SCHENCK AND ADLERZ: WATERMELON FERTILIZERS 209

COMPATIBILITY OF INSECTICIDES, FUNGICIDES, AND

FOLIAR FERTILIZERS ON WATERMELON

N. C. SCHENCK AND W. C. ADLERZ1

Florida Agricultural Experiment Station

Leesburg

Insecticides, fungicides, and foliar fertilizers

are all used in the production of watermelon

(Citrullus vulgaris L.) in Florida. In certain

areas of the state, particularly in south Florida,

pesticides are commonly applied at 5-7 day in

tervals to maintain disease and insect control.

Growers with large acreages combine insecticides

and fungicides so that both can be applied at the

required short interval. In addition, materials

are combined simply to save the time and labor

required to make separate applications.

Several pesticide-nutritional spray mixtures

have been suspected of causing physical damage

to watermelon plants, but no recommendations

have been made regarding the phytotoxicity of

these spray mixtures because of the lack of ex

perimental evidence. In addition, little was known

about the pesticidal effectiveness of these mix

tures.

In 1952, Kelsheimer et al. (3) compared 20

different pesticide-nutrient mixtures for their

compatibility on several vegetable crops. Al

though many of the materials tested in that study

are still in use, several new pesticides and nu

trients have since become available.

Several references report fungicide-insecticide

compatibilities on crops other than vegetables (4)

(5) (6), but no nutrients were included in these

tests, and results are not entirely applicable to

vegetable crops. In addition, pesticide mixtures

have been compared for compatibility in seed

treatment of cucurbits (7), peas (8), and corn

(1), but these results have little application to

the compatibility of pesticide mixtures as foliar

sprays.

The purpose of this paper is to preliminarily

report the progress of an evaluation of several

pesticide-nutrient combinations for their effect

on watermelons. Perhaps this report will stimu

late the interest of other researchers to perform

similar experiments on other crops and also act

as a deterrent to indiscriminate mixing of ma

terials in the spray tank.

lAssistant Plant Pathologist and Assistant Entomologist, respectively, Watermelon and Grape Investigations Labora

tory, Leesburg, Florida. T Florida Agricultural Experiment Stations Journal Series,

No. 1579.

Materials and Methods

Pesticide and pesticide-nutrient mixtures were

evaluated in the field on variety Charleston Gray

watermelon arranged in plots of 10 hills in 2

paired rows. The experimental design was a ran

domized block of 3 replicates, and the entire ex

periment was bordered with a row of Fairfax

watermelons. In addition, in 1962, separator rows

of variety Summit were planted between plots.

In 1961 there were 24 treatments consisting

of all possible combinations using 1 each of 4

insecticides, 3 fungicides, and 2 foliar fertilizers.

Materials and rates (for 100 gallons of water)

were as follows: fungicidesDithane Z-78 (75%

zineb w.p., Rohm and Haas Co.) at 1 lb. plus

Manzate (80% maneb w.p., E. I. duPont de Ne-

mours and Co.) at 0.75 lb.; Captan 50 (50%

captan w.p., California Chemical Co.) at 2 lb.;

Tribasic Copper Sulfate (53% metallic copper

as basic copper sulfate) at 3 lb.; insecticides

Dibrom 8E (100% naled emulsifiable liquid, Cali

fornia Chemical Co.) at 1 lb.; Diazinon 25W

(25% diazinon w.p., Geigy Chemical Co.) at 2

lb.; Phosdrin 25W (25% phosdrin w.p., Shell

Chemical Co.) at 1 lb.; Thiodan 50W (50% en-

dosulfan w.p., Niagara Chemical Division) at 1

lb.; fertilizersNugreen (45% urea jntrogen,

E. I. duPont de Nemours and Co.) at 4 lb.; ni

trate of soda-potash (15-0-14, Chilean Nitrate

Sales) at 5 lb.

In 1962 there were 48 treatments consisting

of all possible combinations using 1 each of 4

insecticides, 4 fungicides, and 3 foliar fertilizer

treatments. Materials and rates were as follows:

fungicidesDithane Z-78 at 2 lb.; Manzate at

1.5 lb.; Phaltan (50% folpet w.p., California

Chemical Co.) at 2 lb.; Dithane M-45 (16%

manganese, 2% zinc, 62% ethylenebisdithiocar-

bamate, Rohm and Haas Co.) at 2 lb.; insecti

cidesDibrom 8E at 1 lb.; Diazinon 25W, at 2

lb.; Thiodan 50W at 1 lb.; Guthion 25W (25%

guthion w.p., Chemagro Corp.) at 2 lb.; ferti

lizersNugreen at 4 lb.; nitrate of soda-potash

at 5 lb.; none.

