422 OHIO EXPERIMENT STATION: BULLETIN 214 
We have found in Ohio that serious leaf-curl comes when cool weather, with 
frequent rains, prevails during April, May and June. It is to the April weather 
that the most serious trouble seems attributable. With low temperatures and 
frequent rains during the early half of this month we may safely predict an 
outbreak of leaf-curl (Bulletin 92). During such weather the fungus develops 
rapidly and the new leaves are affected as they are protruded from the bud._ In 
a modified sense the same takes place during May and in a still more limited 
sense during June. Successful prevention of leaf-curl is secured by thorough 
early treatment with Bordeax mixture. Indeed, it appears that a spraying at 
any time shortly before the blossoms open is several times more effective than 
any application afterwards. It appears that more effective results are secured 
by spraying two weeks before blossoming than immediately before the blossoms 
open. In any event an application made just before the blossoms open is more 
effective than at any later date’ Jime-sulfur applications for scale insects are 
effective to prevent leaf-curl. Whale-oil soap has also proved effective applied 
at this time, though not safe at much earlier dates. It is more expensive than 
Bordeaux mixture. (See Bulletins 104 and 148). 
Leaf-Spot of the peach may be due to a variety of causes and in no cases 
studied have they proved destructive. One fungus (Cercosperella persica Sacc.) 
is often mentioned. These leaf-spot are illustrated and very briefly discussed in 
Bulletin 92. a , 
Pustular Spot of the peach is a disease referable to a minute fungus (Helmin- 
thosporium carpophilum Lev.) which is apparently spread by spores that alight 
upon the upper surface of the fruit, flourish there and produce minute, light- 
brown spots, often surrounded by an angry red border. The red border is con- 
spicuous in earlier varieties and is sometimes elevated and pustular in appear- 
ance. This fungus greatly disfigures the fruit and is very easily prevented. 
Three applications of Bordeaux mixture have reduced the amount of pustular 
spot to less than one percent; whereas unsprayed trees gave more than sixteen 
percent of spotted fruit, much of which was seriously damaged. (Bulletin 92). 
Powdery Mildew (Sphaerotheca pannosa (Wallr.) Lev.) sometimes attacks 
peach in our state, but rarely with serious results. The attacked leaves some- 
times turn white and are sometimes distorted. Spraying with potassium sulfid 
or self-boiled lime-sulfur would be successful. : 
Rot or Brown-Rot. The brown-rot fungus (Sclerotinia (Monilia) fructigena 
(Pers.) Schroet) isamong the most destructive of the fungi on the peach, yielding p lace 
only at times to leaf-curl. Unlike leaf- 
curl the brown-rot prevails during 
warm, showery weather, and withsucha 
weather period is likely to occur at any 
time of the year. In April, ifthemummy 
peaches are permitted to remain on the 
trees from the preceding year, the fungus 
may affect the twigs through the blos- 
soms and thuscauseserioustwig blight. 
Itisa matter of common remark that the 
branches upon which rotted peaches are 
found often perish from the effects of the 
rotfungus. The survival ofthe fungus in 
these ‘‘mummy’’ fruits and the produc- 
tion of ascospores from them are well 
proven. No one variety seems more sus- 
ceptibletorotthan others, althoughsome ne Rotted 2 — dried or mummy peaches 
sorts are more liable to ripen during Will pesdo- eos oe Perel These maeales 
rainy weather and then rot worse. The ‘howe — 
