- Florida   ( lcsh )
Beans -- Diseases and pests -- Control -- Florida   ( lcsh )
Leafhoppers   ( lcsh )
Leafhoppers -- Control   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Includes bibliographical references.
Statement of Responsibility: by A.H. Beyer.
General Note: Cover title.
 Record Information
Bibliographic ID: UF00026766
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: ltuf - AEN3319
oclc - 18171256
alephbibnum - 000922810

Full Text


Bulletin 164 June, 1922
UNIVERSITY OF FLORIDA
Agricultural Experiment Station

The Bean LeafHopper and Hopperburn

With Methods of Control
By
A. H. BEYER


















11 A
,x












-ANB-

Fig. 13.-A bean leaf affected by the feeding of bean leaf-hoppers; and-both
adults and nymphs
Bulletins will be sent free upon application to the Experiment Station,
GAINESVILLE, FLORIDA








THE BULLETIN IN BRIEF
The bean leaf-hopper, Empoasca mali, is a sucking insect,
being similar in this respect to other leaf-hoppers. Both the
adults and nymphs feed only on the mid-vein and its branches
and seem especially fond of the upper portion or tip of the
leaf. The sucking of sap from these leaf veins seriously affects
the life of the plants. The amount of sap lost depends upon the
abundance and also upon the size and age of the insects.
As a result of this insect injury, the plants turn yellow and
their leaves curl up. A distinct injury produced is known as
"hopperburn" and starts by a slight yellowing at the tip of the
leaf. As this injury gradually spreads, the leaf turns brown,
curls upward at its tip and margin and finally withers. If
the infestation is slight, the basal area of the leaf may remain
green.
Hopperburn on beans seems to spread more rapidly with hot
dry weather than with cool, moist weather. Spraying with bor-
deaux mixture serves to control hopperburn.
In the latitude of Gainesville the bean leaf-hopper becomes
abundant early in summer and destructive outbreaks occur thru-
out late summer and fall. They disappear gradually in Novem-
ber and December. The older adults die in winter, while the
younger ones find winter quarters in protected places near some
of their favorite host plants.
, The host plants are many, the favorites being beans, pota-
toes, beets, cucumbers and lettuce. Eggs are deposited in the
mid-veins, the branches of the mid-vein and sometimes the
petioles of the leaves. The hatching period averaged nine days,
and the five instars averaged 19 days.
As many as five or six generations may appear within a year.
Only adults pass thru the winter.
The bean leaf-hopper has no natural enemies of economic
importance, altho with a warm wet season a parasitic fungus
has been found to be quite effective in destroying this insect.
Spraying with bordeaux mixture, 4-4-50 formula, to which
should be added 1/2 pint of nicotine sulphate to 50 gallons of the
bordeaux, applied with a special spraying apparatus at a pres-
sure of 200 pounds, gives good results. From four to six ap-
plications are required to control the leaf-hopper and prevent
hopperburn, depending upon the abundance of the infestation,
the season of the year and the condition of the weather.












THE BEAN LEAF-HOPPER AND HOPPERBURN
WITH METHODS OF CONTROL
By A. H. BEYER

INTRODUCTION
The serious injury of the bean leaf-hopper to the growing
bean crop of Florida has resulted in the truckers placing this
insect for a number of years at the head of the list of insects
harmful to snap beans. The growing desire of these truckers
for information on the habits and control of this pest in Florida
has led the author to study its life history, habits, food plants,
destructiveness and control.
Since the bean leaf-hopper is recorded in literature and gen-
erally spoken of under a variety of names, among the most com-
mon being the apple leaf-hopper, the currant leaf-hopper, the
potato leaf-hopper, the green fly and the Hessian fly, it is pro-
posed that it be called "bean leaf-hopper," as mentioned in Bul-
letin 151 of this station, because it attacks snap and pole beans
particularly.






Fig. 14.-Out-door laboratory, green house and rearing cages in which
were conducted some of the experiments of this bulletin
DISTRIBUTION OF THE BEAN LEAF-HOPPER
Outside the United States records show that the bean leaf-
hopper occurs in British Columbia, Okanagan, Nova Scotia, the
Province of Ontario, Mexico, Porto Rico, and Corrientes, Argen-
tina.
It has been reported as appearing in nearly every state in
this country, and is recorded in greatest abundance in the
region of the eastern humid area of the Upper Austral Zone,
or in the southeastern part of the United States.
In Florida the writer's investigations in 1921 indicated a
general distribution over the entire state. But it occurs per-








64 Florida Agricultural Experiment Station

haps with greatest abundance thruout the year in the southern
part of the state. This widespread occurrence may be due to
the fact that the winter months of 1921 and 1922 were very
mild.









































Fig. 15.-The castor bean is a winter host plant of the bean leaf-hopper.
Note affected lower leaves







