396 



STATE HORTICULTURAL SOCIETY. 



arsenites. To test the possibility of poison being concealed between the 

 stems, a row of plants was sprayed with Paris green at the rate of one 

 pound to 175 gallons of water. Two weeks later a part of the same row 

 was again sprayed with the same. The plants then stood another week 

 when both lots were taken up, the roots, leaves, and green stems taken ofP, 

 and the remainder washed under the hydrant without separating the stalks. 

 The bunches were in this way prepared as they are for marke't. They were 

 then sent to our chemist for analysis. 

 His report is as follows: 



Agricultural College, Mich., Oct. 12, 1893. 

 Deae Sik — The specimens of celery sprayed with Paris green have been 

 analyzed by Mr. Harrison, and the quantity of arsenic (As, O3) determined 

 in a pound of C( lery. 



He finds the following quantities of arsenic in grains in one pound : 



No. 1, sprayed once .0244 grains 



No. 2, sprayed twice .0368 



Yours truly, 



R C. KEDZIE. 



This amount, Dr. Kedzie tells me personally, would not poison anyone 

 at once but the effect would be evident with frequent use. The poison 

 was freely applied, much more thoroughly than it generally would be, that 

 our information might be certain whether or no it might be recommended. 

 From the above analysis we can hardly recommend the use of any of the 

 arsenites to protect celery against insects and must resort to anti-poisonous 

 remedies. 



THE ZEBRA CATERPILLAR (Mamestra picta, Harris). 



Oedee LEPIDOPTERA. Family NOCTUlD.a;. 



A common zebra-like caterpillar that feeds on the leaves of celery. It is found occasionally early in, 

 the season but becomes more plentiful and often harmful later. 



Fig. 15— Mamestra picta in its various stages. A, cluster of eggs as seen 

 on a leaf; B, one of the eggs magnified, C, the young caterpillar; D, the 

 mature caterpillar ; E, the pupa ; F, moth. All natural size except the 

 single egg— (original). 



Though not so large, this caterpillar is even prettier and more striking^ 

 than the preceding "species. For the seasons of 1891 and 1892, this wa& 

 the most common celery pest reported to ue. Last year it was very com- 



