Group II 
The second group, at the other extreme as to susceptibility, 
consists of those lilies that resist infection to the point where they 
can be safely considered immune. 
L. Brownii (type) L. Martagon (all forms) 
L. giganteum himaliacum L. pardalinum (all forms) : 
L. Hansonii The Martagon-Hansonii hybrids 
Group III 
The third group is liable to infection but does not acquire it 
readily and tends to survive for a number of years in the garden, 
though the plants will gradually deteriorate somewhat and may finally 
die out.1 
L. regale L. Maxwill1 
L. tenuifolium L. sulphureum! 
L. Willmottiae1 L. monadelphum Szovitzianum! 
L. Henryit All of the Preston, Stooke’s and 
L. cernuum Bellingham hybrids! 
Group IV 
The fourth group consists of those lilies that are most highly 
susceptible to infection and rarely survive more than a single season 
when infected.1 
L. auratum L. japonicum 
L. canadensel L. superbum! 
; L. formosanum 
These classifications while an invaluable guide to the gardener 
are somewhat artificial. Actually the two hundred odd varieties and 
species of lilies run the whole gamut from susceptibility to immunity 
and within each classification there is considerable range in regard to 
immunity. This is particularly true of Group IV in which L. auratum, 
L. formosanum, and L. japonicum are the most highly susceptible that 
we know, while L. canadense and L. superbum can stand a fairish 
amount of exposure. Now and then we find individual clones that 
show a real degree of resistance. 
Mosaic is spread from one plant to another ONLY by means of a 
small group of sucking and chewing insects. It does not travel through 
the air or soil. Aphis are the principal culprits. The farther north one 
goes the fewer aphis one finds. At Sandyloam we have none. We be- 
lieve that our only mosaic carrier is the potato leaf hopper. The insect 
carriers are almost invariably wind blown or crawling and conse- 
quently do not tend to travel very far, not more than 30 to 50 feet in 
the garden. 
With this knowledge as a basis the gardener can order and plant 
his lilies with more understanding and with relative safety and con- 
fidence. Lilies from Groups I and II are completely reliable. They will 
never perish from mosaic, and they can be planted any place without 
fear as to their susceptibility. 
The lilies in Group III can be ordered with a good deal of con- 
fidence. They are all of them first rate garden lilies and even if infect- 
ed with mosaic will be excellent garden plants for many, many years. 
1 Those designated are less susceptible than the others within the 
given group. Also, individual plants within Groups III and IV may 
prove relatively resistant. 
=| E80mls 
