IOWA ACADEMY OP SCIENCES. 
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destroying large numbers of young plants of Setaria 
viridis. In whole patches it prevented the maturing 
of seeds. 
Plasmopara Viticola (B. and C.) B. and DeT. 
Abundant. Destructive to cultivated grape (Vitis Labrus- 
ca), affecting leaf, stem and fruit. Also affecting the 
growing of young shoots of Vitis riparia, in some 
cases killing the young shoots. 
P. Halstedii (Parlow) B. and DeT. 
Not common, on Helianthus annuus, H. tuberosus, Silphium 
laciniatum, Xanthium Canadense, Centaurea. 
Bremia Lactucce Regel. 
Not observed although abundant in 1893. 
Peronosposa Vicice (Berk.) DeBy. 
Abundant in latter part of May and early June on Vicia 
Americana. 
P. Arthuri Parlow. 
Abundant on Oenothera biennis. 
P. parasitica (Pers.) DeBy. 
Abundant on leaves and stems of Lepidium intermedia, 
L. Virginicum, killing the affected plants. On leaves 
of Capsella bursa pastor is not destructive. Brassica 
nigra, B. campestris, Raphanus sativa, Draba Carolin* 
iana. Sisymbrium officinale seriously affected. 
P. Potentillce DeBy. 
Not found in 1895. Local in 1891. 
P. effusa (Grev) Rabenh. 
Abundant on Chenopodium album in May and June. 
P. EupliorMce Puck. 
Locally abundant on Euphorbia Preslii and E. maculuta. 
P. alta Puckel. 
Abundant on Plantago major. 
PERISPORIACEAE. 
Podosphcera Oxyacanthce (D. C.) De By. 
Abundant on cultivated (Prunus Cerasus) and P. pumila. 
Not common on P. Americana; also observed on young 
shoots of Crataegos punctata, and C. mollis; July, 
August and September. 
SpcBTotheca Mali (Duby) Burrill. 
Common on suckers of Pyrus Malus and young shoots of 
P. toringo in nursery, June, July and early August. 
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