79 



scatter at once in the Held where bugs are most abundant, using the 

 infection box only in case of extreme dryness or where additional material 

 is desired. 



A quite unusual attack has occurred upon potatoes by a species of 

 leaf hopper which, so far as I am aware, has never been destructive to 

 this crop in this locality. It first appeared upon early potatoes in the 

 fore part of July and in many fields caused an almost total loss of the 

 crop. Late potatoes suffered less either because of the changed condi- 

 tions of weather or the movement of the insect to some other crop. 

 The insect agrees in every particular with the JEmpoa albipicta as 

 described by Forbes, but I believe this species is really an Empoasca 

 and to be referred to the mail of Le Baron. That it may live quite as 

 freely on potato as other plants is shown by the fact that larvse 

 developed there. An experiment with kerosene emulsion showed that 

 \yy using four nozzles and a strip of board to drag the tops of the vines, 

 so as to expose the under surface of the leaves and also to cause the 

 insect to fly into the air, a large proportion could be destroyed. In this 

 way it is believed we greatly benefited the field experimented upon. 



Scale insects have naturally received considerable notice on account 

 of the apprehension that the San Jose scale may at any time appear 

 within our borders. Thus far there has been no appearance of this pest 

 in the State, though I have on many occasions examined specimens that 

 were supposed to be of this species. The most interesting of the species 

 that has come under my notice in this connection is the Aspidiotus 

 rosce, which caused quite serious destruction to roses and some other 

 garden plants in Muscatine. The species has not been observed in the 

 State hitherto, but seems to have become quite a serious pest in that 

 locality. 



The hickory bark-beetle (Scolytus 4-spinosus) has caused considerable 

 damage in some localities and attracted attention particularly by the 

 destruction of foliage, due to the cutting of the adults into the petioles 

 of the leaves. 



While this injury attracts much more immediate attention than the 

 work of the larvse in the bark, there can be no question but that where 

 it occurs there is a certainty of the further injury which the larvae will 

 occasion by their operations. 



The Hessian fly (Cecidomyia destructor) has made its appearance in 

 the State, and so far as I am aware this is the first season that it has 

 been recognized or in which it has occasioned noticeable losses. If it 

 has been present hitherto it has been in such limited numbers as not 

 to attract attention, or at least not to be reported to the station. Its 

 principal center of injury at present appears to be in Buena Vista 

 County, which is in the northwest part of the State and one of the 

 spring-wheat counties. 



A point which is of interest as well as of particular significance to 

 the wheat growers is that its parasites seem to have occurred with it 



