314 Report of the Horticulturist of the 



By formalin as used in this article is meant the 40 per cent 

 solution of formaldehyde gas. When purchasing, it is well to 

 ask for the 40 per cent solution of formaldehyde gas as it is 

 quoted much lower than the same material under the name of 

 formalin.* 



RECOMMENDATION. 



For holding the gooseberry mildew in check the Station recom- 

 mends potassium sulphide as the most effective remedy. It may 

 bie applied at the rate of 1 oz, to 2 or 3 gals, of water begin- 

 ning very early in the season, just as the buds are breaking, and 

 repeating about every ten days, depending, of course, upon the 

 condition of the weather. 



GENERAL APPEARANCE OF MILDEW. 



The mildew is a parasitic plant, or fungus, which appears on 

 the surface of the fruit and young shoots. When first noticed it 

 is composed of glistening, white threads which give it a frost-like 

 appearance. As the fungus develops the threads become more 

 niuimerous and matted, lose their glistening color and finally be- 

 come a mass of brownish felt-like substance. It has now com- 

 pleted its growth and ripened its winter spores and can usually 

 be peeled off the berries without rupturing the skin. 



If the attack is severe the tender young leaves and shoots will 

 be seriously injured, if not killed, and the growth checked. The 

 growth of the berries will also be checked and they are likely to 

 be misshapen and even to crack open thus letting in the germs 

 of decay. 



The spores by which the fungus is reproduced correspond to 

 the seeds in higher plants but are very much simpler in con- 

 struction. There are two kinds of spores, the summer sipores and 

 the winter spores. The summer spores (conidia) are formed on 

 vertical branches of the glistening white threads which make up 

 the fungus. As the vertical branch grows in length a partition 

 appears near the upper end. This partition soon cuts off all con- 

 nection with the Lower part of the branch and the upper part 



*De Schweinitz, E. A., Year Book U. S. Dept. of Agr., 1896, p. 262. 



