PRICKLY PEAR IN U.S.A. 
who had found an additional difficulty in using Prickly Pear as a source 
of alcohol, viz., the existence of an organism or something in the te 
which inhibits the growth of yeast. 
With regard to the possibility of getting the upper hand of the 
pest pear in Australia, he offered considerable hope that the wild 
cochineal insect might be of use. When I told him that it attacked 
QO. monocantha in Queensland, but not O. inermis, he seemed surprised. 
He stated that this insect existed all over the United States where 
Prickly Pears grow, and does very considerable damage, although it 
never completely destroys the pear. 
At Chico, in California, they have a wonderful collection of Cacti 
growing on about 8 acres of land. Very few of the varieties are not 
attacked by the wild cochineal insects which threaten to destroy the 
plantation. Indeed, regular spraying has to be adopted to preserve 
them. More than 100 species are attacked, including Opuntia inermis 
—our common pest pear. 
The reason doubtless is that the usual American species is Coccus 
confusus, not C. indicus. 
The probable reason why the wild cochineal insect does not exter- 
minate the pear in its natural habitat is that in places like Southern 
Texas when rain does come it falls in torrents, thus checking the insect, 
which likes dry weather. 
Asked whether he had any experience of crossing different varieties 
of Prickly Pear (a matter of great importance in connexion with one 
possible line of attack on our pest pear), Mr. Griffiths said that he had 
not, but that, although natural cross fertilization is very rare, undoubted | 
hybrids had been produced. 
Some fuller information. is Sonne in the latest publication of the 
United States Department of Agriculture on the subject, Prickly Pear 
as Stock Feed, by David Griffiths, enclosed. 
The net result of my fice limited inquiries seems to 8 that 
there Is no great hope from the utilization of the Prickly Pear as 
stock food by concentration or desiccation, but that more attention 
‘should be given to the plant in its natural state as a reserve for drought 
periods in “the districts where it already exists, and that, where neces- 
sary, methods (such as singeing of the prickles) should the adopted to 
make it more attractive and less harmless to stock. 
Incidentally two’ very interesting points in connexion with its pos- 
sible extermination in Australia have been pointed out, viz. :— 
1. That there already exists at Chico, Galeowst, a race of the 
wild cochineal insect which is capable of doing serious 
damage to our common pest pear (Opuntia inermis), and 
other species, and 
2. That undoubted hybrids of the genus Opuntia have been 
' obtained. 
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