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Evaluation of different fungicides for the control of peach scab (Cladosporium Carpophilum), brown rot (Monilinia Fructicola), and Rhizopus Rot (Rhizo

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Title:
Evaluation of different fungicides for the control of peach scab (Cladosporium Carpophilum), brown rot (Monilinia Fructicola), and Rhizopus Rot (Rhizo
Creator:
Large, John R.
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Big Bend Horticultural Laboratory, University of Florida

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University of Florida
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145741568 ( OCLC )

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S'-7 BIG BEND HORTICULTURAL LABORATORY
MONTICELLO, Florida

Big Bend Hort. Lab. Mimeo Report BBL 67-9 April 20,1967

EVALUATION OF DIFFERENT FUNGICIDES FOR THE CONTROL OF PEACH SCAB
(CLADOSPORIUM CARPOPHILUM), BROWN ROT (HONILINIA FRUCTICOLA), AND
RHIZOPUS ROT RHIZOPUSS SP.), ON MAYGOLD PEACHES AT Mf -1 ,
IN 1966. R 8- V I
1
by J. L. Large.. L

INTRODUCTION

The production of peaches is a new but rapidly groinia.
The 1964 Dare report states that there are at least 4,000 acres now in young
and non-bearing trees. In 1966 Sharpe (Florida Grower and Rancher, August,
1966) estimated that around 3,500 acres have been planted in Central Florida,
North of the line extending from Brooksville to Sanford; and Young, 1966
(Mimeo Report BBL 66-4) estimated there were 3,953 acres in North Florida,
principally in Madison, Jefferson, Holmes, and Leon counties. With this rapid
growth in commercial production there is a need for research on timing of
applications and testing of fungicides for the control of the following leaf
and post harvest diseases;

1. Brown rot and blossom blight Monil&nia fructicola (Wint.) Honey.
2. Bacterial leaf spot Xanthomonas pruni (E.F.Sm) Dows.
3. Scab Cladosporiur carpophilum (Lev.) Aderh.
4. Rust Tranzschelia discolor (Fckl) Tranz & Litv.
5. Peach leaf curl Taphrinia deformans (Berk.) Tul.
6. Brown rot of fruit Monilinia fructicola (Wint.) Honey.
7. Grey Mold of fruit Rhizopus sps.

METHOD OF PROCEDURE

Maygold peach trees, planted in February 1964, were sprayed with eight
applications with a hand gun using dilute sprays applied at 450 P.S.I. The
first was a dormant spray of liquid lime sulphur, 5 gal/100 gallons of water
applied just before bud break (March 1). This spray was used in all treat-
ments except the unsprayed check. The dormant spray was followed by fungic-
ide and insecticide spray applications on March 22 (shuck split), April 5,
April 28, May'6, May 12, May 19, and May 24. Malathion 25WP, 3 lbs/100 was
used in dormant and first 3 cover sprays. Guthion 75W, 4 ozs/100 was used in .
the four May applications to control insects.

Ten fungicides with three one-tree replications of each treatment were
used. Botran 75W., 1.2 lb/100 was included in the last three sprays on half
of the trees. Leaf disease counts were made April 4, 19, and May 3rd. The
monthly rainfall was as follows; (1) arch 2.72 inches ;-Api-'L '. 99 6la-LJ
June 1 to 15, 5.72. HUME LIBRARY


b ,AY 3 9357
1 Associate Plant Pathologist

SIFA S. Univ. of Florida


200 cc


I I Ill II








-2-


FUNGICIDES TESTED

The fungicides tested were; Daconil: (2787) 2 lbs/100; Difolitan O0W,
1 Ib, and 1 1/2 lbs/100; Captan 50W, 2 lb/100; Cyprex + Captan 50W, 1/2 lb +
1 1/2 lbs/100; Kolofog, 6 lbs/100; Kolo-100, 6 lb/100; Sulphur, 6 lbs/100;
Polyram 80W, 2 lbs/100; Kocide, 6 lbs/100 (2 applications) then sulphur, 6
lbs/100; Dormant Lime-Sulphur 6 lb/100; and unsprayed trees. Botran 1.2 lbs/
100 was used on half the trees (3) of each treatment in the last 3 applicat- a
ions and for one treatment it was used in 7 applications with Difolitan 80W.

