Fungous diseases of plants . may be affected, althoughthere is considerable difference in the degree of some of the berries most susceptible in the northeasternUnited States may be mentioned the Hunn and the BeederWood. Susceptibility of a variety varies, however, when culti-vated under different conditions. Marshall and Brandywine haveoften proved very resistant. 262 FUNGOUS DISEASES OF PLANTS The fungus. The life history of the fungus has been con-siderably studied, and it is probable that some spore stages whichhave been described are not at any rate common stages in th
Fungous diseases of plants . may be affected, althoughthere is considerable difference in the degree of some of the berries most susceptible in the northeasternUnited States may be mentioned the Hunn and the BeederWood. Susceptibility of a variety varies, however, when culti-vated under different conditions. Marshall and Brandywine haveoften proved very resistant. 262 FUNGOUS DISEASES OF PLANTS The fungus. The life history of the fungus has been con-siderably studied, and it is probable that some spore stages whichhave been described are not at any rate common stages in thelife cycle. In general, two spore-producing stages may be found,the conidial and the ascigerous stages. The conidial stage hasbeen described as Ravudaria Tulasuci. This appears in earlysummer, as a rule, or so soon as the pale centers of the spotshave been developed. Small, tuberculate stromatic masses areproduced upon the mycelium beneath the epidermis, and fromthese arise a small group of simple hyphae, which rupture the. Fig. 114. Leaf Spot of Strawberry epidermis and produce conidia which may become one or severaltimes septate. The conidia, according to Dudley, measure 20-40 X 3-5/^ (Fig. 115, n). The ascigerous stage is not so commonly found and is in nocase developed until late summer. A membranous perithecium,characteristic of this family, is then produced within the leaf, al-though at maturity a considerable part of the perithecium may beexposed. Relatively few asci are developed, the asci containinginvariably eight hyaline, uniseptate spores with acute tips (Fig. 115).It would appear that the spores are not ordinarily mature untillate winter, or at least not ejected until that time. Moreover, i
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