114 STATE BOARD OF AGRICULTURE. 



supposed!}' been weakened by fruit bearing, is thought by some to be 

 very injurious. 



The third lot of plants will be grown in double hedge-row. A few 

 of the most desirable plants will be staked. Runners from these will 

 be separated from the mother plants as soon as they appear and rooted 

 in the cold frame. These plants will be used to plant a propagating 

 bed. The}^ will be allowed to form runners at will, and these will be 

 used for the larger commercial plantings of another year. If the ex- 

 periment is to be conclusive, this sequence should be maintained, with 

 each of the three lots of plants, for at least five generations. 



Lettuce Diseases. — Last January the horticultural department re- 

 ceived from several greenhouse lettuce growers of Grand Rapids 

 samples of diseased lettuce. This was determined by Prof. R. H. Pettit 

 to be Marsonia perforans, a fungous disease that has been quite serious 

 in Ohio. A conference of the Grand Rapids lettuce growers was called 

 by Mr. Gunson and plans laid -for experimental work. It soon de- 

 veloped that other diseases, especially the ''rot" or Botrytis are often 

 very troublesome in Grand Rapids houses, and that the whole matter 

 of culture, especially of watering must be investigated. Experiments 

 were conducted in the college greenlwuses and in the greenhouse of Mr. 

 F. M. Strong of Grand Rapids, who has very kindly assisted us through- 

 out the experiment. Both of the experiments were supervised by Mr. 

 Gunson. « 



The experiment to control the lettuce diseases at Grand Rapids, 

 briefly, was directed along three lines: First, to sterilize the soil 

 through lines of drain tile sunk fifteen inches below the surface; second, 

 to water the soil through lines of tile similarly placed, thus avoiding 

 surface watering, which is conducive to disease; third, to manufacture 

 an artificial soil that will hold enough moisture to carry out a crop 

 without being watered while it is growing, similar to the famous Boston 

 lettuce soil. Two crops of lettuce were grown on plats prepared for 

 the above treatment. We are not yet prepared to report conclusions 

 from the experiments, except to say that the great problem is that of 

 watering. A practical method of watering below the surface the light 

 porous soils of Grand Rapids lettuce houses Avould wonderfully reduce 

 the amount of rot, rust and other diseases that injure the crop; to 

 this end the experiments of another season will be shaped. At the col- 

 lege lettuce was grown on soil from Boston and from Grand Rapids 

 lettuce houses, and also on several specially prepared soils containing 

 varying amounts of humus and sand. The results were striking and 

 will be of service to us in the work of another year, but we cannot make 

 much headway in this work until we have a lettuce house with a ground 

 bed similar to the Grand Rapids houses. At present only a raised bed 

 and a bench are available. The magnitude of the lettuce interests in 

 the state — 1,000 tons of lettuce were shipped from Grand Rapids alone 

 last year — make it desirable to give close attention to the problems of 

 these constituents. Plans for next winter's work on lettuce are already 

 under way. 



During the year four of my students have done some very creditable 

 experimental work which will be available for publication at some time. 

 Mr. C. G. Woodbury, on "Methods of Spraving for the San Jose Scale;" 

 Mr. M. J. Dorsey, on 'The Cold Storage of Fruits;" Mr. T. H. McHat- 