Bulletin 164, The Bean Leaf-Hopper 65

FOOD PLANTS OF THE BEAN LEAF-HOPPER
It has been found that the bean-hopper lives upon a wide
range of plants, both wild and cultivated. In the latitude of
Gainesville during early spring it was first found on poke weed
and castor bean. Later it was found on the velvet bean, the
cowpea and the cultivated sunflower, and still later upon snap
beans and potatoes. Among the various trees it attacks in sum-
mer during dry seasons when food is scarce, are the various
oaks and citrus trees and the red maple.
A list of its host plants, recorded during the summer of 1921,
follows:
Pecan, Hicoria pecan Eggplant, Solanum melongena
Red maple, Acer drummondii Beggarweed, Meibomia tortuosa
Peach, Amygdalus persica Wild morning glory, Convolvulus
Wild beans, Phaseolus sp. arvensis
Beans, Phaseolus vulgaris Rye, Scale cerale
Cowpeas, Vigna simensis Mulberry, Morus rubra
Poke weed, Phytolacca decandra Plums, Prunus sp.
Castor bean, Ricinus sp. Strawberry, Fragaria sp.
Irish potato, Solanum tuberosum Blackberry, Rubus sp.
Sweet potato, Ipomoea batatas Lettuce, Lactuca sativa
Sunflower, Helianthus sp. Beets, Beta vulgaris
Ragweed, Ambrosia artemisiaefolia Cucumber, Cucumis sativus
Hollyhock, Althaea rosae Roses, Rosa sp.
Ground cherry, Physalis pubescens Grapes, Vitis sp.
Sorghum, Andropogon sorgum Orange,
Crab grass, Syntherisma sanguinale Tangerine,
Oats, Avena sativa Kumquat, Citrus sp
Corn, Zea mays Grapefruit,
Barley, Hordeum vulgare
Johnson grass, Andropogon hale-
pensis
Winter Host Plants.-In reviewing the year's investigations
it is noticed that this insect frequents certain cultivated plants
but very little during part of the year. In the latitude of
Gainesville, where our studies were conducted most extensively,
the insect was observed first on castor bean and poke weed in
the field about March 2. These plants were growing in fence
corners, and it was upon their lower leaves that the insects
were discovered.
As the growing season progresses the insects leave the castor
bean and poke weed and attack beans and other cultivated
plants. In fall when these crops are exhausted they return to
the plants they left in the spring. (See fig. 15.) Here they







66 Florida Agricultural Experiment Station

remain until the first killing frost, when they seek shelter in
protected places nearby.
Latitude and Wintering.-With reference to the effect of lati-
tude upon hibernation (or over-wintering) the writer's field in-
vestigations disclosed the following data:

On February 1, 1921, in South Florida, south of the lati-
tude of Lakeland no evidence of hibernation of the species
in question could be found. All stages of the life cycle
were found in abundance on favorite host plants. Prob-
ably their occurrence was an annual one, due to the fact
that no killing frost had visited that section up to that
time.

ECONOMIC IMPORTANCE
In accounts of this insect's damage to beans over the state,
its seriousness is indicated by the use and the occurrence of
such words as "much dreaded," "the destructive" and other











Fig. 16.-These beans-two weeks old-were not sprayed for control of the
bean leaf-hopper
similar expressions. The insect frequents the bean crop in all
parts of the state and it is commonly said that especially a
fall crop cannot be grown successfully, unless the bean leaf-
hopper is avoided. Under natural conditions this can be done
only in the spring. The growing of summer and fall crops of
beans is not possible in most parts of the state. The loss to
commercial growers of bush and pole beans is known to be
tremendous, especially in the fall, when the entire crop is de-
stroyed. There is not a single home garden planted in the fall
that doesn't suffer severely from the work of this pest. Added
together, the losses for any one year represent a big sum of
money.







Bulletin 164, The Bean Leaf-Hopper 67















Fig. 17.-One spraying just as the first leaves were forming greatly bene-
fited this crop of beans
















Fig. 18.-Where spraying was done systematically the beans looked like this

The combined loss caused by the attack of the bean leaf-
hopper and the accompanying "hopperburn" (which is described
later), takes first place in Florida among all bean troubles. It
is essential, therefore, that growers become familiar with the
insect, with the nature of its injury, and with methods for its
control.

HOT, DRY WEATHER FAVORS SPREAD OF INSECTS AND
HOPPERBURN

With periods of hot, dry weather there occurs a more rapid
growth of the stages of the leaf-hopper, and during these pe-
riods they are much more abundant. Hopperburn likewise







68 Florida Agricultural Experiment Station

spreads much
mo r e rapidly
during hot, dry
weather. The
amount of soil
moisture seems
to have con-
siderable influ-
ence upon the
development of
hopperburn.
Even with an
equal number
of lea f-hop-
pers, it has
been observed
that when the
weather is
humid and the
soil is reason-
ably moist,
there is less in-
jury from hop-
perburn. On
the other hand,
-it has been
noticed that
when the
weather is ex-
cessively d r y Fig. 19.-A bean leaf, dead as the result of the attacks
of the bean leaf-hopper. Veins and chlorophyll of
and soil moist- the leaf were destroyed; an extreme case of hopper-
ure very burn.
scarce, the injury becomes more abundant.
In 1921 it was hottest during June, the thermometer reaching
1010 F. that month. The mean maximum temperature for the
season was 86.3 F., somewhat above the normal temperature
for Gainesville. The latter half of the summer was dry and
hot, except June, which had a normal rainfall of about 5.7 inches.
July was above normal, having a rainfall of 15.03 inches. Oc-
tober, with 6.03 inches, was about normal.








Bulletin 164, The Bean Leaf-Hopper 69





















Fig. 20.-Difference in growth between sprayed and unsprayed plants
Since the bean leaf-hopper has been recorded as reaching the
height of its development during hot, dry weather, it is con-
clusive that 1921 afforded this species a very favorable season
for its development. However, the long drought of that year
caused much truck to perish and this resulted in the destroying
of countless numbers of immature insects, while the adults
sought citrus and shade trees for food. Among the most ser-
iously attacked trees observed was the red maple.
HOW TO KNOW THE INSECT
Description and Habits of the Adult.-The adult' or mature
bean leaf-hopper is a very small insect about one-eighth of an
inch in length. It has a pale green color with large whitish
eyes. This species is generally distinguished by a more or less
distinct "H" on the top of its body between the head and base
of its wings. Above this "H" occur six circular whitish spots,
while below it occur three whitish, wedge-shaped spots.
The adults are very timid and active, and when even slightly
disturbed seek protection by instantly hopping or flying away
to a place of concealment and safety. On warm sunny days they
are especially active, and when the least disturbance occurs they
rise in swarms.
"Empoasca mali, Lab., order Hemiptera, family Cicadellidae.








