MONTANA EXPERIMENT STATION. 135 



INJURIES TO PLANTS OTHER THAN THE STRAWBERRY. 



It should l)c l)ornc in mind that this beetle, being a very general 

 feeder, nia}- dexelop into a pest of various other plants. As we 

 have mentioned under our discussion of food plants the larvae are 

 said to feed voracioush' on the roots of timothy grass. We may 

 therefore expect it to be very injurious to crops of timothy that are 

 planted in territory which it has invaded. There is nothing to as- 

 sure us that it will not seriously injure various other crops. 



NATURE OF ATTACK. 



The adult beetles feed on the foliage of the strawberry and the 

 larvae feed on the roots. In an old bed one or more years of age, 

 the injury done to the foliage does not appear to be serious but on 

 newly set plants in the sirring or early summer, the beetles come m 

 such num])ers, eating the foliage and boring holes in the stems, as to- 

 cestroy the bed before it gets a fair start. The experience of Mr. 

 "Williams lias been that during the first summer when the plants 

 were small and just getting started, here and there a plant would 

 be killed. The next summer more would die and in the third sum- 

 mer, at the time fruit is growing, many plants would die owing to 

 the large number of grubs at the roots. At the time the full crop 

 should be expected the bed may be so invaded that not more than 

 one plant in ten to twenty of those that were set out is left. 



The beetles cat irregular patclies out of the leaves as shown in 

 plate II, fig. 2. This is a newly set plant photographed in the 

 field. It is not uncommon to find from fifteen to thirty beetles 

 hiding about a single young plant. 



The larvae feed on the roots and kill the plants outright. A plant 

 that is dead or nearly dead from this catise has many of its larger 

 roots eaten off and is more easily removed from the earth than a 

 healthy one. The younger larvae appear to feed on the fine rootlets 

 some distance away from the crown of the plant, and as they groAV 

 older they work their way up the roots, many of them eventually 

 leaching the crown or dense masses of roots just beneath the crown. 

 I "have never found a larva of this species really imbedded in the 

 crown. They seem to prefer the more exterior parts just where 

 the roots arise. Where they feed, a powdery brown substance, 

 their castings, is to be seen. They also feed from the surface of the 

 lower part of the crown more or less completely girdling the plant. 