DISCUSSION OF LEAF DISEASES

Blossom blight, Peach leaf curl, bacterial spot, and rust were of minor
importance on sprayed foliage this season. Scab was serious (39% infection)
on unsprayed trees. No scab was found on trees sprayed with Captan 50W, 2
lbs/100, Captan + Botran, 2 lbs + 1.2 lbs/100, Polyram, 2 lbs/100, or Daco-
nil (2787) + Botran, 2 lbs + 1.2 lbs/100. Leaf counts made May 28 to May 30,
indicated that peach leaf curl, bacterial spot, and rust were of minor impo-
rtance on sprayed trees this season. (Table I).

Bacterial spot was most severe on leaves sprayed with Kocide 2 lb/100.
Two applications of this fungicide, which contains copper hydroxide, caused
yellowing and marginal necrosis of the foliage, with 30 to 50% defoliation.
These trees were sprayed with Sulphur 6 lb/100 in the last 6 applications.

CONTROL OF STORAGE DISEASES

Peaches, 30 per tree, (90 per spray treatment) were stored at room
temperature, 70 to 80 degrees F., for 4 and 7 days.

The percentage disease infection after 4 and 7 days are recorded in r
Table II.

The disease infection on the fruit was very light and generally less
than 5 per cent, after 4 days storage at room temperature. The best disease
control after 4 days storage, 100 per cent was obtained with Difolitan 80W.
+ Botran, 1.5 lb. + 1.2 lb/100; Captan 2 lb/100, 98.33 per cent; and Sulphur
6 lb/100 98.34 per cent. The least effective fungicides after 4 days storage
were: Daconil (2787) + Botran, 2 lbs + 1.2 lbs/100; 11.67 per cent and Kolo
100 + Botran, 6 lbs. + 1.2 lbs/100; 15.47 per cent diseased fruit. The
disease on the unsprayed peaches was very light as only 7.58 per cent
brown rot infection developed during these 4 days in storage. The best dis-
ease control after 7 days storage at 70 to 80 degrees F., was obtained with
Captan 50W + Botran, 2 lbs. + 1.2 lbs/100, 85 per cent followed by Difloitan
80W + Botran, 1 lb. + 1.2 lb/100, 84.5 per cent

The addition of Botran in the last three spray applications improved
the effectiveness of Difoliation 80W, Captan and Sulphur in controlling
Rhizopus rot, but did not reduce the brown rot infection. In these tests
Botran reduced the fungicidal effectiveness of Cyprex + Captan. After
7 days in storage Kolofog and Kblo 101 were not as effective as Sulphur
in controlling Brown rot and Rhizopus rot.
















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PAGE 1

~' -~BIG BEND HORTICULTURAL LABORATORY MONTI CELLO, Florida Big Bend Hart. Lab. Miimeo Report BBL 67-9 April 20,1967 EVALUATION OF DIFFERENT FUNGICIDES FOR THE CONTROL oF PEACH SCAB (CLADOSPORIUM CARPOPHILTJM), BROWN ROT (IIONILINIA FRUCTICOLA), ANDRHIZOPUS ROT (RHIZOPUS SP.), ON MAYGOLD PEACHES AT -.0ffJ8A IN 1966. by J. L. Large.1. INTRODUCTION The production of peaches is a new but rapidly groyib X 4 3 Q a The 1964 Dare report states that there are at least 4,000 acres now Mn yawig and non-bearing trees. In 1966 Sharpe (Florida Grower and Rancher, August, 1966) estimated that around 3,500 acres have been planted in Central Florida, North of the line extending from Brooksville to Sanford; and Young, 1966 (Mimeo Report BBL 66-4) estimated there were 3,953 acres in North Florida, principally in Madison, Jefferson, Holmes, and Leon counties. With this rapid growth in commercial production there is a need for research on timing of applications and testing of fungicides for the control of the following leaf and post harvest diseases; 1. Brown rot and blossom blight Monilinia fructicola (Wint.) Honey. 2. Bacterial leaf spot Xanthomonas pruni (E.F.Sm) Dows. 3. Scab Cladosporiur carpophilum ('Lev.Aderh. 4. Rust Tranzschelia discolor (Fckl) Tranz & Litv. 5. Peach leaf curl Taphrinia deformans (Berk.) Tul. 6. Brown rot of fruit Monilinia fructicola (Wint.) Honey. 7. Grey Mold of fruit Rhizopus Ms. METHOD OF PROCEDURE Maygold peach trees, planted in February 1964, were sprayed with eight applications with a hand gun using dilute sprays applied at 450 P.S.I. The first was a dormant spray of liquid lime sulphur, 5 gal/lOO gallons of water applied just before bud break (March 1). This spray was used in all treatments except the unsprayed check. The dormant spray was followed by fungicide and insecticide spray applications on March 22 (shuck split), April 5, April 28, May"6, May 12, May 19, and May 24. Malathion 25WP, 3 lbs/lOO was used in dormant and first 3 cover sprays. Guthion 75W,.4 ozs/lOO was used in I. the four May applications to control insects. Ten fungicides with three one-tree replications of each treatment were used. Botran 75W., 1.2 lb/l0O was included in the last three sprays on half of the trees. Leaf disease counts were made April 4, 19, and May 3rd. The monthly rainfall was as follows; (1) M'arch 2.72 inc1 ~ ;-ir-n o.~ V _qS June 1 to 15, 5.72. H M IR R 1Associate Plant Pathologist 200 cc

