Vol. LIX. No. 2636. 
NEW YORK, AUGUST 4, 1900. 
fl PER YEAR, 
THE DESTRUCTIVE GREEN PEA-LOUSE. 
NEW FACTS ABOUT THE INSECT. 
Prospects for the Future. 
IT IS WELL ADVERTISED—Perhaps no insect in 
recent years has attracted more attention than the 
destructive Green pea-louse. It became conspicuous 
first on account of its ravenous attacks upon peafields, 
a crop heretofore practically immune from the rav¬ 
ages of insects, and secondly from the fact that it was 
a species not recorded in science. What condition in 
nature was responsible for such a general distribution 
of a new species of insect the writer will not attempt 
to discuss in this short paper. It appeared last year, 
and was recorded for the first time, from Maine along 
the Atlantic coast southward to North 
Carolina, and westward to Wooster, 
Ohio. It was also observed in Nova 
Scotia and Ottawa. Canada. During 
the past few days I have had it sent 
to me from Massachusetts and Ver¬ 
mont, and complaints of its serious na¬ 
ture have come to me from Chillicothe. 
Ohio; Long Island, New York, and por¬ 
tions of New Jersey. I first observed 
the pest May 18, 1899, and have had it 
under constant observation from that 
date to the present writing. I de¬ 
scribed the newcomer in the February 
issue of the Canadian Entomologist as 
Nectarophora destructor. A very long 
name, I admit, but if there is anything 
in a name being a burden to its pos¬ 
sessor, we hope that this one will ac¬ 
complish such a purpose. 
A PEST OF CLOVER.—From the 
first, I have held that this insect is 
probably a clover pest. It has been 
observed upon both Red and Crimson 
clover, and this season hundreds of 
acres of Red clover have been de¬ 
stroyed 'by it. In one instance, re¬ 
ported to me June 13, Mr. C. Silas 
Thomas stated that the pest had al¬ 
most entirely ruined 65 acres of Red 
clover for him. Many other cases of a 
similar nature were reported or ob¬ 
served by us. The attack has been 
very common upon Crimson clover 
also; but I have not heard of a field 
being killed by it. That clover, and 
perhaps the Red clover, is its original 
food plant, seems quite conclusive from 
our experiments and observations, i 
am of the opinion that Red clover is 
its original food, and that it is, there¬ 
fore, primarily a clover pest. Without 
doubt it is a native American insect, 
and has spread its attacks to Crimson 
clover and field peas, as these two 
plants have encroached upon the feed¬ 
ing ground of the louse. It spends the 
Winter as an adult in clover fields. 
REMARKABLY PROLIFIC—It is barely possible 
that this insect has other food plants, and lives over 
Winter upon them, but clover is, no doubt, the main 
plant upon which it lives. Mr. C. H. Chittenden, of 
the United States Department in Washington, ob¬ 
served this insect, or one very closely allied to it, 
feeding upon a number of species of vetches in Wash¬ 
ington this year. From a long series of experiments 
here in the laboratory, we have shown that there are 
two kinds of females known at present, the winged 
and wingless forms. No male has as yet been dis¬ 
covered, and pertiaps, in the South, none exists, and 
the insect remains over Winter in the adult stage, as 
stated above, upon some plant, and in most instances 
this is clover. The female produces living young 
which reach maturity in from 10 to 15 days, and pos¬ 
sibly less time in hot weather.. As an example, the 
young born March 4 reached maturity (winged form) 
March 16, or 12 days from time of birth, and was 
producing living young on March 19. From March 19 
to April 17 it became the mother of 111 young, and 
died on the latter date. Her first young (wingless 
form) born March 19, reached maturity and was pro¬ 
ducing on March 31, or 11 days from time of birth. 
From March 31 to April 13 she gave birth to 120 
young, and died. We have made many other observa¬ 
tions of a similar character, but this will suffice to 
show the rapid reproductive powers of this insect, 
and we might state that in many instances where this 
insect was first observed May 1, three weeks later 
tne fields were abandoned on account of its attacks. 