70 Florida Agricultural Experiment Station

Description of the Egg.-The eggs are laid singly in slits
made in the sides of the veins and the stems of the leaves.
The eggs are difficult to find, being only about three-one-hun-
dredths (3/100) of an inch in length, and are first located by












:% u I'



A




















Fig. 21.-Drawings of the adult bean leaf-hopper; a, dorsal view; b, ventral
view showing mouth parts and reproductive organs (f the female; c,
lateral view, showing body and mouth parts. Also drawings showing the
various nymphal stages; d, first stage; e, second stag( ; f, third stage;
g, fourth stage; h, fifth stage. I represents where an egg is deposited
in the mid-vein, as well as an egg highly magnified.






Bulletin 164, The Bean Leaf-Hopper 71

the scars in the veins of the leaves in which they are laid. It
was found that they are most commonly deposited in the mid-
rib, near the tip, of the leaf (see fig. 21). The eggs are min-
ute and transparent, their shape being elongated and slightly
arched from end to end, the ends tapering bluntly, especially
the anterior end. At hatching time the egg assumes a pale
yellow color, and the eyes of the unhatched nymphs appear
red in color as seen thru the egg membranes.
Description of Various Stages of Nymphs.-The nymph in its
first stage is about four-one-hundredth (4/100) of an inch in
length. Soon after hatching and starting to feed the nymph
changes from a whitish color to a light yellow. The eyes are
reddish. Small spines are found on the back side of the head,
thorax and abdomen. On the abdomen these spines are arranged
in four rows parallel with the body. The body segments are
slightly narrower than the head and taper bluntly at the rear
end (see fig. 21, d). The nymph is not very active, moving by
hops and sidewise running motions, similar to that of a fiddler
crab.
The nymph in its second stage is about five-one-hundredth
(5/100) of an inch in length. Its color now is a light yellowish
green and its eyes are pale reddish in color. No evidences of
wing pads are yet present. The abdomen is more robust than
at first. In other respects the nymph is unchanged (see fig.
21, e).
By the time the third stage is reached the nymph is about
seven-one-hundredth (7/100) of an inch in length. Its body
color is now a light yellowish green. Its eyes are unchanged. The
entire body is more robust than at any time previous. Wing
pads are developing as lateral buds which extend over the first
abdominal segment (see fig. 21, f). Spines are more pronounced
and the nymph is more active in its habits.
As the fourth stage is reached the nymph has become about
eight-one-hundredth (8/100) of an inch in length. The general
color is a yellowish green and the eyes are still whitish. The
wing pads extend to the second abdominal segment (see fig. 21,
g). The spines are very pronounced. It is more active in its
movements than ever before.
The fifth stage finds the nymph about one-tenth (1/10) of an
inch in length. Its head and thorax are light green in color and
the abdomen greenish yellow. Eyes are unchanged. Wing pads
have reached the fourth abdominal segment. The body is much














TABLE 3.-SHOWING NUMBER OF INSTARS, THEIR LENGTH, AND LENGTH OF NYMPHAL LIFE
SL Length
I nym-
Eggs 1st Length 2nd Length 3rd Length 4th Length 5th Length phal
Deposited Hatched Molt 1st Stage Molt 2nd Stage Molt 3rd Stage Molt 4th Stage Molt 5th Stageperiod
Sept. 2 Sept. 11 Sept. 14 3 Sept. 16 2 Sept. 20 4 Sept. 25 5 Sept. 29 4 18
Sept. 2 Sept. 10ept pt. 1ept. 1 pt. 15 3 Sept. 20 5 Sept. 24 4 Sept. 29 5 19
Sept. 2 Sept. 11 Sept. 14 3 Sept. 17 3 Sept. 21 4 Sept. 26 5 Sept. 30 4 19
Sept. 3 Sept. 12 Sept. 14 2 Sept. 17 3 Sept. 21 4 Sept. 25 4 Sept. 30 5 18
Sept. 3 Sept. 13 Sept. 16 3 Sept. 19 3 Sept. 23 5 Sept. 27 4 Oct. 1 4 19
Sept. 3 Sept. 12 Sept. 15 3 Sept. 19 4 Sept. 23 4 Sept. 28 5 Oct. 3 5 21
Sept. 5 Sept. 14 Sept. 16 2 Sept. 19 3 Sept. 22 3 Sept. 26 4 Oct. 1 5 17
Sept. 5 Sept. 15 Sept. 18 3 Sept. 22 '4 Sept. 25 3 Sept. 30 5 Oct. 4 4 19
Sept. 6 Sept. 14 Sept. 16 2 Sept. 19 3 Sept. 23 4 Sept. 27 4 Oct. 3 6 19
Sept. 6 Sept. 15 Sept. 18 3 Sept. 21 3 Sept. 25 4 Sept. 30 5 Oct. 5 5 20
Sept. 6 Sept. 16 Sept. 19 3 Sept. 23 4 Sept. 27 4 Oct. 2 5 Oct. 6 4 20
Sept. 8 Sept. 17 Sept. 19 2 Sept. 23 4 Sept. 26 3 Oct. 1 5 Oct. 6 5 19
Sept. 9 Sept. 18 Sept. 20 2 Sept. 23 3 Sept. 28 5 Oct. 2 4 Oct. 7 5 19
Sept. 10 Sept. 19 Sept. 22 3 Sept. 25 3 Sept. 29 4 Oct. 3 4 Oct. 7 4 18
Sept. 10 Sept. 20 Sept. 24 4 Sept. 27 3 Oct. 1 4 Oct. 4 3 Oct. 10 6 20
Sept. 10 Sept. 19 Sept. 21 2 Sept. 26 5 Sept. 29 3 Oct. 3 4 Oct. 7 4 18
Sept. 12 Sept. 21 Sept. 23 2 Sept. 27 4 Oct. 1 4 Oct. 6 5 Oct. 11 5 20
Sept. 12 Sept. 22 Sept. 26 4 Sept. 29 3 Oct. 3 4 Oct. 7 4 Oct. 12 5 20
Sept. 12 Sept. 21 Sept. 24 3 Sept. 27 3 Sept. 30 3 Oct. 4 4 Oct. 8 4 17







