


Fate Glad Chee 
It surely seems as if we glad growers have more than our fair share of trouble. As if thrips 
and the various fungus and bacterial diseases we:c not enough, new pests bob up before we have 
had a chance to draw a deep breath after fighting the old ones. Among the new enemies of glads 
are the various virus diseases - some of these are not entirely new, but others are. 
In the broad sence of the term, the name virus is applied to the poison produced by the 
specific germs or bacteria that cause the various contagious diseases. In the great majority of 
contagious diseases science has been able to isolate the germ that causes the disease, but there 
are some diseases for which no specific germ has ever been found, but which are, without question, 
due to a virus. Such diseases as small-pox, chicken-pox, and probably mumps, measles, and infan- 
tile paralysis, are in this class. It is to these that the term virus disease in its more limited sense 
is applied. 
Virus is invisible: neither the most powerful microscopes nor the latest electronic devices have 
demonstrated any visible form - it is apparently not corporal. But, whatever form it is in, it very 
definitely is able to reproduce and perpetuate itself - as we know only too well. 
Virus attacks plants as well as man and animals and, unfortunately, gladiolus are among the 
plants susceptible to virus infection. Plant pathologists of the U. 8. Dept. of Agriculture have lately 
devoted a great deal of time to the study of virus disease in glads and they have been able to 
determine certain facts that will materially benefit growers. One of these is that, contrary to the 
belief held for some time, virus is not a soil borne disease: all the data seem to prove very de- 
finitely that virus cannot survive in the soil. This is very important. 
If virus is not a soil borne disease, how then is it transmitted to gladiolus? Experiments were 
made to determine whether virus could be transmitted to healthy plants through contact with virus 
infected plants and the results were negative. Next, the juice from infected plants was rubbed into 
the rasped surfaces of healthy plants, and, while some viruses occasionally were transmitted by 
this method, others were not. Obviously, the virus could not infect healthy plants through trans- 
mission by air currents. There remained one other plausible method of infection, transmission of 
the virus by insect carriers - and the scientists turned their attention to insects. This line of investi- 
gation brought results. It was found that legumes were the source of the virus, and that aphids, or 
plants lice, that ordinarily live on peas, beans, sweet clovers, alfalfa, and other legumes were the 
vectors, or carriers, that conveyed the virus to gladiolus. 
The nature of viruses makes it seem extremely improbable that any antidote for virus infection 
will ever be found, but we do have an effective means of fighting virus disease at our disposal - 
that is to destroy each infected plant just as soon as the disease can be detected. In some types 
of virus signs of the disease appear early, such as mottling of the foliage, or stunted growth, or 
deformed foliage, but in others, notably the type called ‘white break’’, no signs usually appear 
until the florets open - when they become all too obvious. The thing that makes early detection 
of white break impossible is the fact that the infected plants usually appear especially healthy and 
robust. 
In dealing with any virus it is important to remember that the bulblets from a diseased bulb 
carry the virus and that therefore all bulblets must be destroyed, as well as the bulb. If all diseased 
piants, together with all of their bulblets, are promptly removed and destroyed, preferably by burn- 
ing them, any planting can be quickly rogued of virus infected stock. 
If virus turns up in larger plantings it will be necessary to carefully scan the rows at least 
every few days in order to make sure that no diseased plants are overlooked. 
As to preventive measures: avoid planting gladiolus in close proximity to fields of legumes, 
since it is known that such plantings are the regular natural source of such viruses. It need hardly 
be stated that the grower of glads had better not plant any peas or beans if his vegetable garden 
is anywhere near his gladiolus patch. 
This is a good time to state that, apparently, no variety of gladiolus is immune to virus in- 
fection. 
