30 PROTECTION OF PLANTS, 1918-19 



This is readily illustrated by an examination of the number of nests that were 

 found from year to year. 



Nests Collected in N.B. 



1911-12 1912-13 1913-14 1914-15 1915-16 1916-17 1917-18 1918-19 

 2,452 81 28,100 239 395 375 62 



The variation in the number of nests collected from season to season is 

 largely due to the geographic pcsition of the province in that it borders the state 

 of Maine and is in close proximity to the heavy infestations in the neighboring 

 New England states. If the meteorological conditions are favourable at the time 

 of the brown-tail flight in the latter areas. New Brunswick is reinfested. These 

 flights, fortunately, occur very irregularly. The heaviest invasion of moths 

 occurred in the summer of 1913. As a result of that flight eleven of the fifteen 

 counties of the province were infested and the total area of infestation covered 

 practically two thirds of the province. The following winter over twenty-eight 

 thousand winter webs were collected and it looked as if the brown-tail moth would 

 obtain a firm foothold. By employing a sufficient number of conscientious 

 scouts a serious situation was relieved. To this must be added, however, the 

 extreme severity of the winter which caused an unusually high mortality among 

 the caterpillars in the "missed" winter webs. 



From then on, the work progressed very favourably, the outside territory was 

 gradually cleared up and in 1917-18 only three localities were found to be giving 

 any definite amount of trouble. In all three districts the brown-tail was breeding 

 and in addition two of them were reinfested each year. Considerable difficulty 

 was encountered in clearing up districts where the snowfall was unusually heavy 

 and the winter nests were covered with snow. Experiments carried on at the 

 Fredericton Laboratory proved that the mortality rate among larvae in nests 

 covered with snow was extremely low, and that these nests which could not be 

 found by the scouts were responsible for maintaining an infestation which other- 

 wise could be cleaned up. 



The work in the province of New Brunswick has developed into a policing 

 and patrol system, and the number of scouts employed is reduced to a minimum. 

 If we do not get an overwhelming flight from the United States, no great difficulty 

 is anticipated in keeping the brown-tail moth well in hand in that province. 



The situation in Nova Scotia is very different from that of New Brunswick, 

 as the brown-tails were well established and breeding extensively before the Dom- 

 inion Government took over the control work. Furthermore, the climate through- 

 out the Annapolis Valley, where the worst infestation occurs, is milder, and more 

 favourable food plants both wild and cultivated are very much more common. 

 In fact the entire infested area in this province is ideal for this pest on account of 



