During the last of June, 1920, the Duke estate at Somerville reported the presence of numerous caterpillars feeding on evergreens. Upon examination they proved to be the larvae of the gypsy moth, long destructive in Europe and established in the New England area since 1889. It was found that more than an acre of blue spruces had been defoliated on the Duke estate. Thousands of old egg masses were present and caterpillars were swarming over everything. The insect was probably introduced in the egg stage on blue spruces imported from Europe and set out on the Duke estate in 1911. As soon as the infestation was discovered the Federal Bureau of Entomology placed a small force of scouts in the field and traced the trees sold by the Duke estate after 1911. Early in November, 1920, the Legislature made a special appropriation to fight the pest, and a congressional appropriation was made in the spring of 1921 for the same purpose.
Beginning in November, 1920, one hundred New England-trained scouts were put on the staff of the division and these men found that the gypsy moth was present in an area of about 175 square miles, with Somerville as a centre. In addition, a substantial infestation was found at Nendham and small infestations at Glen Rock, Wyckoff, Paterson, Madison, Elizabeth, South Orange, and Deal Beach. The badly infested area on the Duke estate was cut and burned, and the same treatment took place in Mendham. Thousands of egg masses were creosoted in the Somerville area. Nine trucks, each equipped with sprayers, were purchased by the state and used to spray arsenate of lead on all foliage along roadsides, in wooded areas, on estates, etc., in the infested area. In addition, banding material to trap caterpillars escaping the spray was applied wherever spread was likely to take place. The extermination work was conducted jointly by the State Department of Agriculture and the Bureau of Entomology of the United States Department of Agriculture.
By 1921 the scouting work had demonstrated that the infested territory covered 410 square miles, of which 175 were generally infested, and the remainder, lightly. After the limits of the area had been determined, a safety band from five to ten miles wide was scouted around the entire area. After the scouting had been done outwards, in concentric rings, from Somerville as a center, it was repeated again from the safety band back to Somerville. Everything likely to harbor egg masses of the gypsy moth was examined-trees, fence posts, rock piles, stumps, buildings, etc. The entire area was mapped and thoroughly inspected and checked by "trailers," men who went over the territory behind the crews in order to see if anything had been missed.
Whenever egg masses of the moth were discovered, they were painted with creosote and the trees on which they were found, together with others in their vicinity, were sprayed with arsenate of lead. In addition, these trees were banded with burlap around the trunks in order to trap pupating caterpillars that might have escaped the spray. These bands were examined regularly and the caterpillars beneath the bands were destroyed. Thousands of trees were also banded with sticky tree-banding material to prevent any caterpillars from crawling up the trunks and reaching the foliage. Partly dead trees, stumps, etc., along the Millstone River and the Delaware and Raritan Canal, which were difficult to scout, were cut down and burned. The scouting work was supplemented by putting out "assembling cages"—tin cans containing an attractant for male moths, attached to tree trunks, with a band of tanglefoot below—in order to find out if any colonies in the vicinity had been overlooked by the scouts.
This extermination work, consisting of organized scouting, creosoting of egg masses, spraying of foliage with arsenate of lead, banding, caging, etc., was continued faithfully year after year for 12 years. A headquarters office and shop were rented at Bound Brook, from which the field work was directed. The largest number of workers hired during the period was 423 during February, 1923. As the infestation was cleaned up the need for a large number of workers declined.
In 1920–1921 over 835 colonies consisting of over three million egg masses were found. By the end of the second year the number of colonies had been reduced to 216 (909 egg masses). By the end of the ninth year only one colony of two egg masses was located. During the next three years nothing was found and the twelfth year's work marked the end of Federal participation in what had been a successful cooperative job of exterminating the gypsy moth from New Jersey. The cost was as follows:
|Fiscal Year||New Jersey Expenditures||Federal Expenditures|
From the beginning New Jersey was fortunate in having the active, wholehearted cooperation of Alfred F. Burgess, in charge of moth work in the United States Plant Quarantine and Control Administration, and H. L. McIntyre, of scouting and extermination work. 1923, H. L. Blaisdell succeeded McIntyre, and Harold A. Ames was placed in charge of the work in New Jersey. Much of the success of the extermination work is attributable to the knowledge and management of Ames, Headlee and Harry B. Weiss, of the Division of Plant Industry, who worked closely with the Federal agency and participated in the over-all planning.
In order to protect the state's investment in the success of the project, a small force of state scouts, under the supervision of Harold A. Ames, has continued to operate. Since 1931-1932 these men have continued to scout former danger areas in New Jersey, as well as other parts of the state, and have put out and patrolled hundreds of assembling cages. As a result of their activities one new egg mass was found near Mount Freedom and 117 new egg masses in Niendham Township in 1932-1933. As the state had sold and given away its spraying machines, in order to spray these areas it was necessary to borrow a crew, machine, and arsenate of lead from Federal sources. In 1934-1935 male moths were caught in Mendham and Morris Townships of Morris County and one male moth in Pahaquarry Township on the Delaware River. The Morris County areas were sprayed and the Pahaquarry area was caged. In the following two years, WPA funds made it possible to employ from 60 to 160 scouts for work in Morris, Essex, and Union Counties and for destroying tree stumps in the Morris County area where moths had been found. In 1936-1937 one male moth was captured in Morris County, and in 1939-1940, one in Englewood Borough. In 1944-1945 another male was caught in Englewood Borough. These males were all trapped by the assembling cages. The areas surrounding these captures were all caged and thoroughly scouted for several years following, but with negative results. In view of the gypsy moth infestations in the nearby states of New York and Pennsylvania, in New Jersey it has been necessary to do considerable scouting and cage work each year in order to detect anything that might develop.