LEAFLET 46
MARCH 1955
LEAF SPOT aa STRAWBERRY
WEEVIL amIRAILING BLACKBERRIES
U. L. DIENER, Asst. Plant Pathologist
W. G. EDEN, Entomologist
C. C. CARLTON, Superintend'ent, Chiton
Area H'-orticultural Substation
111 I (5 \Ni[ illIA-L Pii(DUCT(1iO (f
ti ailiiw blackberiries (Y ouian od Bo-lo
Sell \SLl'iV tics) lois liccit of, horticuiltul i
110 Port in it'li cei itrIa] Alabioii I fori si',
ci dl vearis. Ini 1940, thie estjiiiiitd \ ahic
of the Hickbeil x vi Cop ill (h1iltonl Coinl
t\ was S I 4.)0W; ill 1954. it \\ as $250,-
000, aii ad', ge of Ox rl $400) per acre.
1'ruinl all iniictiois this iiidusti' xill
Dijseases aniid insects are two ofti the
hinlitiuif fatoic is ini the pr oduictioni of'
hbl iCkbl~iC. i .Leaf spot is the io~st in
}mnrtiit dise'ase, aind the straxibcirr wee'--
vil is the mrajor insect pest oif the: Crop.
Expcriiiuents onl contiro1 of leaf spot andi
straxx leirx \x c', iili' haeie conuiitcc
fori thc past 3x i vas it the Chijltoni Aica
I liticiiltiiial Silibstatiii ilear Claitiin.
R esults of thiese expei ncut, ad re
iiniiiatjiiis foi the cootio of u the
pe(sts dir reiporiitedl ill this leaflet.
BLACKBERRY LEAF SPOT
Symptoms and Development
''1 iiwr hi Iicikberii c' inl Alabania aic
frieiqiii tl affected I\ ai leaf spot (115
Cadse, CaiSedt bV tile tongoTs SC'pto; iO
rti/u West. I-])(- tiiieiiis (i tlsi s (,\tell-
AGRICULTURAL EXPERIMENT STATION
ogihe ALABAMA POLYTECHNIC INSTITUTE
E. V. Smith, Director
Auburn, Alabama
TABLE 1. CONTROL OF LEAF SPOT OF TRAILING BLACKBERRIES WITH FUNGICIDAL SPRAYS
AT CLANTON, ALABAMA, 1952-53-54
Average number of lesions
Treatment 
per leaflet
19521 1958 1954
Untreated check 47.6 127.4 25.8
Ferbam (Fermate), 11 lb. per 100 gal. 9.2 54.8 5.5
Captan (Orthocide), 2 lb. per 100 gal. 17.1 56.9 4.5
Maneb (Manzate), 2 lb. per 100 gal. 20.1 56.6 2.8
Captan (2 lb.) + Ortho Leaf Feed (1 lb.) per 100 gal. 48.3 4.5
LSD, 1% 18.2 30.9 9.7
1 Tribasic copper sulfate, nabam, and Dow F-1003 all caused injury in 1952.
sive spotting of the leaves as well as
inconspicuous lesions on the leaf stalk
and occasionally on the canes. Leaf
spot first appears as minute purple
specks, which enlarge to irregular pur-
ple-brown spots 
about 1/8 inch in 
diam-
eter. Older spots are more circular in
outline with light-brown to tan centers
surrounded by a zone of purple tissue.
The centers of old spots are gray to
white with brown or reddish borders.
Small black dots, the fruiting bodies
(pycnidia) (of the fungus, can be seen
in these gray-white centers.
The fungus overwinters in leaves or
in the bark of the leaf stalks and canes.
The fruiting bodies produce hundreds
of microscopic needle-shaped spores,
each of which can cause another leaf
spot. Under high moisture conditions
in early spring, spores are discharged
from the fruiting bodies. They are
spread by insects and splashing rain to
the leaves, where they cause infection.
Blackberry leaves may become heavily
spotted, turn yellow to red-brown, and
die. Although the leaf spot disease of
blackberries has not caused extensive
damage in the last 3 years, it may re-
sult in serious damage by defoliation
in wet years.
Experimental Results
During the past 3 years, leaf spot
was controlled in Alabama with several
fungicidal spray materials. Fungicides
were combined with DDT insecticide
for strawberry weevil control. Sprays
were applied with a hand boom con-
nected to a small power sprayer 
op-
erated at 250 to 300 pounds pressure
to wet the foliage thoroughly at each
application.
Shortly after the canes were hung on
a barbed-wire trellis in late winter, a
delayed dormant spray of liquid lime-
sulfur (1-10) was applied to kill the
fungus overwintering on the canes.
Foliage fungicides were applied at 7- to
14-day intervals after the first leaves
were well developed for at least 3 ap-
plications before harvest. Three years'
results .of the experiments, 1952-54, are
given in Table 1. The concentrations
of the spray materials are also recorded
in this summary. Ferbam (Fermate,
Nu Leaf), maneb (Manzate, Dithane
M-22) and captan (Orthocide, Stauf-
fer) were very effective in reducing
leaf spot damage.
STRAWBERRY WEEVIL
Life History and Damage
The strawberry weevil, 
Anthonomus
signatus Say, is a small, dark reddish-
brown snout beetle from 1/12 to 1/8
inch long. It looks very much like the
boll weevil but is considerably smaller.
The adult weevils become active early
in the spring about the time blackber-
ries and strawberries are coming into
bloom. The female weevil makes a
puncture in the blackberry bud with
her long beak and lays an egg in the
puncture. She then crawls down and
girdles the stem of the bud. The eggs
hatch into small, white, soft-bodied
grubs that have no legs. The grubs
feed inside the bud and after about
4 weeks they change to the pupal
stage within the bud. The new brood
of adults emerges shortly before mid-
summer. The newly emerged adults
feed for a short time and then go into
hibernation under trash in the field,
where they remain until the following
spring.
The bud in which the egg is laid and
of which the stem is girdled never
opens. Severe weevil infestations may
drastically reduce the yield of black-
berries. Yield reductions of 25 per cent
due to this insect are common in the
Chilton berry-growing area.
Experiments on Control
Experiments were conducted in 1952,
1953, and 1954 on control of the straw-
berry weevil with insecticidal sprays.
Wettable powder formulations of DDT,
chlordane, and toxaphene were used.
The amounts of materials per 100 gal-
lons of water were as follows: DDT, 2
pounds of 50 per cent wettable; chlor-
dane, 2 pounds of 50 per cent wettable;
and toxaphene, 5 pounds of 40 per cent
wettable powder. Ferbam, 2 pounds of
76 per cent wettable per 100 gallons of
spray, was used for disease control on
all plots including the check. Spray ap-
plications were made with a 3-nozzle
hand boom connected by a 100-foot
hose to a power sprayer. The sprays
were applied at 390 pounds pressure in
sufficient quantity to wet the foliage.
Three insecticidal applications were
made each year. Spraying was started
when the vines began to produce buds
freely. Intervals between sprays were
from 1 to 2 weeks, depending on the
rate of bud production. The interval
between the last application of spray
and the first picking of ripe berries was
from 3 to 4 weeks.
The results of the 3-year experiment
are presented in Table 2. Toxaphene,
DDT, and chlordane were all effective
in controlling the weevil with conse-
quent increases in berry yields. Toxa-
phene was the most effective; DDT was
intermediate; and chlordane was the
least effective of the three insecticides.
SUMMARY
1. Leaf spot is the most important
foliage disease of blackberries in Ala-
bama.
2. Experimental results of the past 3
years shows that leaf spot can be ef-
fectively controlled by a fungicidal pro-
gram consisting of a dormant spray of
lime-sulfur (1-10) and about 3 appli-
cations of a foliage fungicide (ferbam,
maneb, or captan) at 7- to 14-day in-
tervals after leaf development before
harvest.
3. To control leaf spot, recommend-
TABLE 2. YIELD OF BLACKBERRIES FOLLOWING SPRAYS FOR CONTROL OF THE STRAWBERRY
WEEVIL AT CLANTON, ALABAMA, 1952-53-54
Treatment
1  
Yields in pounds per acre
1952 1953 1954 3-year average
Untreated check 8,149 7,931 11,967 9,349
Chlordane, 2 lb. 50% 9,435 8,040 12,828 10,101
DDT, 2 lb. 50% 9,851 9,341 13,589 10,927
Toxaphene, 5 lb. 40% 10,028 9,735 13,733 11,165
LSD, 5% .... 498
1 Indicated amounts of insecticides were used as wettable powders per 100 gallons of
water. ,All plots, including the untreated check, received a fungicide for disease control.
ed rates per 100 gallons of spray are:
ferbam, 11/2 pounds of 76 per cent;
captan, 2 pounds of 50 per cent; maneb,
2 pounds of 70 per cent.
4. The strawberry weevil is the most
important insect pest of blackberries.
It may reduce. the yield as much as 25
per cent.
5. Experiments have been conducted
for 3 years on control of the strawberry
weevil with wettable powder sprays of
toxaphene, DDT, and chlordane.
6. Toxaphene and DDT were more
effective than chlordane.
7. Three applications of toxaphene or
DDT sprays at 7- to 14-day intervals
SPRAY MATERIALS TO MAKE 100 TI
GALLONS OF SPRAY
during the budding period resulted in
an increase in berry yields of from 1,500
to 1,800 pounds per acre.
8. Recommended insecticides and
rates are 2 pounds of 50 per cent DDT
or 5 pounds of 40 per cent toxaphene
per 100 gallons of spray.
9. It is recommended that a fungi-
dide-insecticide combination be used for
the most effective control of the black-
berry pests. Ferbam, captan, or maneb
may be used in combination with either
toxaphene or DDT.
10. Based on the foregoing results,
the following procedure should prove
effective in controlling the disease and
the weevil:
ME OF APPLICATION To CONTROL
10 gal. liquid
lime-sulfur
2 lb. 50% DDT or
5 lb. 40% toxaphene
and
1,/ lb. 76% ferbam
(Fermate, Nu Leaf)
I or
No. 2 N. 2 lb. 50% captan
(Orthocide, Stauffer's
Captan 50W)
or
2 lb. 70% maneb
(Manzate, Dithane M-22)
When vines are hung
on wires
When
(pear
first buds ap-
Overwintered disease-
fungus on canes
Strawberry weevil and
leaf spot
Additional applications of the No. 2 spray are made at 7- to 14-day intervals up to
2 weeks before harvest, depending on weather conditions.
No. 1