. The American florist : a weekly journal for the trade. Floriculture; Florists. i8g4. The American Florist. 681. Scale f) iDcbes. CARNATION THE STUART AS SHOWN AT THE INDIANAPOLIS MEETING. same way, they present very much the same appearance, except that their color is an orange yellow and they are gener- ally quite opaque. These nodules repre- sent the females of the root nematode (Heterodera radicicola), which is the cause of the gall formation ontheroots. Within these females, which occur at all depths in the root, from the center to the surface, from which they may even partly pro- trude,
. The American florist : a weekly journal for the trade. Floriculture; Florists. i8g4. The American Florist. 681. Scale f) iDcbes. CARNATION THE STUART AS SHOWN AT THE INDIANAPOLIS MEETING. same way, they present very much the same appearance, except that their color is an orange yellow and they are gener- ally quite opaque. These nodules repre- sent the females of the root nematode (Heterodera radicicola), which is the cause of the gall formation ontheroots. Within these females, which occur at all depths in the root, from the center to the surface, from which they may even partly pro- trude, are to be found eggs measuring about .04 mm. by .110 mm. in all stages of segmentation up to the formation of the larval worm, which lies coiled within the egg membrane and other larvae which have already hatched and lie free within the mother. The characteristic feature of this worm is to be found in the curious metamorphosis of the old female into a quiescent, cyst-like body and her slight resemblance to the male, which after a short time resumes its original activity and then more nearly agrees with the larva and with other nematodes. Mi- grating from the old cysts from which they have escaped, the young make their way into other roots or other parts of the same root, attacking the young and tender portions, where they give rise to galls similar to those in which they were themselves born. So far as I know this Heterodera was first noted as occurring in North America by the writer, in the Cou?ii>y Gentlemait for 1885, when it was reported as caus- ing galls on the roots of the clematis. It has long been known in Europe, how- ever, and in South America, and is the cause of serious diseases in a considera- ble number of cultivated plants, among others the coffee. A closely related, if separable, species is also destructive to the sugar beet in Europe. Within the last few years the root nematode has been made the subject of several important studies in this country, notably
Size: 1542px × 1621px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1880, booksubjectfloriculture, bookyea