Calculating the number of insects produced per day, 
in six weeks one would become the mother of 423,912. 
WHAT TO DO.—It was estimated last year that 
the total loss from the attacks of this creature along 
the Atlantic coast States was $3,000,000, and that the 
crop was estimated at only one-half the usual out¬ 
put. From close communion with the largest grow¬ 
ers, the most experienced seedsmen, and most exten¬ 
sive business men in this line of business. The Trade, 
a canned goods journal published in Baltimore, has 
gathered the information that the crop of peas of the 
Atlantic coast this year will not exceed, on the out¬ 
side, one-third of what it was last year. This is 
about as serious as it can be, when it is taken into 
account that it is mostly due to this one pest, and 
that it is certain to increase its destructive powers 
from year to year, unless some factor in Nature in¬ 
tervenes to check and retard its further development. 
With this condition of affairs, it is not strange that 
farmers have become thoroughly discouraged, and 
make the statement that they will be more cautious 
about planting peas for market purposes or for the 
packer in the future. With this year’s experience, 
however, we have shown conclusively in our experi¬ 
ments and practical work in the field, that tihis in¬ 
sect can be kept in control to a very great extent, if 
taken in hand in time. In the first place, the peas 
must be planted in rows 24 or 30 inches 
apart, and not broadcast or in drills, 
as has been the case over a wide area 
throughout many of the Southern 
States. As an illustration of this, we 
might cite an instance on the place of 
Mr. C. H. Pearson, a large packer of 
Baltimore. His 600-acre pea planta-' 
tion was practically saved by persist¬ 
ent and energetic efforts on his part 
this season. All the methods from a 
practical standpoint were tried on this 
place, and it was found that the brush 
and cultivator method was the most 
effective. Forty men were therefore 
engaged to work in the field, and the 
600 acres were brushed and cultivated 
every third day for a period of two 
weeks, and in this manner the entire 
field was saved, netting the owner 
from 25,000 to 30,000 cases of peas of 
two dozen each. It is a fact which is 
not questioned by those who are famil¬ 
iar with this plantation, that had not 
this persistent and energetic fight been 
followed, the greater portion of the 
peas would have been destroyed by the 
insect. Last year the peas over the 
same area were broadcast, so there 
was no opportunity of fighting the 
pest, and as a consequence, 480 acres 
were entirely ruined by it. This year, 
by changing the method, and by a new 
system of fighting the pest, the peas 
have been saved. Many other illustra¬ 
tions of a similar nature could be given 
where we have been following this 
method persistently in this State. 
BRUSH AND CULTIVATOR—The 
brush and cultivator method is a sim¬ 
ple one, and the implements for this 
method are shown in the accompany¬ 
ing illustration, Fig. 178, which repre¬ 
sents a field of peas which was saved 
by brushing and cultivating. We might 
state, however, that a field not far dis¬ 
tant from the one shown in the picture, 
where nothing was done, was totally 
ruined by the pest. A good pine switch is used to 
brush the vines backwards and forwards ahead of 
the Iron Age cultivator, drawn by one horse, and in 
this manner the insects are covered, and a very large 
proportion of them destroyed. The cultivation should 
not be repeated until the third day, as it requires 
usually something over 48 hours for the destruction 
of the adult insects, when covered with earth. On 
this plantation we also sprayed a large acreage to 
show the practical side of this work, and the outfit 
just ready to begin work is shown in Fig. 179. Suf¬ 
fice it to say that we have found that no spray can 
be used which can destroy a percentage of insects 
large enough to warrant the expense of the operation. 
BRUSHING AND CULTIVATING FOR THE GREEN PEA LOUSE. Fig. 178. 
A WHOLESALE SPRAYING OUTFIT IN MARYLAND. Fig. 179. 
