3(3 ixsi-:cTiciDES, fungicides, and weed killees. 



blue vitriol or immersion may be employed inditferently, as they both 

 give the same result. The millet seeds must be left seven and a half 

 to twelve minutes in water at 55° C. (131° F.). 



Ustilago Maydis, Corda (smut of maize). — Nijpels prescribes the 

 immersion of maize by Jensen's method ; it gives good results. 



Ustilaijo hroinivora, Fisch. (smut of brome grass, Dromus arvensis). 

 — According to Eostrup immersion has also been tried with success 

 against this disease. 



Sphaerella Tuiasnei, Junez (black of cereals, Cladosporium her- 

 barium). — Giltay prevented the development of this disease by 

 immersion in hot water. Kolpin Kavn prevented it entirely on barley 

 and oats by Jensen's immersion at 52°-53° C. (125-6°-127-4° F.) for five 

 minutes, after previously softening the grain for fifteen minutes in 

 cold water. 



Puccinia (rust of cereals). — The numerous experiments of 

 •Galloway in Amei'ica to diminish the rust of cereals by dipping the 

 seed for fifteen minutes into water heated to 56° C. (132'8° F.) have 

 not given the result anticipated. The treated seed gave as many 

 diseased plants as the untreated. That is due to the method of 

 development of the fungus, which does not appear, in fact, to propagate 

 itself through the seed. Immersion has also been used to prevent 

 beet diseases, due to fungi propagated through the seed. These diseases 

 are Pythium de Baryanum, Hesse ; Bhizoctonia violacea, Tul. (beet 

 Ehizoctone) ; Phoma tabifica, Pril. et Del. (disease of the petioles of the 

 leaves) ; Pleospora putrefaciens, Frank, (rottenness of the heart). 

 Jensen's method has given excellent results, and it follows from the 

 trials made by Hollrung that immersion, instead of injuring the seed, 

 on the contrary stimulates their germination. Treatment with cold 

 water greatly increases the germinative capacity of beet seed ; but 

 it must not be kept ninety days after immersion before sowing, 

 because the effect gradually disappears. If the seed be sown soon after 

 immersion an excellent result is obtained with very few diseased 

 plants. The procedure is as follows : The seed, in a wire-gauze 

 basket, is immersed for six hours in cold water, left to drain ten to 

 twelve hours in an airy place, then dipped for five minutes into water 

 heated to 53-5° C. (128-3° F.), taking care to dip and raise the basket 

 at regular intervals. Nothing further is required but to pass the seed 

 into a bath of cold water, and it may be sown at once, or after 

 standing for not more than ninety days. Summing up, Jensen's 

 method sometimes gives results inferior to treatment by blue vitriol, 

 because it scarcely ever diminishes the germinative capacity of 

 the seed treated ; it is only really prescribed for the disinfection of 

 seed-oats, for the results are undoubtedly superior. For all other 

 cereals blue vitriol, bouillie bordelaise, or potassium sulphide may be 

 prescribed. The latter process was recommended by Jensen himself 

 in 1895 (" Ceres " powder) as capable of replacing immersion. 



Immersion of Seed against Insects. — Phylloxera. — Balbiani's i*e- 

 searcties on resistance of phylloxera eggs show that non -rooted buds can 

 be treated preventively by one dip of five to ten minutes in water heated 

 to 45°-50° C. Experiments renewed in 1887 by G. Couanon, G. Henne- 



