RIVERVIEW GARDENS, ST. PAUL, MINN. 
7 
Gladiolus Thrips 
Fortunately we are not troubled with Gladiolus thrips in our plantings. Our 
fields and bulbs in storage have been passed one hundred per cent free from thrips. 
These thrips are about 1/T6th of an inch long and have a cream band across 
the back or dark brown body. Orange colored larvae may also be present in the 
leaf sheaths and in the flower buds. They attack the growing plant, the flower 
and the bulbs in storage, whitening the leaves and flowers and leaving a sticky 
brown stain on the bulbs, and, if present in sufficient numbers, may cause a great 
amount of damage. 
The first thing to do is to see that the bulhs planted are not infested, as the 
thrips will travel up the growing stem, attacking the leaves and later the flowers. 
If you have never had trouble with thrips the best way to keep your Glads free 
from their attacks is to be exceedingly careful not to buy them on the bulbs. 
If you have had trouble with thrips or diseases previously it is advisable to 
dip the bulbs in a solution of corrosive sublimate (1 ounce to 7 gallons of water) 
for about 7 to 12 hours. This treatment thoroughly disinfects the bulbs, killing 
all possible thrips and their eggs, and is also a protection against disease. 
When plants are about four inches tall and thrips are found, it is best to use 
a solution of the following as a weekly spray. One rounded tablespoonful of Paris 
green, two pounds of brown sugar and three gallons of water. Always endeavor to 
have the thrips under control before the buds appear. 
When digging, cut off the tops close to the bulbs and burn immediately, as the 
thrips will quickly migrate from the dying leaves to the bulbs and live on them 
until next planting season if unchecked. During storage napthalene flakes may be 
used at the rate of I ounce (4 tablespoonfuls) to every 100 bulbs. The correct 
amount of this material is sprinkled over the bulbs in paper bags, trays, or boxes 
and the fumes confined by folding over the top of the bags or by covering the 
trays with wrapping paper or light canvas. The flakes should remain with the 
corms for a period of at least one week at 60 to 70 degrees F., but three to four 
weeks are preferable at lower temperatures. When the fumigation is complete 
the excess flakes should be shaken out. 
We will be pleased to supply additional information on any subject pertaining 
to the Gladiolus. 
We have removed thousands of names from our mailing list. If you do 
not order and have not ordered for the past two years, and still wish to 
remain on our mailing list, please drop us a post card. We will be only too 
glad to send you a copy of our next year’s catalog. 
