DISEASES OF PLANTS. 545 



Grenada to determine the cause for the low percentage of germination of the 

 seeds of Ilcvca brasiliensis. 



The investigation shows that all light seeds should be rejected in making 

 selections for plantings. Seeds which were kept in the air lost 6 per cent of 

 their weight in 2 weeks' time, whereas seeds packed in dried charcoal lost 20 

 per cent of their weight, the latter being about the extreme limit of desiccation. 

 The loss of weight appears to coincide with loss of germinating power and desic- 

 cation apparently takes place in some instances even before dehiscence of the 

 capsule. It appears that without special precautions Ilevea seMs will lose their 

 germinating power within 2 or 3 weeks after the ripening of the capsules. It is 

 considered important that no Hevea seed should be sold until it has been se- 

 lected rigorously by weight, nor should any unnecessary exposure or loss of 

 time in planting be allowed. 



Ceara rubber (Bui. Imp. Inst. [So. Kensington], 9 (1911), 'So. 1, pp. IS). — 

 Analyses based on examinations made by the Imperial Institute are given of 

 specimens of Ceara rubber from Ceylon, Uganda, East Africa Protectorate, 

 Nyasaland, Sudan, and Southern Nigeria. 



DISEASES OF PLANTS. 



Report of the botanist for 1909 and 1910, G. P. Clinton (Connecticut State 

 Sta. Rpt. 1009-10, pt. 10, pp. 113-11 ), pis. 6). — This reijort includes notes on dis- 

 eases in relation to weather in 1000 and 1910, new observations on diseases 

 previously reported, diseases or hosts not previously reported, spraying potatoes 

 in dry seasons, and a study of the formation of the oospores of potato blight 

 (Phytoplithora infestans). 



The following diseases were found to be prevalent or unusually severe during 

 1909: Black rot, rust, scab, and spray injury on the apple; rust on the ash; 

 bark disease on the chestnut ; wilt on the eggplant ; leaf spot on the elm ; leaf 

 mold and anthracnose on the muskmelou ; brown rot (on twigs) and loaf curl 

 on the peach ; black knot on the plum : tip burn and scab on the potato ; leaf 

 blight on the quince; rust on the rose; leaf mold on spinach; powdery mildew 

 and winter injury (to roots) on the strawberry; and calico on tobacco. During 

 1910 the following diseases were noted : Rust, scab, frost, and spray injury 

 on the apple ; black knot on the cherry and plum ; bark disease and drought in- 

 jury on the chestnut ; smut on corn ; rust on the hollyhock ; leaf scorch on the 

 maple; mildew blight on the muskmelon ; leaf curl and brown rot (of twigs) 

 on the peach; scab on the pear; pine-sweetfern rust on the pine; rot (blight) 

 and tip burn on the potato ; powdery mildew on rye and barley ; rust on the 

 quince; and anthracnose on the sycamore. 



It is claimed that successive droughts for the past 4 years have affected the 

 forest trees, especially pines and chestnuts, making the latter more susceptible 

 to the chestnut bark disease, and also that the unusual winter of 1904 seriously 

 injured the chestnuts so that the bark disease fungus (Diuporthe parasitica) 

 became actively parasitic. The uredq and teleutospore stages of Pucciniastrum 

 myrtilli (Pcridermiiim peckii), the hemlock-heath rust, is reported on various 

 species of blueberries and huckleberries. In discussing the so-called blight of 

 the white pine, the author claims that it is due primarily to adverse weather 

 conditions, such as winter, drought, and frost injuries. Specimens of D. para- 

 sitica have been collected on the Japanese chestnut (Castanea japonica) in 

 a local nursery, and are also reported on C. sativa and C. punvila. The pine- 

 sweetfern rust (Cronartium comptonice) is reported on Piniis rigicla, P. au- 

 striaca, and P. maritima. The pine-currant rust (Cronartium ribicola), which 