Bulletin 164, The Bean Leaf-Hopper 73

more robust than at any of the previous stages. The general
shape now is similar to that of the adult (see fig. 21, h). The
insect is unusually active and can hop from one plant to another.
Activity-Only the adult bean leaf-hopper can fly. The
nymphs have only rudimentary wings and their movements con-
sist merely of a hop and a sidewise run. The insects, both adults
and nymphs, are most active from late in the morning until early
in the evening.
In the presence of a strong wind the adults fly with the wind
and rise only a few feet. Usually they fly only to adjoining
plants. When there is little wind and they are released, they
fly straight up into the air for fifteen or twenty feet, usually in
the direction toward which the wind is blowing. The influence
of weather is quite noticeable upon their flight; they are most
active at a temperature of 70" to 90' F. Below 70 they are
inactive. Neither are they active in wet weather.

LIFE HISTORY
These studies of the bean leaf-hopper were conducted on more
than fifty varieties of bush, pole, lima, pea and castor beans as
well as on Irish potatoes and sweet potatoes.
The outdoor laboratory (see fig. 14) in which these experi-
ments were carried on possessed conditions as nearly normal as
it was possible to have them and at the same time carry on
the experiments successfully. But the summer months were
unusually hot and dry and the number of insects that died was
extremely high.
The most serviceable rearing cages found for studying the
egg stage, the nymphal instars (the molting period), the life
of the adults, and the manner and extent of reproduction, are
one- and two-inch glass cylinders with sealed-cloth tops and
cork bases. These were ventilated by perforations in the sides
of the cork bases. In the cages were large vials which con-
tained water and food for the insects.
Age Attained by the Insects.-The life of the individual adult
in these experiments ranged from 14 to 92 days. The females
averaged 64 days while the males averaged 48 days. Thus the
females seem to live longer than the males.
How the Insect Passes the Winter.-In the experiments upon
which this bulletin is based the females stopped laying eggs
after December 15. A large number were placed in cages, both







74 Florida Agricultural Experiment Station

TABLE 4.-SHOWING THE LENGTH OF TIME LIVED BY SEVERAL INSECTS
MALE FEMALE
Days I Days
No. Emerged Died lived No. Emerged Died lived
2 March 13 April 20 38 2 Maich 21 June 6 77
3 May 10 May 24 14 3 May 10 July 25 76
4 June 16 July 13 27 4 May 14 July 25 72
5 Aug. 12 Sept. 2 30 8 May 22 June 20 29
6 Aug. 12 Oct. 7 68 5 Sept. 8 Nov. 15 68
7 Oct. 11 Dec. 22 72 6 Sept. 9 Nov. 13 65
8 Oct. 11 Dec. 2 52 7 Sept. 12 Oct. 15 33
1 Oct. 28 Jan. 17 81 1 Oct. 28 Feb. 27 92
Average, \ 48 II Average, 64

indoors and outdoors. In this way some success was experienced
in getting a few individuals to live thru the winter. These were
more or less active late in February, and even as late as March
2, 1922, some were found active and there were evidences of
egg scars on the plants.
In the latitude of Gainesville in 1921 the bean leaf-hopper
was most abundant during the latter part of August, all of
September and the first part of October. The greatest mortality
during this season was late in December, very few individuals
being found after this period. It was observed that most of the
deaths were due to cold weather. The individuals still living at
this time sought shelter under those host plants protected by
trees, fence corners and other things. Here they have been found
to hibernate (live thru the winter) until the plants again become
green. The castor bean, shown in figure 15, has proven a fav-
orite hibernating spot of the bean leaf-hopper. Where the in-
sects live over winter, they deposit eggs early in the spring,
unless they meet with some serious accident.
Appearance in Spring and Number of Generations.-The
adults of the bean leaf-hopper have been found active in the
latitude of Gainesville as early as March 1. Their early appear-
ance depends very much on the season, however, and the best
index of the appearance in spring is the renewed growth of their
host plants.
As said above adults have been seen stirring and depositing
eggs at this early date and, in order to show that the eggs were
fertile, the insects (female) were removed from the plants after
12 hours; and the eggs hatched. In the outdoor cage experi-
ments eggs were recorded from March until December. From
five to six generations were reared in the experimental laboratory










DIAGRAM INDICATING NUMBER OF GENERATIONS RAISED IN THE EXPERIMENTAL LABORATORY IN 1921

Jan. Feb. Mar. April May June July Aug. Sept. Oct. Nov. Dec.

Hibernating adults


1st Gen. -.


2nd Gen.

S.I
3rd Gen.


4th Gen.


5th Gen.


