REPORT OF TEE EyTOMOLOGIST AXD BOTANIST 221 



SESSIONAL PAPER No. 16 



reported. There is even yet a good deal of imcertaiuty as to the exact time required 

 for the larvffi or grubs to attain full growth. The usutil statement is tliat the eggs are 

 laid early in June. The young grubs hatch from ten to eighteen days afterwards 

 and feed on the roots of various plants until autumn. As winter approaches, they 

 burrow deeply into the ground, and, returning again to the surface on the opening of 

 spring, do much harm by eating the roots of grasses and many other kinds of plants, 

 particularly corn and potatoes, when sown on sod turned down the previous year. It 

 is claimed by Dr. S. A. Forbes, of Illinois, that a second winter, and part of the 

 following summer, are passed in the larval condition, and that the grubs do not change 

 to pupae till June and July of the third season. The perfect beetles, in such a case, 

 would issue from the pupsc in August and September of the same year, but would re- 

 main through the winter in the ground and emerge the following May and June; 

 thus three full j^ears would be required from the time the eggs were laid until the per- 

 fect beetles appeared. It is probable that some of the confusion is due to the fact 

 that several species with differing habits are spoken of under the one name of Wliite 

 Grubs. From a practical standpoint, it is a very important point to decide what the 

 exact habits are, of any species prevalent in a certain district. It is probable that, 

 3uring the first year after hatching, little harm is done by the grubs if they live for 

 the longer period. On the other hand, if the larval period covers only two seasons, 

 any one finding the nearly full-growTi grubs in spring, in land which it is desired to 

 put under crop, can by a slight change in the rotation of his crops use the land for 

 a crop which may be sown late in June or early in Jnly, and which would make small 

 root growth before the time that the grubs ceased feeding to pupate in June and July. 

 If, on the other hand, the species lives for three seasons in the land, a crop planted 

 on fields seen to be infested in spring might be seriously injured by the grubs if they 

 were in the second year of their growth and would be able to attack the crop through- 

 out the season, no matter at what time it was sown. 



The strawberry plant seems to be particularly attractive to the beetles for laying 

 their eggs, and it is probable that more complaints come in concerning depredations 

 on strawberries than upon any other crop. As general remedies, there are unfortu- 

 nately no measures which can be depended upon for the destruction of White Grubs in 

 farm crops; but, as the eggs are laid mainly in grass lands, land which has been in 

 sod for several years should not be planted to corn or potatoes the first year after 

 breaking. During the year of ploughing, the grass to a large measure feeds any 

 grubs which may be in the ground, and the next year the roots of the crop grown on 

 the land receive the full attack. It has been noticed that clover is seldom attacked by 

 White Grubs; therefore, this crop becomes of special value for growing on land be- 

 fore it is to be used for corn or potatoes. In strawberry beds it is possible to avoid 

 injury by adopting what is now known as the 'one-crop method,' which consists of 

 taking only one crop of fruit from the beds, instead of leaving these down as was 

 usually done in the past for several years. Mr. Macoun, the Horticulturist of the Cen- 

 tral Experimental Farm, tells me that this is the best method, not only for controlling 

 the Wliite Grubs, but also in getting pitying returns form the fruit crop. His ex- 

 periments show that tha best results are obtained from planting young runners in 

 spring in new beds. By autumn these have grown into strong plants, from which the 

 crop is gathered the following summer, and the beds are then ploughed down at once. 

 If young plants are required in numbers of any variety, the beds can be left for a 

 tccond year; but, to get large berries, which always pay best, the single-crop plan is 

 the most satisfactory, and all leds should as a general practice be ploughed down after 

 two crops of fruit at the most. Under this plan, the grubs have not time to complete 

 their stages and produce beetles before the beds are ploughed down. Not only is this 

 treatment an excellent way of controlling the White Grub, but two other serious 

 enemies of this crop are also prevented from increasing. These are the Black Vine 

 Weevil, Otiorhiinchus sulroiris. Fab., and the Sleepy Weevil, Otiorhynclnis ovatus, L., 

 two beetles which on many occasions have done serious injury in strawberry beds. 



