250 REPORT OF THE DEPARTMENT OF BOTANY OF THE 
The spraying was done very thoroughly with a knapsack sprayer. 
The bordeaux mixture used contained six pounds of copper sul- 
phate to each 50 gallons and lime considerably in excess of the 
amount required to satisfy the potassium ferrocyanide test. When- 
ever paris green was used it was applied at the rate of one-half 
pound to 50 gallons of bordeaux or of lime water as the case might 
be. 
Over the entire field bugs were brought under complete control by 
the two applications of paris green made July 9 and 24. Late 
blight (Phytophthora infestans) was wholly absent and early blight 
(Alternaria solani) appeared only in traces. There was some tip 
burn and a light attack of flea beetles (chiefly, Epitrix cucumerts). 
Up to September 1 there was scarcely any difference between 
sprayed and unsprayed rows. But during September a change came 
about — the unsprayed rows gradually turned brown and died while 
the sprayed ones remained green. ‘The reason for the longer growth 
of the sprayed plants is not altogether clear. Probably it was owing 
chiefly to the fact that the spraying protected the plants against flea 
beetle injuries. There being an abundance of rain after about Sep- 
tember 15 and no killing frost until October 17, the plants remaining 
alive had an exceptional opportunity for growth. Although planted 
so early as May 22 the sprayed rows still showed considerable green 
foliage as late as October 17 when the frost came. 
The potatoes were dug by hand. The product of each row was 
sorted into two grades—marketable tubers and culls— and 
weighed. No rotten tubers were found. The yields follow: 
TABLE XI.— YIELDS IN THE EXPERIMENT AT GENEVA IN 1907. 



YIELD PER ROW. YIELD PER ACRE. 
Row. TREATMENT. == a 4S 
Marketable. | Culls. Marketable. Culls. 
Lbs. Lbs. Bu. lbs.) Bulbs: 
] Sprayed o Cites. 2.25 te vs se eee 253 4 210 5013 20 
2). SS DLAYVeG. otimesey saree vee ens 301 1 250 50 50 
Sian eal CUNSDTAV EC." sae ony ena eae sd 202 4 168 20 j\°3 20 
An eo prayedio timesiin. aatektsee pane 238 3 198 20 | 2 30 
wicca MOOLA VEO) Oe tiiMes 2 ee mere tehaee all 290 3 241 40 | 2 30 
Sue) oe Umsprayed +..igyt ea tie eae | 2024 44 | 168 45 | 3 45 
lates LOLA Vesa: LIMES: .uee een ce 2524 2 210 PAs po Gh 40 
Src he Sorayed bitimest see ee ae 301 24° | 250 50 | 2 5 
Derren s UTIS PTA VOU coc. ctycnece se. oul et et 216 i 180 — {4 10 
LOMA -ODTAVedso Lithess pes ees 3044 13253 45m eh 15 
LA peat ODLAVECKOSIMEeS tee scene Son 1 252 30 50 
12 soa Uns pravecdics. 4 sake mane wee od 2134 PP oe pen Lele Layee | hae 5 
IS See ODIAVeOro Limes aren ieee eee 2735 | 14 | 227 DD see 15 
14; ea ‘Sora yed Bbatimes. 6 | ences 304 | Le a2bs 20 | 1 15 
15c. rt Unspra ved. sia coon «sie cing 40 tes Ms | 24 | 185 50 | 2 5 


— ee ee a 
Tt Rows 290.4 feet long by 3 feet wide makings the area of each row exactly one-fiftieth acre 