Treatments were applied at approximately

125 psi from a Meyers 25-gallon Research Sprayer

with a 12-foot boom bearing 11 nozzles. Treat

ments were applied at 10-14 day intervals 4 times

in 1961 and 6 times in 1962. In both years disease

ratings were made at weekly intervals, using a

210 FLORIDA STATE HORTICULTURAL SOCIETY, 1962

Table 1. Effectiveness of various fungicides in the control of watermelon diseases^ 1961 and 1962,

Mean disease ratings^ 190I 19o2

Zineb-maneb

Copper

Captan

3.7 a<

4.5 b

5.1 c

Maneb

M-45

Folpet

Zineb

3.9 a2

5.2 b

6.0 c

6.4 c

1 Rating system scale 0-11.0; 1.0 = trace of disease, 11.0 = 100$ infection.

2 Values followed by the same letter nonsignificantly different according to analysis of variance.

Table 2. Effect of insecticides on the fungicidal

control of watermelon diseases, 1961.

Insecticide Mean

Phosdrin

Dibrom

Diazinon

Thiodan

disease rating

4.1 a

4.3 a

4.3 a

4.8 b

Table 3. Effect of fertilizers on disease and

insect control.

1961

Disease rating

15-0-14 4.2 a

Nugreen 4.6 b

None

1962 Percent rindworm

damaged melons

53.4 a

52.9 a

60.6 b

Table 4. Control of rindworm of watermelon by

insecticides, 1962

Insecticide

Guthion

Thiodan

Diazinon

Dibrom

Mean percent

damaged melons

41.4 a

57.2 b"

59.7 b

62.9 b

modification of HorsfalFs method (2). Melon

numbers and weights were recorded twice in

1961 and 3 times in 1962. Melons damaged by

rindworm were counted at the time of picking

in 1962. Other insect infestations did not develop

during either test.

Results and Discussion

Differences in disease control in 1961 resulted

principally from the major effects of fungicides,

insecticides, and foliar fertilizers rather than

from their interactions. In 1961 zineb-maneb

was significantly better than copper, which was

significantly better than captan. In 1962 maneb

and Dithane M-45 were significantly better than

folpet and zineb; maneb was also significantly

better than M-45 (Table 1). Disease control with

mixtures containing thiodan was significantly

less than control with those containing other

insecticides (Table 2). Combinations with Nu

green were significantly poorer in disease control

than those with 15-0-14 (Table 3).

A rindworm infestation in 1962 was the only

insect problem encountered during these tests.

Rindworm damage was significantly less in plots

sprayed with guthion than in those sprayed

with other insecticides (Table 4). Rindworm

damage also was significantly less in plots

sprayed with mixtures containing fertilizers than

in those sprayed with mixtures not containing

fertilizers (Table 3). Rindworm control was re

duced when insecticides were combined with di-

thiocarbamate fungicides in the absence of fer

tilizers (Fig. 1). However, control was not re-

SCHENCK AND ADLERZ: WATERMELON FERTILIZERS 211

5

o

i o

|

66 r

62

56

54

o: 50

46 FOLPET ZINEB

MANEB

FERTILIZER

FOLPET ZINEB

MANEB

NO FERTIUZER

Figure 1.Effect of fungicides and fertilizer combinations on insecticide control of rindworm of watermelons, 1962.

duced in similar combinations with folpet.

There were no significant differences in yield

due to the major effects of fungicides, insecti

cides, or foliar fertilizers.

Certain combinations were involved in sig

nificant interactions indicating apparent incom

patibility (Table 5). These interactions were not

supported statistically by significant major effects

or lower order interactions or both, which con

siderably lessens their importance. However,

these combinations are worthy of note and fur

ther evaluation.

Summary

In a 2-year study (1961-1962) 72 combina

tions of insecticides, fungicides, and foliar fer

tilizers were compared for their compatibility

on watermelon. In these tests disease control

was best with zineb-maneb and maneb alone.

Disease control with mixtures containing Thiodan

or Nugreen was significantly less than with mix

tures not containing them. Rindworm control

was best with guthion and mixtures containing

foliar fertilizers. Insecticidal control was re

duced by mixtures containing dithiocarbamate

fungicides without fertilizers. Other combina

tions showing apparent incompatibility will be

tested further.

LITERATURE CITED

1. Arnold, E. W. and J. W. Apple. 1957. Compatibility of insecticides and fungicides used for the treatment of corn seed. J. Econ. Entomol. 50:43-45.

2. Horsfall, James G. 1945. Fungicides and their action. Chronica Botanica Co. Waltham, Mass. p. 38-41.

3. Kelsheimer, E. G., James M. Walter, J. R. Becken-bach. 1952. Compatibility of insecticides, fungicides and nutrients for vegetable crops. Florida Agr. Expt. Sta. Circ.

