42 2 



Minnesota Plant Diseases. 



Power pump, gear (Fig. 106), 216 



Predisposition and variation, 96 



factor in disease, 93 



general and special, 93 



kinds of 94, 95 



Preserves, molds on, 122 



Prevention of disease, 201 to 209 



and fertilizers, 206 



and state aid, 208 



and wound infection, 204, 205 



by spraying, 212 



curative metfiods, 209 



importance of localities, 205 



importance of knowledge, 203 



importance of co-operation, 203 



plant pathologist in, 203 



selection of varieties, 206 



work of farmer in, 204 



Prevention of dry rot, 250 



of spread in disease, 207 



of timber rots and tree 



diseases, 237, 238, 239, 240 



Primrose, evening, rust of, 385 



Proficiency in parasitism, 57, 58 



Promycelium of rust (Fig. 73), 159 



Prothallia, damping-ofif of, 383, 384 



Protomyces, sucker threads 



(Fig. 2), II 



Pruning, best time for, 205 



for apple scab, 352 



methods of cure, 209 



of trees and protection, 237 



wounds and treatment, 205 



Puccinia angustata, 391 



asparagi (Fig. 161), 318,319 



caricis, 39i 



chrysanthemi, 371, 372 



coronata (see rusts of 



wheat), 

 fraxinata, 217 



fusca, 390 



graminis (see rusts of 



wheat), (Fig. 73). i59 



menthas (Fig. 209), 317,318,393 

 pruni, 350, 351 



rubigo-vera (see rust of 



wheats), 

 sorghi, 292 



tanaceti (Fig. 206), 



373, 374, 375, 389 

 vexans (Fig. 73), IS9 



violse, 373 



Puff-balls and allies (Figs. 90 

 to 95), 153, 154, 181, 182 



common gemmed (Figs. 90, 



91) 181, 182 



earth-dwelling habit, 39 



fruiting bodies, 23 



hard skinned, . 183 



long stalked (Fig. 92), 182 



spore distribution, 28 



strands of, 16 



true (Figs. 90, 91). 184, 185 



underground, 184 



Pumpkins, downy mildew of, 334 

 Pump, barrel (Figs. 104, 105), 



213, 214, ^30 

 barrel, in action (Fig. 107), 217 

 bucket (Fig. 102), 211, 330 



complex type of spray (Figs. 



109, 110), 222, 224 



engine power, 232 



gear power, 231 



gear power force (Fig. 106), 



216 

 horizontal, 231 



knapsack (Fig. 103), 212, 230 

 requirements for, 230, 231 



Punk, 40 



formation of, 85 



Pseudomonas campestris (see 

 black rot of cabbage), 

 phaseoli, 342 



Pseudopeziza medicaginis, 309 



trifolii, 309, 310 



Pure cultures of crops and epi- 

 demics, 206 

 disadvantages, 205, 206 

 Pycnidium of wheat rust (Fig. 



74), , 161, 162 



Pyrenomycetinea;, 123 



(dung fungi), (Fig. 60), 136, 137 



(sphere fungi), 137, 138 



(honeydew fungi), 125 



Pyrola rust, 386 



Pythium debaryanum (Fig. 34), 



45. 77, 382, 383 

 intermedium, 383, 384 



Quack grass, ergots of (Figs. 



53, 155), 127,308 



Rabbits, agents of spore distri- 

 bution, 30 

 fungi on, 73 

 Radish, black rot of, 342 



