REPORT OF THE STATE ENTOMOLOGIST I905 93 



Grass and grain insects 



White grubs (Lachnosterna species). White grubs of the 

 May or June beetle are well known and are more or less abundant 

 from year to year, though the insects have a life cycle extending 

 over three years and a corresponding fluctuation in injuries has 

 been observed. This season appears to be one when the grubs were 

 unusually destructive, as reports of serious damage have been 

 received from several sections of the State and one at least from 

 an adjacent state. 



The life history of this species may be summarized briefly as 

 follows : Eggs laid by the parent beetles in loose soil hatch about 

 a month later, the grubs slowly increasing in size for at least two 

 years and from the middle of June till the middle of September 

 of the second or third year, earthen cells are constructed by the 

 beetles, in which the transformation to the pupa occurs and the 

 adults appear the following spring. 



The rather serious injuries to grass lands last year renders it 

 very probable, in view of the above given life cycle, that the 

 beetles will be unusually numerous next summer. This suggests 

 the idea that in sections where these pests are unusually abundant 

 and injurious it might be advisable to so plan farming operations 

 as to plow under the majority of the grass lands to be devoted 

 the next two or three years to crops liable to injury by these pests, 

 the year following the abundance of the beetles ; namely, in 1907. 

 This procedure if followed by a fair amount of cultivation should 

 result in the destruction of many young grubs, as they are pre- 

 sumably less able to withstand adversity during their early exist- 

 ence than later in life. 



The subterranean habits of these pests render their control 

 somewhat difficult. There is hardly a more efifective and satis- 

 factory method of checking them in gardens, strawberry beds and 

 similar places, than by digging them out as soon as their presence 

 is indicated by the poor condition of affected plants. Repetition 

 of such trouble can be guarded against to a great extent by plant- 

 ing recently plowed grass lands infested by these grubs with crops 

 not affected by them. Neither of these methods can be emploved 

 on lawns, where occasionally considerable injury is inflicted. The 

 grubs can be killed in these latter situations by liberal applica- 

 tions of kerosene emulsion, th.e standard formula diluted with 

 about six parts of water. This trcatmont should either be fol- 

 lowed by a copious watering or be made just before a good rain. 

 The idea is that the water following the insecticide will wash it 