S-47. 6p. 4. Kelsheimer, E. G. 1958. Compatibility of insecticides

Table 5. Pesticide-fertilizer combinations involved in interactions

indicating apparent incompatibility in 196l or 1962,

Combinations

Disease Percent rindworm Yield

ratings damaged melons (pounds per acre)

Thiodan/zineb-maneb/Nugreen 7.0

Thiodan/15-0-14

Diazinon/zineb-maneb/Nugreen

Phosdrin/captan/Nugreen

Dibrom/zineb-maneb/Nugreen

Diazinon/M-45/15-0-l4

Diazinon/zineb

Experiment mean 3.5

-

-

-

-

83^7

86.7

55.3

17,932

9,655

15,100

15,560

-

0

20,839

.2

.8

.8

.6

.2

212 FLORIDA STATE HORTICULTURAL SOCIETY, 1962

and fungicides for chrysanthemums. Proc. Florida State

Hort. Soc. 71:392-394. 5. Madsen, H. F. and Stanley C. Hoyt. 1962. Compati

bility chart of spray chemicals. Western Fruit Grower

16(2):26-29. 6. McBride, J. J., Jr. 1958. Reaction of zineb with

copper compounds, oil deposits when applied with zineb and deposits of zineb when applied with a variety of ma

terials. Proc. Florida State Hort. Soc. 71: 118-122. 7. Natti, J. J., W. T. Schroeder, G. E. R. Hervey, and

F. L. McEwen. 1958. Value of insecticide-fungicide combi nation treatments as protectants for seed of cucumber and winter squash. Plant Disease Reptr. 42:127-133.

8. Richardson, Lloyd T. 1960. Effect of insecticide-fungicide combinations on emergence of peas and growth of damping-off fungi. Plant Disease Reptr. 44:104-108.

PROGRESS REPORT ON POLE BEAN BREEDING AT THE

SUB-TROPICAL EXPERIMENT STATION

Robert A. Conover

Sub-Tropical Experiment Station

Homestead

Pole bean acreage in Dade County has in

creased steadily during the past decade so that

pole beans are now the second most important

vegetable crop grown in the county. About

7,000 acres were planted during the 1960-61 sea

son with production valued at $4,000,000. Dade's

crop accounts for about 85% of Florida's pole

bean acreage and 20% of the value of all green

beans produced in Florida.

The principal hazard to successful pole bean

production is bean rust caused by the fungu-3

Uromyces phaseoli typica Arth. Rust makes its

appearance in the fall, gradually builds up dur

ing the winter, and reaches a peak of destruc-

tiveness during the spring. Sulfur dust provides

adequate control during the fall and early winter,

but is inadequate when rust is severe. Dusts con

taining sulfur plus 3.5% maneb will control rust

under severe conditions but twice weekly appli

cations may be required. These dusts are expen

sive and close attention must be paid to details,

especially timing of applications, if satisfactory

control is to be obtained.

There are several other diseases and disorders

which may affect certain pole bf^an varieties.

The common bean mosaic and the Southern bean

mosaic viruses are sometimes devastating in sus

ceptible varieties. Resistances to both viruses are

available in present day varieties. Yellow bean

mosaic is sometimes a problem in Dade County,

particularly in small plantings near groves and

residences. Resistance to this virus is not known

in beans. Intumescence and black suture, two

physiological disorders thought to be induced by

environmental factors, are occasionally severe

in pole beans.

McCaslan is the only pole bean variety grown

to any extent in Dade County. It is well adapted

to the winter-growing conditions and to the cal

careous soils of Dade County, is resistant to the

common bean mosaic virus, black suture and in

tumescence, but it is very susceptible to rust.

The pods of McCaslan are too light in color,

and are also criticized for being flat and rough.

Other varieties, such as U.S. No. 4 (No. 191)

and Florigreen, have not found favor with

Dade County growers, although the latter is

rust resistant, and both have features which are

desirable in pole beans. Both Florigreen and

U.S. No. 4 are susceptible to black suture and

intumescence. Florigreen is resistant to the com

mon and Southern bean mosaic viruses.

The Florida Agricultural Experiment Sta

tions initiated a state-wide pole bean breeding

project* in 1957 to coordinate work being done

at several locations in the state. The main ob

jective of this project, as it applies to the Sub-

Tropical Experiment Station, has been to de

velop a high yielding, rust resistant pole bean

adapted to Dade County conditions, and produc

ing good quality pods able to withstand the rigors

of marketing. The immediate and primary aim

has been to develop a high yielding pole bean

combining the vigor and adaptability of McCaslan

with the rust resistance and pod color of Flori

green. Uniformity in length, straightness, and

smoothness of pod was sought in every selection.

This paper is a report of the progress made

toward developing a pole bean variety with these

features.

Most of the work at the SES has been pri

marily concerned with selections from a cross

of McCaslan and Florigreen made by Dr. A. P.

Lorz of the Main Station, Gainesville. Selec

tions from this cross have proved to be highly

resistant to rust, and to produce yields that

equal or exceed the yields of either parent. In

addition these stocks possess, in varying degree,

most of the features considered desirable in a

^Project 887: Breeding of Improved Pole Bean Varieties

for Commercial Production in Florida.