222 



on that already recorded [see this Review, Ser. A, iii, p, 758]. Its 

 object was to determine the difference in the egg-destroying properties 

 of early and late applications of the same strength of miscible oils ; 

 the result obtained by applying oil during unsettled cold weather ; 

 the relative merits of different commercial products in weak and strong 

 dilutions ; and the accuracy of the previous season's investigations 

 It was found that the most important factor required in destroying 

 leaf-roller eggs was the existence of fine and settled weather for several 

 days following spraying ; continued rainfall for four days following 

 spraying destroyed the effectiveness of the oil. Two days of fine 

 weather followed by continued rains permitted incomplete control, 

 while seven fine days following application resulted in complete 

 control. In this set of experiments a single brand of oil was used, 

 so that variations in the penetration and killing properties, dependent 

 upon specific gravity of different oils, were eliminated. 



In the case of heavy oils, volatilisation and penetration are slow, 

 and sufficient time must be allowed before activity ceases in order 

 that it may accomplish penetration or sufficiently cover the eggs to 

 give the desired results. Emulsions made from eastern or paraffin- 

 base oils spread better than the western or asphaltum-base oils. The 

 addition of one to two gallons of liquid soap to 100 gallons of emulsion 

 greatly increases the spreading property of the spray. 



Observations were also made as to the value of maintaining light 

 traps during the egg-laying period. A tungsten electric-light trap 

 was used which caught as many as 600 moths in a single night ; 95% 

 of these were males ; 3% spent females ; and 2% female moths 

 containing eggs. This represented practically the average nightly 

 catch over a period of several nights. 



When miscible oils were used in the proportion of 6 gallons of oil 

 to 100 gallons of water after the fruit buds began to show, considerable 

 foliage injury was noticed, but the buds were not injured in sufficient 

 numbers to reduce the crop or to cause injury to the tree other than to 

 retard its development slightly. 



Childs (L.). Suggestions for the Control of the more serious Plant 

 Diseases occurring at Hood River. — Rep. Hood Ricer Branch Expt. 

 Sta.for 1916, Oregon Agric. Coll. Expt. Sta., Corvallis, Sta. Bull. 

 141, February 1917, pp. 28-32, 2 tables. 



This article includes a spray calendar for the control of insect pests 

 and diseases of apples. A table for the dilution of lime-sulphur at 

 different degrees Baume is also given. 



Childs (L.). Suggestions for the Control of the more serious Insect 

 Pests occurring at Hood Riyer.—Rept. Hood River Branch Expt. 

 Sta. for 1916, Oregon Agric. Coll. Expt. Sta, Corvallis, ^ta.. Bull. 

 141, February 1917, pp. 33-34. 



For the control of the leaf-roller [Cacoecia argyrospila] the use of 

 miscible oil (6 : 100) under warm, settled weather conditions only is 

 advised. If brown aphis is also present, this spray will be equally 

 useful ; but against the Aphid alone, nicotine sulphate (1 : 1200) added 

 to lime-sulphur solution (1 : 20) at 32° Be., should be applied when the 

 first leaves are unfolding on the fruit spurs. For woolly apple aphis 



