24 MASS. EXPERIMENT STATION BULLETIN 369 



Damping-off was well controlled by 2 cc. formaldehyde (in 1 quart water) 

 per square foot of soil. There was no chemical injury when 4 cc. was similarly 

 used but control was good with 3 or even 2 cc. There was good control by 3 cc. 

 whether soil, before treatment, was dry or up to 50 percent saturated. Control 

 was as good when solutions were applied at 10° C. as when they were applied 

 at 55° or 60° C. 



A solution containing 4 teaspoonfuls formaldehyde per gallon of water was 

 applied to a row 5 inches wide, immediately after seeds (of sweet peas) were 

 sown. Final stands were much improved by 1 quart of this solution for each 

 2, 3, or 4 linear feet of row, with best results when 1 quart was applied to 3 feet 

 (cr 1 gallon, containing 4 teaspoonfuls formaldehyde, to 12 feet of row). 



Vinegar 215 cc. per square foot prevented damping-off without injury. There 

 was, however, injury to some species when 235 cc. was used. 



A 1-400 solution of commercial formaldehyde applied at the rate of 1 gallon 

 to 5 square feet of seedbed or 1.89 cc. of formaldehyde per square foot has proved 

 most useful in the control of damping-off of certain vegetables. The solution is 

 applied after the seed is covered with soil. This treatment has not been injurious 

 to the following vegetables: beet, celery, chicory, cucumber, eggplant, endive, 

 lettuce, Romaine, onion, pepper, spinach, tomato, and Swiss chard. The best 

 stands of crucifers have been obtained from the treatment of the seeds with zinc 

 oxide. Lettuce and Romaine frequently have done better with a 1-500 solution 

 of formaldehyde (1.51 cc. per square foot) and with the red copper oxide seed 

 treatment. The use of lukewarm water in making the formaldehyde solution is 

 desirable as a precaution against injury. This method of treating seedbeds to 

 control damping-off is considered an improvement over the addition of formalde- 

 hyde dust to the soil before seeding, or over the so-called improved or direct 

 method of adding 6 cc. of formaldehyde per square foot of bed and resting the 

 soil before seeding. This method and dilution (1.89 cc. of formaldehyde per 

 square foot) is safer and more practical in controlling damping-off of the Pythium 

 type. 



Control of Greenhouse Vegetable Diseases. (E. F. Cuba, Waltham.) It has 

 been conservatively estimated that about 555 tons of greenhouse tomatoes are 

 lost to production in Massachusetts each year as the result of the tomato leaf 

 mold disease, caused by the fungus Cladosporium Julvum Cke. The new Bay 

 State tomato, resistant to the disease (see previous report), has been released 

 for commercial production and has proved highly acceptable. Bay State is 

 characteristically Waltham Forcing but earlier and with rather freely branching 

 or racemose fruiting clusters, both features being derived from Lycopersicon 

 pimpincllifolium, one of the original parents and the source of resistance to the 

 disease. Since the original crosses in 1933, desirable fruit size and quality have 

 been added to Bay State by three subsequent crosses with Waltham Forcing. 

 The resistance of Bay State to this serious tomato disease has revived interest 

 in the growing of greenhouse tomatoes for the autumn and winter market and 

 incidentally will reduce substantially the cost of greenhouse management espec- 

 ially required in the growing of other varieties of tomatoes. 



Causes and Control of Decay of Winter Squash in Storage. (E. F. Guba, 

 Waltham.) The past season has been most favorable for high yields of squash 

 and good keeping. Only occasional occurrences of black rot, caused by My- 

 cosphaerella citrullina (Smith) Gross., and bacterial wilt rot, caused by Bacillus 

 tracheiphilus EFS., and rare instances of blue mold rot, caused by Penicillium 

 sp., have been noted. It has been determined that shrinkage from moisture loss 

 in storage, from harvest to February 1, is approximately 10 percent of the weight 

 at harvest. In the 1938-39 storage season the amount of shrinkage varied but 



