2 BULLETIX lOSO, U. S. DEPART:MEXT OF AGRICULTUEE. 



apparently hatched well would have shown considerable injury. Such 

 points, however, would only have been brought out by an intensive 

 study in the woodland, such as was started later. A few records of 

 entire clusters failing to hatch were made in 1907. notably in Xorth 

 Saugus. Mass.. in woodland near the building then used as a labora- 

 tory for the parasite investigations. 



During the winter of 1911-12 plans were perfected for an extensive 

 and intensive study of the gipsy moth under natural conditions. 

 These plans called for the selection of a considerable number of small 

 areas, well proi^ortioned as to type of tree growth and so placed as to 

 be representative of the entire infested area. The areas designated 

 as *• observation points " were to be followed closely during the entire 

 year, with careful notes on hatching of the gipsy-moth eggs, feeding 

 of the larvse and the injury done by them, the increase or decrease of 

 the infestation from year to year, and many other phases of the sub- 

 ject. As the entire problem was built around the degree of infesta- 

 tion, it became necessary to have an accurate knowledge of the num- 

 ber of egg clusters present in each " point.'' Therefore, each fall or 

 winter a careful count was made, and it was this counting which 

 brought forcibly to the attention of those engaged in experimental 

 work that some agency was playing a considerable part in the con- 

 trol of the moth by killing the eggs. 



The nonhatch problem did not receive extensive experimental at- 

 tention until the fall of 1915, when preliminary work was started. 



FIRST INVESTIGATIONS. 



At first considerable time was devoted to the study of the nonhatch 

 eggs themselves. Such individual eggs collected a few months after ' 

 the end of the normal hatching season, as well as those 1 or 2 years 

 old. were all light gray in color. Careful dissection showed that this 

 appearance was due to a complete, closely woven mat of fungus 

 mycelium which was pressed closely against the inside of the shell 

 and entirely surrounded the dead embryo. The presence of this 

 organism in all the nonhatch eggs made it appear that there might 

 be some connection between it and the death of the embryo. Cul- 

 tural studies were made, and a considerable number of infection experi- 

 ments were carried on. which, however, failed to give more than vague 

 evidence that the fungus was ever more than a saproph>i:e. It is 

 possible that this organism, belonging in the large and rather indefi- 

 nite genus Fusarium. is. under conditions particularly favorable to 

 itself, a true parasite. However, extensive dissections and cultures 

 made of nonhatched eggs as soon as it was shown that they were not 

 going to hatch have yielded no positive evidence of its being parasitic. 



The first real study of nonhatch in the field was l^egun in the fall 

 of 1916.^ Previous to this a series of egg-cluster collections had been 

 made, beginning in August. 1915, and continuing at monthly inter- 

 vals until just iDefore normal hatching time in the spring of 1916. 

 Six sets of these collections were made, five being obtained at chronic 



1 The writer wishes to express his appreciation of the able assistance given him by 

 Mr. H. I. Winchester, who helped with tlie experiments for almost the entire time they 

 ■were conducted. During the time the writer was in the Army, Mr. Winchester conductert 

 all the experiments, and to him belongs the credit for planning and making the summer 

 observations on hatching. 



