32 N. H. AGR. EXPERIMENT STATION. [Bulletin 163 



The facts discovered are of such a nature that only extended field observa- 

 tions for another season or two can determine accurately the precise variation 

 in the life history. These observations are now in progress and further work 

 next season will be planned in accordance with the new data. 



Arsenic on Fruit. 



As a result of the prevalence of the browntail moth in New Hampshire, 

 this department, with other entomologists in other states of New England, 

 has repeatedly found occasion to advise fruit growers to spray fruit trees in 

 August. This plan is, by all means, the most effective one for control of the 

 above insect. The question then arose as to the danger of poisoning human 

 beings through arsenate of lead adhering to the surface of ripe or nearly ripe 

 fruit. A related question concerned with the possible poisoning of live stock 

 allowed to graze beneath heavily sprayed trees. 



In the lack of accurate and sufficient data on this important subject, in- 

 vestigations were undertaken to provide definite information. Trees have been 

 sprayed with known amounts of material under various conditions and the 

 fruit picked at varying intervals. Through the Department of Chemistry 

 of this Station, determinations are now being made of the amount of arsenic 

 oxide remaining on the surface of fruit, foliage and grass. The results will 

 be ready for publication this winter. 



Insect Outbreaks. 



Early this year the department learned of an occurrence of chinch bugs 

 in large numbers in a section in the western part of New Hampshire. An 

 assistant was sent to investigate the outbreak and further studies were con- 

 ducted this fall. The occurrence of this insect in destructive numbers in this 

 locality is unusual. 



A remarkable occurrence of a peculiar, obnoxious beetle was reported by 

 one of the large summer hotels in the White Mountains and the circumstances 

 were sufficiently interesting and important to warrant investigation. Ap- 

 parently the only other recorded instance of a similar outbreak was in Cali- 

 fornia some forty years ago. This insect will be given further study. 



Tests of Insecticides on Sucking Insects. 



In connection with tests of chemicals on soil-inhabiting insects it is found 

 desirable to try the effect of promising materials on aerial insects that are 

 resistant to known materials of control. 