PAGE 2

-2FUNGICIDES TESTED The fungicides tested were; Daconil: (2787) 2 lbs/100; Difolitan SOW, 1 lb, and 1 1/2 ibs/iQO; Captan 50W, 2 lb/lOO; Cyprex + Captan SOW, 1/2 lb +1 1/2 lbs/lO0; Kolofog, 6 lbs/lO0; 1olo-lOO, 6 lb/lO0; Sulphur, 6 lbs/100; Polyram 8OW, 2 ibs/iQO; Kocide, 6 lbs/lO0 (2 applications) then sulphur, 6 lbs/100; Dormant Lime-Sulphur 6 lb/l0O; and unsprayed trees. Botran 1.2 lbs/ 100 was used on half the trees (3) of each treatment in the last 3 applicat. i, ions and for one treatment it was used in 7 applications with Difolitan BOW. DISCUSSION OF LEAF DISEASES Blossom blight, Peach leaf curl, bacterial spot, and rust were of minor importance on sprayed foliage this season. Scab was serious (39% infection) on unsprayed trees. No scab was found on trees sprayed with Captan SOW, 2 lbs/l0O, Captan + Botran, 2 lbs + 1.2 lbs/l0O, Polyram, 2 lbs/100, or Daconil (2787) + Botran, 2 lbs + 1.2 lbs/lOO. Leaf counts made May 28 to May 30, indicated that peach leaf curl, bacterial spot, and rust were of minor importance on sprayed trees this season. (Table I). Bacterial spot was most severe on leaves sprayed with Kocide 2 lb/lOO. Two applications of this fungicide, which contains copper hydroxide, caused yellowing and marginal necrosis of the foliage, with :30 to 50% defoliation. These trees were sprayed with Sulphur 6 lb/lO0 in the last 6 applications. CONTROL OF STORAGE DISEASES Peaches, 30 per tree, (90 per spray treatment) were stored at room temperature, 70 to 80 degrees F., for 4 and 7 days. The percentage disease infection after 4 and 7 days are recorded in Table II. The disease infection on the fruit was very light and generally less than 5 per cent, after 4 days storage at room temperature. The best disease control after 4 days storage, 100 per cent was obtained with Difolitan 80W. +]otran, 1.5 lb. + 1.2 lb/lO0; Captan 2 lb/l00, 98.33 per cent; and Sulphur 6 lb/l00 98. 34 per cent. The least effective fungicides after 4 days storage were: Daconil (2787) + Botran, 2 lbs + 1.2 lbs/l00; 11.67 per cent and Kolo, 100 + Botran, 6 lbs. + 1.2 lbs/100; 15.47 per cent diseased fruit. The disease on the unsprayed peaches was very light as only 7.58 per cent brown rot infection developed during these 4 days in storage. The best disease control after 7 days storage at 70 to 80 degrees F., was obtained with Captan S0W + Botran, 2 lbs. + 1.2 lbs/lO0, 85 per cent followed by Difloitan 80W + Botran, 1 lb. + 1.2 lb/100, 84.5 per cent The addition of Botran in the last three spray applications improved the effectiveness of Difoliation SOW, Captan and Sulphur in controlling Rhizopus rot, but did not reduce the brown rot infection. In these tests Botran reduced the fungicidal effectiveness of Cyprex +Captan. After 7 days in storage Kolofog and Kblo 101 were not as effective as Sulphur in controlling Brown rot and Rhizopus rot.

