ROSE 



ROSE 



3017 



dependent upon the condition of the plants and the 

 weather. It is the custom to ventilate freely on bright 

 sunny days, and to guard the plants against draughts, 

 which invites mildew. To obtain the maximum amount 

 of growth, it is advisable to allow the temperature to go 

 above the normal 70 day temperature in bright 

 weather, giving ventilation at the same time, but not 

 sufficient materially to lower the house-temperature. 

 Careful ventilation at night in the summer, and the 

 keeping of a certain amount of fire-heat to dispel damp- 

 ness does away with black-spot, which disease of the 

 foliage is favored by the condensation of dew or mois- 

 ture on the plants during the night. Just how to check 

 black-spot is the hardest problem of the rose-grower. 

 Increased temperature with some quick-acting fer- 

 tilizer and allowing the 

 house to run warm on 

 bright days will often 

 check the disease by 

 inducing quick growth 

 and rapid sap-circula- 

 tion, giving the plant 

 the new foliage to re- 

 place that lost. When 

 the black T spot is per- 

 sistent, pruning back 

 the plant and allow- 

 ing it to start again 

 with clean foliage may 

 be the only way of 

 eradication. Black- 

 spot occurs on the 

 Hybrid Tea varieties 

 and, as few pure Tea 

 roses are grown, prac- 

 tically all greenhouse 

 varieties are subject to 

 this serious fungus. 

 Spraying with copper 

 solutions will help to a 

 certain extent in check- 

 ing it. See the special 

 discussion of this and 

 other diseases, page 

 3019. The question of 

 temperature is depen- 

 dent upon the variety 

 grown, but the normal 

 is 60 at night, 70 on 

 bright days, 65 on 

 dark days. 



Mildew is a fungus 

 which also attacks the 

 foliage, giving it a 

 dusty appearance and 

 curling the leaf. It 

 also appears on the buds, and, if not controlled, will 

 ruin an entire house. It spreads rapidly when once 

 established. Dusting the plants with flowers of sulfur 

 will kill the fungus if applied on bright days, but fumes 

 from the evaporation of the flowers of sulfur on the 

 steam-pipes will eradicate it much more effectively. 

 Mildew is induced by poor ventilation. Plants should 

 be so grown that the foliage, by constant fresh air, is 

 kept hard and mildew-resisting. A draught from a door 

 or broken glass will bring mildew. \Vhen the first sign 

 appears, kill the fungus and prevent it from spreading. 



The rose-midge (Neocerata rhodophagd) is the worst 

 pest which the rose-grower has to combat, but for- 

 tunately this insect has been known to exist only in a 

 few localities, and, to a considerable extent, only in 

 the rose-growing section near Chicago. It is micro- 

 scopic and is recognized first by its effect. The female 

 deposits its eggs beneath the sepals of the flower-bud or 

 between the folded leaves of the leaf-bud. The egg 

 period is two days, and the maggots, as soon as hatched, 



3485. A forcing Tea rose. 



begin to attack the buds. The maggots reach maturity 

 in seven days and then drop to the ground where they 

 pupate and the adult fly emerges six weeks later. As 

 the damage to the plant is done by the maggot which 

 eats the petals, the work of the midge does not affect 

 the growth of the plant, but the buds fail to develop, 

 usually dropping off after being attacked by the mag- 

 gots. Overgrown plants that do not flower are indica- 

 tions of its presence. The seriousness of the pest is 

 apparent and no precaution is too great to prevent the 

 rose-midge from getting a foothold. Buy plants that 

 are grown in sections not affected. Keep the houses 

 absolutely free from rubbish, both outside and under 

 the benches. If the work of the insect is apparent, get 

 rid of plants and soil in the house and grow other crops 



for a season, and start 

 afresh, which is the sa- 

 fest and best plan. See 

 the specialist's account 

 by Crosby, on p. 3018. 

 The rose is subject to 

 the attack of a nema- 

 tode, or eel-worm, 

 which infests the roots. 

 The use of Manetti for 

 grafting purposes has, 

 to a large extent, re- 

 lieved the rose-grower 

 of this trouble, for the 

 Manetti root does not 

 suffer from the attack 

 of nematodes; the use 

 of lowland soil is also 

 a safeguard. Steriliza- 

 tion by means of steam 

 will render soil safe and 

 its usefulness is not. 

 impaired, but this is, as 

 a rule, unnecessary. 



Rose-galls are a 

 bacterial disease which 

 cause growths on the 

 plants, varying in size, 

 and usually brown in 

 color. These appear at 

 the joints or where cuts 

 have been made. Re- 

 move these at once and 

 do not cut them open 

 with a knife used for 

 cutting flowers, be- 

 cause the infection can 

 be carried to the other 

 plants in this manner. 

 Cut off the affected 

 branch and burn it. 

 Thrip is an insect which attacks the leaves and petals. 

 It is small and its work usually can be recognized by 

 the white lines on dark-colored flowers, showing where 

 the surface has been eaten. Green-fly is a sucking 

 insect which attacks the new growths. Both can be 

 readily killed by the evaporation of nicotine prepara- 

 tions upon the steam-pipes, this having almost entirely 

 replaced the burning of tobacco-stems. 



Feeding the plants is accomplished by top-mulching, 

 or by liquid fertilizer, or by using both. Aside from 

 bone-tankage, few commercial fertilizers are in use, 

 cow-manure, well-rotted, clear or mixed with well- 

 rotted horse-manure, being more generally used. These 

 manures in liquid form may be used to advantage. Feed 

 light and often is the rule when plants are well estab- 

 lished. 



Watering depends on crop-condition. Water copi- 

 ously when the plants are coming into bearing. Water 

 less when the crop is being cut, and sparingly after the 

 crop is cut and before the new growth starts. 



