Fungous diseases of plants . erfect orwinter stage has been discovered for the fungus, but the fact thatthe spores will germinate after remaining in the laboratory dry forthree months indicates that the conidia of the fungus are prob-ably carried over winter on the mulch or debris on the beds. Itgrows very readily as a saprophyte, and may pass the wintergrowing on the dead stems and mulch on the bed. The fungusmakes its first appearance on the stems early in the spring, shortlyafter they are up, but the disease does not become destructive 1 FUNGI IMPERFECTI 307 usually before the middle or lat
Fungous diseases of plants . erfect orwinter stage has been discovered for the fungus, but the fact thatthe spores will germinate after remaining in the laboratory dry forthree months indicates that the conidia of the fungus are prob-ably carried over winter on the mulch or debris on the beds. Itgrows very readily as a saprophyte, and may pass the wintergrowing on the dead stems and mulch on the bed. The fungusmakes its first appearance on the stems early in the spring, shortlyafter they are up, but the disease does not become destructive 1 FUNGI IMPERFECTI 307 usually before the middle or latter part of the summer ; so that thetops are not often killed before the middle of July or the first ofAugust in New York. The parasite does not pass down into theroot nor does it induce rot of any kind in the roots. The generaleffect on the root of the plant is to reduce its growth, and proba-bly where the blight continues year after year the root will be soweakened that it will become subject to soil rots of various Fig. 139. Blight of Ginseng: a Severe Attack beginning when theLeaves were Young. (Photograph by H. H. Whetzel) Control. It has been clearly demonstrated that this disease maybe controlled by thorough spraying with Bordeaux mixture. Theapplication should begin early in the spring, as soon as the plantscome through the ground, and should be kept up throughout theseason every ten days or two weeks. It is particularly necessaryto spray the young plants frequently when they are coming throughthe soil in order to protect them from the primary infection. Ithas been shown that ginseng is able to stand a very strong solution 3o8 FUNGOUS DISEASES OF PLANTS of Bordeaux mixture, so that the ordinary strength may be usedwithout causing any trouble. In the case of the early sprayingsin the spring when there is apt to be cold weather, it has beenfound that plants will sometimes be injured by the Bordeaux. Ifcare is taken not to apply the mixture just before a hard freez
Size: 1739px × 1436px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookpublisherbostonnewyorketcgi
