504 STATE HORTICULTURAL SOCIETY. 



pests at this time. Nor need I refer to the fact that they are much more 

 destructive in years of great drought. I will, however, refer to a very 

 important discovery which we made last spring. We found that the kero- 

 sene and soap mixture which I have so often recommended and praised was 

 equally efficient in destroying the eggs about to hatch as in destroying the 

 lice. You all know that leaves attacked by these lice often curl up, and also 

 that the foliage is a great obstacle in the way of thorough work in spraying 

 any tree with a liquid. It is to be recommended then and urged that all 

 pomologists, gardeners and nurserymen learn the entire life history of these 

 pernicious sappers, and when a serious attack is threatened apply the kero- 

 sene and soap mixture early in spring just as the eggs are hatching. Wo 

 tried this last spring on snow balls, apple trees, etc., with excellent results. 



Right here I wish to refer to the able researches and valuable discoveries 

 of Dr. C. V. Riley the past summer. By careful and very arduous study he 

 finds that the hop plant louse, Phorodon liumnli Schrank, Aphis Mimuli of 

 most authors, exists on plum in late fall, during winter — as eggs — and in 

 early spring as agamic females and for the remainder of the season on the 

 hops also as agamic females. It seems that there are thirteen broods in a 

 year. The lice of the 12th brood have wings and fly from hops to plums, 

 and produce a l:3th brood of apterous sexual females, A part of the 11th 

 brood are males, and are late in maturing. These also wing their way in 

 merry mood to the plums, where the nuptials are celebrated, after which the 

 eggs are laid on the buds and in crevices, and under bark scales. These eggs 

 mimic the bark very closely. The first spring lice, like all to 13th brood, are 

 agomic females. This first brood — called stem brood — are a little larger, 

 probably more prolific and with shorter legs, antennae, and nectar tubes than 

 the other broods. Each of these agamic females produces about 100 young, 

 and average three per day. The 3d brood is winged and migrates from plum 

 to hops. When the lice continue from 3d to 12th brood as wingless 

 avouiporous females. When another winged generation is produced which 

 migrates from hops to the plums. 



It will appear at once that these discoveries are very suggestive. Do other 

 plant lice <io the same thing? Are winged lice special generations produced 

 to effect migration ? Will not destroying the lice on plum early entirely pre- 

 vent the destruction or the loss of the hoplouse ? Surely it will, unless, for- 

 sooth, there is some other tree or plant where the louse passes the winter 

 besides the plum. Again, we see here the value of my discovery that the 

 eggs and young lice are so easily destroyed. Lastly, we note what a field 

 there is here for study and experimentation, just within this one family of 

 insects ! 



The last insect I have to consider is one that has for the first time the past 

 summer attracted attention as an enemy. I shall call it the cornstalk borer. 

 It is a noctuid tuotn, which, both as a larva or caterpillar and as a moth, 

 much resembles the cutworm moths of the genera Agrotis and Uadena. In 

 several parts of Northern Michigan this insect did much damage in June, by 

 boring into the young cornstalk, and causing it to wilt and die. The larva 

 is faintly striped and of a sober color. Thi^ moth is known as Heli Atra, and 

 so far as I can learn has never appeared in this role of destruction before. 

 Thus each year brings some new enemy to our doors. 



If this insect passes through a similar life history to that of the cut- 

 worms we can doubtless bate it with poisoned herbage the same as we can the 