6th Gen.




v1






76 Florida Agricultural Experiment Station
in Gainesville, the first generation hatching March 11, 1921. This
generation lived until May 2. The second generation lived from
May 2 to June 20, the third from June 20 to August 5, the























I

Fig. 22.-Earliest symptoms of tipburn, or hopperburn, on a healthy bean
plant






Bulletin 164, The Bean Leaf-Hopper 77

fourth from August 5 to September 30, the fifth from Septem-
ber 30 to November 28, and the sixth from November 28 to
February 27, 1922.
CHARACTER OF INJURY
The plants are injured directly by the loss of juices extracted
from the leaves by the leaf-hoppers thru their sucking mouth
parts. The tender surfaces of the leaves and stems are pene-
trated, and as a result of the loss of juices the plants take on a
yellowish appearance. The next injury to appear is called "tip-
burn" or "hopperburn"2 which starts with a slight yellowing,
often at the tip of the leaf, and as the injury progresses along
the margin of the leaf the color turns to a dark brown and the
leaf begins to curl upward at its apex (see fig. 22). The leaf
then soon withers and dries up and, if the infestation is heavy,
even falls off.
The disease spreads from the apex or margin toward the mid-
rib of the leaf, increasing more slowly along the basal portion,
which sometimes retains patches of green. In such cases the
margin of the leaf presents a ragged appearance (see fig. 23).
Besides the injury done the leaves, the plant's growth is re-
tarded and, if the outbreak proves serious, little or no fruit will
be produced. However, if the insect is controlled during the
early life of the plants, the crop is most likely to be a good one.
EFFECT ON DIFFERENT VARIETIES OF BEANS
Different varieties of beans were tested out in the field with
the purpose of finding a variety suited to Florida conditions and
at the same time more or less resistant to the injuries of the
bean leaf-hopper. Experiments were carried out with some 60
varieties and it was found that all were affected, some, of
course, more than others. Some of the pea-bean varieties showed
a marked degree of resistance (Wells Red Kidney, for instance).
The bush lima indicated a slight degree of resistance. The pole
bean varieties proved least resistant to the hoppers' attacks,
while the snap bean came next to the pole bean in its suscepti-
bility. METHODS OF FEEDING
The lower leaves on the young plants usually are attacked
first, and as the female leaf-hopper attacks the young plant she
deposits eggs in the leaves. The eggs hatch out after a lapse
of about ten days. By this time the plant has developed con-
""The Potato Leaf-Hopper and the Hopperburn that it Causes," by
E. D. Ball in Bul. 20, Wis. Dept. of Agri., 1918, pp. 76-100.







78 Florida Agricultural Experiment Station

siderable new growth. But the young nymphs, as they hatch,
usually start feeding on the leaves where they hatch.
The bean leaf-hopper usually feeds on the large veins of the
leaf, and may be seen in a horizontal position on the lower side
of the leaf. The sharp point of the proboscis (snout, or beak),
suspended from the lower side of the body, is forced thru the
epidermis of the leaf. It is in this way that food or sap is
taken into the insect's body. Several instars, or molting periods,
have been found to take place on a single leaf. The feeding
habits of all stages of the bean leaf-hopper are known to be
identical.
The writer executed a unique experiment in testing out the
insect's choice of food materials. Several different stages of
nymphs were placed on the arm and soon piercing sensations
from the sharp proboscis were experienced. The insect fre-
quently selected a new place, continuing for about thirty min-
utes in its vain endeavor to find suitable food.
DISTINCT INJURY BY BEAN LEAF-HOPPER
In addition to injuring the bean plant by sucking out its
juices, the leaf-hopper is responsible also for a distinct injury
called "hopperburn," mentioned above. This injury most fre-
quently starts with a slight yellowing and turning up of the leaf
(see fig. 22). The yellowing and curling usually begins at the
apex of the leaf, spreads along the margin until the entire
margin is affected, and then works inward toward the base of
the leaf. The diseased portion appears burned and slowly turns
to a Vandyke, or deep, brown color and curls Upward (see fig.
23). Ordinarily a small patch along the mid-vein remains un-
affected. But in serious infestations this area, as well as the
mid-vein, is destroyed and the entire leaf appears dried and
burned (see fig. 19). Other things being equal, hopperburn
seems to progress most rapidly during periods of hot dry
weather, according to our field experiments in the summer and
fall of 1921.
Relation of the Bean Leaf-Hopper to Hopperburn.-Since tip-
burn has been recorded for a number of years to designate any
burning of the leaves, it was thought originally that this trouble
was caused by rapid transpiration due to abnormal fluctuations
of temperature and moisture. Later, Dr. L. R. Jones suggested
that insects might be a factor in causing tipburn, thus giving
rise to the name "hopperburn."
To determine the part the bean leaf-hopper plays, if any, in








Bulletin 164, The Bean Leaf-Hopper 79








































Fig. 23.-Tipburn, or hopperburn, typically developed on the lower leaves
of a bean plant; the basal part of the leaf is still green
causing hopperburn, investigations were conducted in the snap-
bean growing sections of the state. Observations, without ex-
ception, showed that wherever the injury is found, there also
is found the bean leaf-hopper or its cast-off skin. And, on the
other hand, it was found that wherever no bean leaf-hoppers
are found, there also is found no hopperburn. The following
experiments bear out these observations and conclusions.








