THE MONTHLY BULLETIN. 481 



time the viviparous females appear. These females give birth to several 

 vomig which are placed on the under side of the leaves surrounding the 

 blossom cluster buds. Those females do not all appear at once but 

 .scattered over a period of a month, some appearing late in November. 

 Winged male forms appear soon after the winged females and co]nilate 

 with the wingless females on the leaves. These females each develo]> 

 three eggs and apparently reach maturity in from ten to fifteiMi d.nys. 

 but no eggs are laid until late in November. 



It is very rarely the case that you can find these sexual females on 

 the leaves at the growing buds and equally as interesting to note that 

 the leaves around the fruit cluster buds on the fruit twigs where they 

 occur, remain on the trees long after tlie leaves at the growing buds 

 have dropped. 



Egg laying begins with the first hard frosts and these usually occur 

 from the middle to the last of November in this section. In 1912 the 

 first eggs were laid November 28th and in 1913 about November oOth. 

 This egg laying period lasts about a week and on individual trees may 

 be accomplished in almost a day. It is not uncommon to observe a dozen 

 females depositing on one limb of a badly infested tree at the same time. 

 The eggs are at first colorless, then turn light green to purple and finally 

 black, the complete change requiring nearly four days. 



Taking these facts into consideration we determined on a fall spray 

 which would destroy these sexual females before they laid their eggs. 

 The time for this application, November 15th to 25th, is also favorable 

 to the grower as it occurs just at the best possible opportimity, the 

 weather being usually good, the soil firm and hard, while at the time of 

 a spring application the weather is often inclement and the orchard too 

 soft to permit the use of a power outfit. During the fall of 1912 we 

 applied from one to four sprays to different trees beginning with 

 the first of November for the trees sprayed four times. The trees 

 sprayed once, the 29th of November, showed practically as complete con- 

 trol as those sprayed more times. In the fall of 1913 we sprayed only 

 once, but used several different materials, some of which proved ineffec- 

 tive and had a tendency to cripple the experiment. The last 50 trees 

 were sprayed on December 2d and some eggs had been laid, but in 

 spite of this a very fine control was obtained. The material used w^as 

 ■4 per cent crude oil emulsion. One other material distillate emulsion 3 

 per cent with black leaf 40, 6 ounces to 100 gallons, used on about 200 

 trees also gave good results. An application of 12| per cent crude oil 

 emulsion late in December gave as good control as our spring treat- 

 ment. For this fall our plans are to use the 12^ per cent crude oil 

 emulsion as near the 25th of November as convenient and by this means 

 not only catch the sexual females of the purple aphis but also the eggs 

 of green aphis, tussock moth eggs, San Jose scale, moss and anything 

 else that a general winter application would rid the tree of. 



The same spray gave most excellent results on prune aphis and brown 

 apricot scale last year, so we will use it again this fall. In the care of 

 prune trees this need not be repeated for three years, and possibly only 

 every other year in the case of apples. 



