Ornamental Plants 407 



General Diseases 



Powdery-mildews. — For description, see p. 122. 



These diseases are particularly common on ornamentals un- 

 der glass or in the open. The following list comprises the hosts 

 on which they are most frequently found; Adonis, Alyssum, 

 Anemone, Aquilegia, Begonia, Berberis, Calendula, Chrysan- 

 themum, p. 420, Clematis, Coreopsis, Cosmos, Dahlia, p. 421, 

 golden glow, hawthorn, honeysuckle, lilac, p. 426, larkspur, 

 peony, phlox, p. 429, rose, p. 431, spirea, sunflower, sweet pea, 

 p. 435, verbena, p. 436, violet, Virginian creeper. 



In-door or out-of-door treatments are essentially those 

 given under rose mildew (p. 432). 



Cutting-bench and Seed-bed Diseases. — If plants in the 

 cutting-bench are wounded or weak they are subject to attack 

 by many fungi that could not injure them under normal con- 

 ditions. The chief point in preventing inroads by these fungi 

 is to keep the cutting-bench and seed bed in good sanitary 

 condition, i. e., proper degree of moisture and temperature, 

 well ventilated, and free from infestation by injurious fungi. 

 Soil and bench, if once infested, should be disinfected (p. 460). 

 No diseased refuse should be allowed to contaminate it. The 

 chief trouble in the seed bed is damping-off (p. 19). 



Stem-rot (Corticium). — See p. 21. Numerous plants 

 are affected, among them: Abutilon, Acalypha, Achillea, 

 Ageratum, Alyssum, Amarantus, Antirrhinum, Aquilegia, 

 Asparagus, Aucuba, Bartonia, Begonia, Berberis, Calendula, 

 Callistephus, Campanula, Celosia, Centaurea, Chrysanthe- 

 mum, Cineraria, Coleus, Coreopsis, Cuphea, Dianthus, 

 Eriobotrya, Erysimum, Euphorbia, Godetia, Gypsophila, 

 Helianthus, Hibiscus, Iberis, Impatiens, Iresine, Kochia, 

 Lathyrus, Lavatera, Ligustrum, Linaria, Linum, Lobelia, 

 Lychnis, Lythrum, Matthiola, Pseonia, Pelargonium, Petu- 

 nia, Phlox, Physalis, Piqueria, Platycodon, Portulaca, 

 Potentilla, Primula, Punica, Pyrethrum, Reseda, Richardia, 

 Ricinus, Salvia, Santolina, Schizanthus, Sedum, Seradella, 

 Silene, Stachys, Taxus, Telanthera, Verbena, Vinca, Viola. 



