Title: Recommendations for control of late blight of potatoes
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00076281/00001
 Material Information
Title: Recommendations for control of late blight of potatoes
Physical Description: Book
Creator: Eddins A. H.
Publisher: Potato Investigations Laboratory,
Copyright Date: 1956
 Record Information
Bibliographic ID: UF00076281
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: 133562681 - OCLC

Full Text

Hastings, Florida',

Mimeo Report 57-1 October 1, 1956

A. H. Eddins

A spray containing 2 quarts nabam (Dithane D14 or Parzate Liquid) and 3/4 to

1 pound spray grade zinc sulfate in 100 gallons of water is recommended for con-

trolling late blight. Zineb 65% (2 lbs./lO0 gals.) and Manzate 75% (1) lbs./100

gals.) also are recommended.

The number and frequency of applications of spray required to control late

blight in the Hastings area vary according to the severity of the disease, which is

more prevalent and destructive in a wet growing season than in a dry one. Make the

first application of spray when the plants are six to eight inches tall or before

then if the disease appears earlier. During dry seasons spray the plants at least

five times at five to 10-day intervals to prevent damage from late blight and to

combat early blight. During wet seasons when plants are attacked by late blight

soon after they emerge from the soil and weather conditions favor its development

until harvest, it may be necessary to spray the plants ten times or more at four-

to seven-day intervals to obtain satisfactory control.

Apply the spray as uniformly as possible with a tractor-operated sprayer

equipped with a six- to twelve-row boom and enough nozzles per row to cover the

plants with the spray. Good control can be obtained by using 100 to 125 gallons

spray per acre on small plants at the first application. Increase this quantity as

the plants grow larger and apply 165 to 175 gallons per acre to cover full-grown


Nabam-zinc sulfate, zineb and maneb are compatible with the insecticides, DDT,

parathion, toxaphene and chlordane which may be used for control of insect pests of


Directions for Making Nabam-4inc sulfate Spray

1. Start running water in tank with agitator going.

2. Keep agitator going while spray is being mixed.

3. Pour in 2 quarts nabam (Dithane Blkor Parzate Liquid) for each 100 gallons

water after agitator is covered with water. Allow at least one minute for the

nabam to mix with the water&

4. Slowly pour in 3/4 to one pound of finely granulated or completely dissolved

zinc sulfate (36 percent metallic zinc equivalent) for each 100 gallons. Allow

at least two minutes for the zinc sulfate to react with the nabam.

5. Add 1 quart 25% DDT emulsion for each 100 gallons of spray for aphid control on

potatoes. If DDT emulsion is not giving satisfactory control of aphids, use

parathion, 1 pint 25 percent emulsion or equivalent per 100 gallons spray. No

spreader-sticker is needed when the spray is used on potatoes.

6. Keep agitator going in sprayer and auxiliary tanks until the spray is applied.

Materials Required to Make Different Quantities of Spray

For Late Blight Control For Aphid Control

Water Nabam Zinc Sulfate 25% DDT Emulsion OR 25% Parathion
Gallons Quarts Pounds Quarts Emulsion, Pints*

100 2 3/4 to 1 1 1

200 4 1 to 2 2 2

300 6 2 to 3 3 3

4oo 8 3 to 4 4 4

500 10 3 3/4 to $ 5 5

*Note that quantities of parathion required are measured in pints not quarts.

300 copies

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