PAGE 3

TABLE 1. Leaf Disease Infection of Peach Foliage, Data Taken April 4, 19, And May 3, 1966. Scale of Infection 0, Trace to 5. TREATMENT Pounds/100 Leaf Bact. Leaf Bact. Scab Leaf Bact. Scab Rust Curl Spot Curl Spot Curl Spot Daconil(2787 ) 2/100 0 T T 2 0 0 T T 0 Pifolitan 80 W 1/100 0 T T T 0 0 0.5 T 0 Captan 50 W 2/100 0 T 0 T 0 0 0.5 T 0.5 Cyprex Captan 1/2-100 0 T T 10 0 1+ 1T 1Kolofog 6/100 0 T 0 0 0 0 0 T 0 Kolo 100 3.6/100 0 T 0 T 0 0 T 0 0.3 Sulphur 6/100 0 1+ 0 10 0 T T T Polyram 2/-100 0 T T T 0 0 0.5 T T Kocide 2/100 0 1+ 0 4 0 0 3 T 0 (2) S-61b./100 Botram 4/100 0 T T 1 0 T 1 0.3 T Dorm Lime-S 6/100 1+ 0 T T 0 0 T 0.25 0 Not Sprayed 0 0 0 0 0 0 0 T T 0 T-TRACE

PAGE 4

TABLE11. Fercentage of Diseased Peaches After S',,,rage at 70 Degrees to 80 Degrees F. [uring A 4 and 7 Day Post Harvest Ripening Period. Fungicide,rate pe-r 100 gal. Peaches After 4 days Fruit affected After 7 days of water & no. of sprays harvested Scab Healthy Brown Rhizopus HealthyBrown Rhizopus (7) or (3). Number %% Rot% Rot% % Rot% Rot% Difolitan 801,(7)Botran 75W(7) 1.5 +1 lb./100 1042 0.0 100 0.4~ 0.0a 76.5 16.8 5.0a Llfolitan(7)+Botra-n (3) 1 lb + 1.2 lh./100 627 7.8 100 0.Oa 0.Oa 84.5 15.5a 2.2a Difolitan (7).1'lb.,'100 757 5.0 95.6 0.9a 3.5a 75.9 12.9a 11.2b Captan 50W(7)*B04ti"a'i(3) 2.0 lb. + 1.21b./100 457 0.0 96.7 3.3a 0.Oa 85.0 12.5a 2.5a Captan (7) 2 lb./100 651 4.2 98.4 0.8a 0.8a 80.0 10.9a 6.6a Cyprex 65W+Captan(7)+Botran(3) 0.5 lb.+1.5 lb.+1.2 lb;/100 495 3.6 92.5 0.Oa 7.5b 63.3 10.Oa 25.6b Cyprex + Captan (7) 0.5 lb. + 1.5 lb./100 757 1.1 97.7 2.3a 0.Oa 72.0 21.9a 5.Oa Sulphur(7)+Botran(3)6#+1.2/100 531 3.3 96.5 3.5a 0.Oa 63.0 26.1b 10.9b Sulphur(7) 6 lb./100 1229 1.7 98.3 1.7a 0.Oa 63.3 11.7a 24.2b Liquid Lime-Sulphur(Ihe 71 5. 3. .6 .a 39 95b 66 (3) 6 lb. then 1.2 lb/10t171.6 934n.b otr7.a1.5n66 Liquid Lime Sulphur(1) 6 lb./100 679 23.3 97.6 1.6a 0.8a 43.1 44.7c 9.8b Not sprayed 1873 39.3 92.4 7.6b 0.Ob 40.3 33.1c 25.4b *All scab data was taken at harvest. "*Thirty rot-free peaches were selected from each tree per treatment. These peaches were stored at 70-80 degrees F. for 4 and 7 days to determine the residual effectiveness of the pesticides. In some cases blue mold on fruit or brown rot and rhizopus rot on one fruit caused the total percentage to be more or less than 100 percent. Values followed by the same letter do not differ significantly at the .05 level.