44 MASS. EXPERIMENT STATION BULLETIN 441 



Carnation plants made equally good growth under all three methods of water- 

 ing. Flower production on the differently watered benches did not vary signifi- 

 cantly. Splitting of the blooms was not noticeably affected by the different 

 methods of watering. The plants grew and produced equally well in ground 

 concrete beds and in raised concrete benches. 



Roots of carnation plants grown under subirrigation methods do not penetrate 

 the gravel layer beneath the soil to any great degree. Examination of plants 

 carefully removed from such benches showed that the roots mat in a layer at the 

 junction of soil and gravel level, closely comparable to the condition that occurs 

 with roots of plants grown in clay pots. 



Observations of top-watered benches in commercial ranges where carnations 

 are grown show that, in comparison with subirrigation methods of watering, 

 carnation plants are in greater danger of being inadequately supplied with water 

 r&ther than of being over-watered, as most growers fear. This is particularly 

 true during summer months, early fall, and spring. 



Losses of plants from stem, root, or branch rots were not observed to be any 

 more prevalent under constant water level methods than in manual or automatic 

 injection systems ot watering. 



Sodium Selenate as a Red Spider Control. (Harold E. White, Waltham.) 

 The use of sodium selenate for red spider control by commercial flower growers 

 in the State continues to increase. This past year between 40,000 and 50,000 

 pounds of P-40 were used by carnation and chrj^santhemum growers in Massachu- 

 setts. The P-40 is granular superphosphate impregnated with 2 percent of sodium 

 selenate and is the popular form used since it can be applied to bench soils as 

 readil)' as fertilizer. Growers of bench crops have shown greater interest in 

 sodium selenate than growers of pot plants. 



A few growers of hardy chrysanthemums have tried sodium selenate for con- 

 trol of foliar nematode, a disease that has become more common in hardy chrys- 

 anthemum plantings outdoors. 



Experiments so far at Waltham have been confined to the use of sodium sele- 

 nate as a method of insect pest control from the viewpoint of commercial applica- 

 tion. From these tests certain information has been derived, and problems have 

 arisen that indicate a need for more detailed investigations. 



Rooting of Carnation Cuttings in Subirrigated Sand and Vermiculite. (Harold 

 E. White, Waltham.) Cuttings of ten varieties of carnations were used for 

 rooting tests in Vermiculite (mica), subirrigated and top-watered, and in sand, 

 subirrigated and top-watered. The J^-inch and 3^-inch grades of Vermiculite 

 were compared as rooting media, as were mixtures of sand and Vermiculite; but 

 appreciable differences were not distinguished in the use of the two sizes of 

 Vermiculite. 



When root formation on cuttings rooted under the different treatments is 

 evaluated in terms of excellent to good, the ratings in percentage of rooting are 

 as follows: sand subirrigated 71; sand top-watered 75; Vermiculite subirrigated 

 72; and Vermiculite top-watered 83. 



When all the rooted cuttings of a treatment are grouped together without 

 classification, the results are: sand subirrigated 77 percent; sand top-watered 90 

 percent; Vermiculite subirrigated 81 percent; and Vermiculite top-watered 90 

 percent rooted. 



The results of these tests show that a mixture of sand and Vermiculite when 

 top-watered produced a higher percentage of rooted cuttings than similar media 