80 Florida Agricultural Experiment Station

Into a few rearing cages containing bean plants were intro-
duced a number of aphids, Myzus persicae, which occurred
abundantly on the bean plants in the field. The injury caused
by these aphids in no way resembled hopperburn. Similar ex-
periments were conducted with the red spider, Tetranychus
bimaculatus, which frequently are found in the bean fields. And
again the injury did not resemble hopperburn.
Proof that Bean Leaf-Hopper Causes Hopperburn.-A series
of experiments were conducted in the greenhouse to prove that
the bean leaf-hopper is the direct cause of hopperburn on beans,
and also to find what effect the different nymphal stages may
have on the foliage.
In the first experiment, one first-stage nymph was placed on
the lower side of a young bean leaf and covered with a veteri-
nary capsule, the sides and top of which were perforated with
small holes to provide ventilation. A light rubber band placed
about the leaf held the capsule in place. A piece of stiff card-
board was placed between the rubber band and the leaf to keep
the latter in its natural position. Ropperburn symptoms were
found to develop in from five to ten days on those leaves with
which the leaf-hopper had been confined. Usually no hopper-
burn appeared until the insects reached their third or fourth
nymphal stage. Therefore, it is apparent that the amount of
injury, and very largely the injury itself, depends upon the
age of the nymph. In other experiments where insects older
than those used in the first experiment were confined with the
leaves, the hopperburn developed much more rapidly.
In another group of experiments nymphs, advanced to the
fourth and fifth instars (or molting periods), respectively, were
introduced on separate bean leaflets to determine the effects
of the different stages in developing hopperburn. The results
indicate that the fourth instar nymphs produced hopperburn
in from one to six days. Yet the nymphs had advanced to the
fifth instar before the injury became noticeable. From these
and other experiments it seems that the bean leaf-hopper reaches
its fourth or fifth instar before burning symptoms are notice-
able, that is, such symptoms as usually are produced on a nor-
mal leaflet in 24 to 48 hours.
A series of experiments, similar to the foregoing ones, were
conducted with both nymphs and adults, the results of which
show that the burning develops more quickly in its spread over
the individual leaflets.








Bulletin 164, The Bean Leaf-Hopper 81

In summarizing the results of experiments it is evident that
the presence of bean leaf-hoppers is a positive indication that
the bean leaves will be affected by the typical burning and roll-
ing. This trouble is identical with that which Dr. Ball described
as occurring on potatoes. It may be produced on beans in sev-
eral days and has been found to destroy them in a few weeks.
Other evidence which shows that this insect is the cause of
the burning, is the cast-off skins and egg scars.
Different soils seemed to have little effect upon the develop-
ment of burning. Wet weather appeared to check it, while dry
weather seemed to favor its growth.
NATURAL ENEMIES
It has been observed that this species is preyed upon in Flor-
ida by few natural enemies. Several species of spiders occa-
sionally have been found entangling an adult or nymph in their
web, and a species of mite has been seen feeding on the nymphs.
The common small red ant, Dorymyrmex pyramicus (Roger,
subsp. flavus, McCook), has been noticed frequently preying
upon the several nymphal
stages.
The parasitic fungi En-
tomophthora sphaerosperma,
Fresenius, was found attack-
ing the adults and all stages
of the nymphs in July, Au-
gust; September and October. 0.
When this fungous disease is
contracted the insect victims
seem to die within a few days.
Diseased adults are charac-
terized by outstretched wings
(fig. 24). Thread-like
growths, which are character-
istic of the fungus, practi-
cally cover the insect's body,
seeming to have a particular
preference for the looser and
softer portions of the body.
After death, the leaf-hopper
turns to a pale yellowish tint,
while the fungous growth, or Fig. 24.-Mature bean leaf-hopper
mat, becomes flattened on the killed by a fungus








82 Florida Agricultural Experiment Station

upper surface, assuming a color varying from white to a pale
greenish blue.
For the most successful incubation, development and dissemi-
nation of this disease, warm, moist weather is necessary.

CONTROLLING THE BEAN LEAF-HOPPER
The control of the bean leaf-hopper and the prevention of hop-
perburn, is made most difficult by the wide range of food plants
upon which this species feeds. Hence, rotation is out of the
question and clean culture is of little value as means of con-
trolling the leaf-hopper, except that the alternating host plants
are destroyed by these systems. Spraying is the only method
found successful in controlling the bean leaf-hopper and pre-
venting hopperburn.
The results of last year's control experiments show that
spraying with bordeaux mixture, if done thoroly, will repel the
leaf-hopper and control hopperburn. Bordeaux mixture com-
bined with nicotine sulphate acts much more rapidly in ridding
the plants of leaf-hoppers than bordeaux alone. The increased
effectiveness obtained by adding nicotine sulphate, justifies the
extra expense. (See table 5.)
Nicotine sulphate and soap in a combined form have been used
and found very effective in killing the hoppers, both the adults
and nymphs. However, this treatment did little good, as the
plants soon became infested again and hopperburn was not con-
trolled at all. (See table 5.)
Kerosene emulsion was found to be a little less effective than
nicotine sulphate and soap in killing the adult leaf-hoppers and
nymphs. However, hopperburn appeared to be worse following
this spray than where the other sprays were used. (See table 5.)
Directions for the Preparation of Bordeaux Mixture of for-
mula 4-4-50 (which is sufficiently strong to control the bean leaf-
hopper) follow:
Barrel No. 1 Barrel No. 2

Rock lime, unslaked -4 lbs. rsulphate) -4 vbs
(copper sulphate) -4 lbs.
Water -25 gals. Water -25 gals.
First slacK the lime and then add Place blue vitriol in bag and sus-
the rest of the water. pend in the water until all is
dissolved.
CAUTION CAUTION
Do not use air slacked lime Do not use metal container








Bulletin 164, The Bean Leaf-Hopper 83


Barrel No. 3
When read to spray, pour solutions from Barrel No. 1 and Bar-
rel No. 2 into Barrel No. 3. Mix thoroly. This will form a dark
bluish liquid. Strain thru heavy gauze before pouring in the sprayer
tank.

