Pesticide User's Guide

Bulletin 745

Storing Pesticides for Next Season

Growers storing pesticides should always consider safety and product quality, whether storage is for a few weeks or a year or more. It is best not to have leftover pesticides. However, there are usually surplus pesticides left over at the end of the season and preseason purchases often are very economical.

The following points should be followed:

1. Read the label. Certain formulations or products have special storage requirements. Those restrictions or directions will be printed on the label.

2. Make certain that the label is in good condition (readable) in order to know what is in the container and have directions for safe, effective and legal use.

3. Write down the purchase or delivery date on the label. Use older or opened products first. Products several years old may not be effective.

4. Keep an up-to-date inventory of pesticides to assist in purchase decisions and in case of emergency.

5. Usually storage temperatures should not go below freezing nor above 100 degrees F. Ventilation is important for storage of most pesticides. Keep pesticides dry and out of direct sunlight.

6. Store insecticides away from herbicides to prevent use mixup, contamination and possible plant damage. Never store pesticides with feed and seed.

7. Pesticide storage areas should be placarded and locked away from children, irresponsible adults and animals.

Certain pesticides are listed below with statements on their self life under normal conditions:

Insecticides

carbaryl (Sevin) WP - several years
carbaryl (Sevin) F-watch for settling
diazinon EC - 5 to 7 years if tightly sealed
disulfoton (Di-Syston) - 2 years
malathion WP - many years, but decomposes under high temperatures
Metasystox-R - 2 years
methoxychlor many years
phosmet (Imidan) WP - 2 to 3 years

Fungicides

benomyl (Benlate) WP - 2 years, but decomposes in moisture conditions
Captan WP - 3 years

Herbicides

glyphosate (Roundup) - 2 years, don't allow to freeze
casoron (G) - 2 years, if cool and dry
Dacthal (WP) - 2 years
Kerb (WP) - 2 years
simazine (Princep) (G, WP) - many years
Surflan (G) - 3 years, mix well
Treflan (G) - 3 years, if dry and under 80 degrees F