RUBBER (HEVEAj DISEASES 53 
INJURIES CAUSED BY PHANEROGAMIC PLANTS 
MISTLETOES 
The mistletoes (Loranthaceae) are very common throughout the 
Amazon Valley, attacking a great variety of trees and shrubs. 
Young mistletoe plants in the first cotyledon stage have even been 
found on such temporary substrata as the fruits of the banana, 
pai-aya. breadfruit, avocado, and soursop. Aside from the numer- 
ous specie- which are usually found on trees, vines, and shrubs in 
the forest, some of which are occasionally transferred to PL 
certain other species show an affinity for some of the horticultural 
plants. 
Cacao is attacked by Phthirusa pyrifolia and 0\ 
Oranges and limes are attacked by both the above-nai 
ies and by Phthirusa brasUiensis. The mango is frequently 
attacked by Phthirusa pyrifolia* 
Struthantl 'eaulis^ a vining species, is of common occur- 
rence on both the wild and planted cashew. It was found growing 
<<ver Hevea from these hosts but not from original infections. Oryc- 
\us botryostachys is of considerable importance on the avocado. 
Since these trees are frequently planted in a^ociation with Hevea 
it is not surprising that some of these mistletoe.- are occasionally 
transferred to the latter. They are not. however, the species 
usually found on Hevea. and when they do occur it is probably the 
result of an accidental infection. 
Seven species of mistletoe were found on Hevea. They are I> - 
drophthora poepplgii (D. heveicola ITe ) (PL XIX), PI Iron 
rra-<s?fo 7 h//n (PI. XX), Oryctanthus botryostaehys (PL XXI). 
m adenostemon (PI. XXII). P. pyrifolia (PI. XXIII. A), 
P. amazonenzk (PL XXIV). and P. brasUiensis (PL XXV). The 
last two are believed to be new to science. 
Of these seven species Dendrophthora poeppigii may be considered 
the typical mistletoe of Hevea. It was constantly confined to this 
host and was the cause of considerable damage in several parts of 
the valley. This mistletoe, with its pinkish red berries and greenish 
yellow leafless stems, is very conspicuous on Hevea. and more 
pecially so during the period of leaf fail (PL XXVI). The species 
resembles some of the leafless Phoradendrons. It was originally de- 
scribed by Die as Dendrophthora heveicola. 
In his original report on the Amazon Valley. Akers evidently 
refers to this species and states that "in many districts a parasiti- 
cal growth not unlike mistletoe was found on the trees, and th 
difficult to eradicate owing to its growth on the upper branches 
where it can not be reached with ordinary appliances." Referring 
to this species Akers later states — 
This pest is found throughout all sections of the Amazon Valley. Its 
effects are most apparent on old trees, and from these ii draws out all the 
vitality, until branch after branch dies away and the tree i< killed. It has 
most tenacious roots, spreads rapidly once it has established a footing, and 
i< often propagated from seeds dropped by birds and lodging in crevi. • 
the bark or in joints where moisture has collected. * * * In every dis- 
trict the annual loss from this plague amounts to many thousands of ti\ 