Because of the dry season six sprayings were applied at in-
tervals of about a week. The spraying was done at a pressure
of 200 pounds. After summing up the results it was found that
nicotine sulphate and whale-oil soap gave best results in killing
the insects, and that bordeaux mixture and nicotine sulphate
gave best results in controlling and preventing hopperburn.
TABLE 5.-SHOWING SUMMARY OF RESULTS OF EXPERIMENTS WITH A NEW
DESIGN SPRAYER AND THE RELATIVE VALUE OF DIFFERENT TESTED FOR-
MULAS FOR THE BEAN LEAF-HOPPER AND TIPBURN.
Adults & Control
Earliest nymphs of
date 100 killed, tipburn,
Plot Spray material Dilution applied pl'nts percent percent
___Check plot, __________________ ______
1 Unsprayed _|_|
2 Nicotine sulphate 1-1000 Sept. 15 0 90 75
__ (40%)
Nicotine sulphate
3 (40%) & whale- 1-1000 Sept. 15 95 89
oil soap, 1 lb. O
4 Whale-oil soap 10 gals. Sept. 15 0 7 70
water 1 lb.
5 Bordeaux mixture 4-4-50 | Sept. 15 | 0 42 95
Bordeaux mixture 4-4-50
6 and Sept. 15 0 85 95
nicotine sulphate 1-800
7 Kerosene emulsion 7% Sept. 15 0 | 81 | 60

Method of Applying and Importance of Spray.-Since the leaf-
hopper was observed to attack only the lower side of the leaves,
it would seem that only this surface requires spraying. But
often it was noticed that where the upper side of the leaves was
not sprayed, the nymphs and the adults, if they did not take
flight when molested, would assume sidewise running move-
ments and, in quest of protection, pass over the edge of the leaf
to the upper side. When the danger was over, these individuals
were found seeking suitable feeding places which had not been
reached by the spray.
Another important point observed was the time to begin
spraying, as, in case of an outbreak, the leaf-hoppers colonize on
the plants as soon as the first leaves are formed. For this







84 Florida Agricultural Experiment Station

reason, spraying should commence as soon as the first foliage is
well formed. In the course of these experiments it was realized
that efficient apparatus is necessary for the proper application
of the spray. After experimenting with all available equip-
ment, it was found that best results were accomplished by using
the apparatus described below and which was designed by the
writer himself.
This New Spraying Device contains three wide-angle mist-spray
nozzles, all of which are connected to a common hose attached
to a pressure pump and sprayer tank (figs. 25, 26, 27, 28).





















constructed to pass over the beans
The nozzles are inclosed within a canvas-covered cylinder which
is at least 36 inches in length and 24 inches in diameter. The
ends of this cylinder are closed except for notch-like openings,
about 8 inches in diameter, at either end. This opening points
downward to permit the cylinder's being passed over the plants
(fig. 25). A wide-angle mist nozzle, located in top of this
cylinder and about the middle, directs the spray downward on
top of the foliage. Two wide-angle mist nozzles, located on
either side of the 8-inch opening and midway between the ends
of the cylinder, are adjusted to direct the spray either inward
among the plants or upward. The three nozzles thereby make







Bulletin 164, The Bean Leaf-Hopper 85
















Fig. 26.-Another view of the new spraying device

it possible for the spray to come thoroly in contact with the
lower side of the foliage. The openings in the ends of the
cylinder are regulated by means of a cord, which makes it pos-
sible to increase or decrease the size of the openings, according
to the size of the plants (fig. 25).
Some Advantages of This New Spraying Device, as worked
out by our experiments, are as follows:
1. It prevents the escape of insects when spray is applied to
the plants.
2. To prevent their escape means their being killed by direct
contact with the spray or by suffocation from the fumes of the
combined nicotine and whale-oil soap.
3. A thoro application of spray may be applied to the smallest
plants, because two nozzles are adjacent to the ground. It is
an important factor in autumn control work, since the leaf-
hoppers colonize soon after the first leaves are formed.
4. By holding or confining the spray material close to the
plants, the greatest efficiency and economy is secured by spray,
vapor and fumes.
5. This spraying device can be operated successfully as fast
as a horse usually walks. An acre has been sprayed in one
hour. With sufficient power the sprayer can be operated by
one man.








86 Florida Agricultural Experiment Station

SCIENTIFIC NAME AND HISTORY OF THE BEAN LEAF-
HOPPER
The bean leaf-hopper was first mentioned and described by
LeBaron' about 1853 under the name Tettigonia mali. He re-
corded it as injuring fruit trees in Illinois. In 1862 Walsh'
erected the genus Empoasca with three new species, among
which mali was not mentioned. Carlos Berg" in 1879, described
a jassid, Typhlocyba phytophila, received from Argentina, but
later this was found by Gillette to be a synonym of Empoasca
























Fig. 27.-Arrangement of nozzles. The upper one passes over the plants,
while the lower ones pass on either side of the plants

mali. Forbes in 1883' sent specimens of a green apple leaf-
hopper to Uhler, who identified them as belonging to the genus
Empoa. Subsequently these insects were described by Forbes'
"LeBaron, L., 1853: "Observation Upon Two Species of Insects Injur-
ious to Fruit Trees," in the "Prairie Farmer," pp. 330-331.
"Walsh, B. D., 1862: "Entomological Notes," in the "Prairie Farmer,"
pp. 148-149.
"Berg, C., 1879: Hemiptera Argentina; Enumeravit Speciesque Novas,
p. 273.
"Forbes, S. A., 1883: "The Green Apple Hopper," in 13th Rpt. Ill. Ent.
Soc., pp. 181-183.
7Forbes, S. A., 1886: Proceedings of the Entomological Club of the
A. A. A. S., in the "Entomological American."








Bulletin 164, The Bean Leaf-Hopper 87

as belonging to a new species, Empoa albopicta. Woodworth8
in 1889 changed Empoa albopicta Forbes to the genus Empoasca
and called it Empoasca albopicta. In 1890 Gillette" made the
first reference to this species under its correct name, Empoasca
mali. Osborn'" in 1896 mentioned it as injuring potatoes and
Gibson" in 1909 found it on the same host. In 1898 Gil-
lette" gave a list of its host plants and distribution.
Among the names common in entomological literature this
jassid (the bean leaf-hopper) is referred to as "apple
leaf-hopper" and "currant leaf-hopper" by Britton," Brues"



$ /









Fig. 28.-The spraying apparatus is applicable to small or extensive plant-
ings. Here it is shown operated by high power and hauled in a wagon

and Garman." Other writers frequently refer to it as the most
injurious leaf-hopper on apples and various field crops. Wash-
burn" was the earliest writer to publish (1908) a record of
the biology, food plants, injury and control of the apple leaf-
hopper as a nursery pest in Minnesota. Later Webster" (in

"Woodworth, C. P., 1889: "North American Typhlocybini," in Psyche,
V. 5, pp. 211-214.
"Gillette, C. P., 1890: "A Few Injurious Insects and Their Remedies,"
in Trans. Iowa Hort. Soc., V. 25, pp. 102-106.
"Osborn, H., 1896: "A New Pest of Potatoes," in Iowa Agri. Col.
Exp. Sta. Bul: 33, pp. 603-605.
"Gibson, A., 1909: "Insects of the Year at Ottawa," in 39th Rept.
Ont. Ent. Soc., pp. 116-120.
"1Gillette, C. P., 1898: "American Leaf-Hopper of Subfamily Typhlo-
cybinae," in Proc. U. S. Nat. Mus., V. 20, No. 1138.
"1Britton, W. E., 1905: "The Apple or Currant Leaf-Hopper, Em-
poasca mali, LeB.", in 4th Rpt. Sta. Com. 1904, p. 216.
"Brues, C., 1905: Report of the State Nursery Inspection, in 22nd An.
Rpt. Agri. Exp. Sta., Uni. of Wis., pp. 322-329.
"."Garman, H., 1908: "Spraying Apple Trees," in Ky. Agri. Exp. Sta.
Bul. 133.
"'Washburn, F. L., 19C8: "Two Years Work With the Apple Leaf-
Hopper," in Minn. Agri. Exp. Sta. Bul. 112, pp. 145-164.
"Webster, R. L., 1910: "The Apple Leaf-Hopper," in Iowa Agri. Exp.
Sta. Bul. 111.







88 Florida Agricultural Experiment Station

1910) made a thoro study of the biology and control of this in-
sect on apple nursery stock in Iowa, and in 1915" he described
Empoasca mali as a pest of potatoes. Dr. Ball" published a
treatise on "The Potato Leaf-Hopper and Its Relation to Hop-
perburn."
The next writer was Ackerman'2 who the same year published
an account of this leaf-hopper's depredation to nursery stock in
Pennsylvania. In 1921 Dudley" published an article on the
potato leaf-hopper and its control in Wisconsin, and the same
year Dudley and Wilson22 prepared a popular paper on "Combat
Potato Leaf-Hopper with Bordeaux."
E. MALI
The synonymy of E. mali as understood now is as follows:
Tettigonia mali (LeBaron), 1853.
Empoasca (3 sp., no mali) (Walsh), 1862.
Typhbocyba phytophila (Berg), 1879.
Empoa (Uhler), 1883.
Empoa albopicta (Forbes), 1883.
Empoasca albopicta (Woodworth), 1889.
Empoasca mali (Gillette), 1890.
"Webster, R. L., 1915: "Potato Insects," in Iowa Agri. Exp. Sta.
Bul. 155.
"Ball, E. D., 1919: "The Potato Leaf-Hopper and Its Relation to the
Hopperburn," in "Journal of Economic Entomology," Vol. 12, No. 7, pp.
149-155.
"Ackerman, A. J., 1919: "Two Leaf-Hoppers Injurious to Apple Nur-
sery Stock," Bul. No. 805, U. S. D. A. (a professional paper).
"2Dudley, J. E., 1921: "The Potato Leaf-Hopper and Its Control," in
Farmers' Bul. 1225, U. S. D. A.
"'Dudley, J. E. and Wilson, H. F., 1921: "Combat Potato Leaf-Hopper
With Bordeaux."
ACKNOWLEDGMENTS
The writer wishes here to express his appreciation to Prof.
J. R. Watson and Dr. O. F. Burger, both of the Florida Experi-
ment Station, for making it possible for him to study the insect
pest discussed herein. He is further indebted to Prof. Watson
for identification of predacious thrips, and to Mr. T. Van
Hyning for supplying reference literature from the Congres-
sional Library. Thanks also are due Dr. W. M. Wheeler for
determination of predacious ants, to Dr. Roland Thaxter for
identification of the parasitic fungi, Entomophthora spaero-
sperma, Fresenius, and to Dr. Wilbur Brotherton, of the Bureau
of Plant Industry, United States Department of Agriculture,
for assistance in making bean variety selections.





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