STRAWBERRY PESTS 



1947 



and abdomen have a transverse row of 

 reddish-brown hairs. 



Seasonal History 



The strawberry root weevil is single 

 brooded. The adult beetles may remain 

 alive and active for more than a year. 

 There are then for a short period of 

 time two generations of beetles present. 

 This complicates matters somewhat and 

 affords a reasonable chance for error in 

 checking up the life history. These 

 beetles are busily engaged in feeding on 

 the foliage of the strawberry and other 

 host, ragging and stripping it. The in- 

 sects pass the winter in both the adult 

 and grub stage. The beetles hibernate in 

 all conceivable sorts of places. Many of 

 them become restless in early September 

 and begin seeking a place for hiberna- 

 tion. Very often in this search they en- 

 ter dwellings and prove a source of no 

 little worry to the housewife by crawl- 

 ing over and under everything and drop- 

 ping from the walls and ceiling into 

 dishes and vessels. Many of them remain 

 in the field, hibernating in the soil up 

 close about the crown of their host, or 

 crowded down into the sheaths about the 

 central whorl of the crown. 



They have been found in bundles of 

 shingles, in bundles of bedding and in 

 crates of nursery stock and other trans- 

 portable material. This may account in a 

 large measure for their spread to new 

 localities. The grubs pass the winter in 

 the soil about the roots of their hosts. 

 A portion of them are mature in late 

 fall, and even form in the soil what will 

 constitute the pupa cell. The major- 

 ity of the grubs pass the winter as near- 

 ly mature larvae, feeding to a limited 

 extent on their host. A very few grubs 

 occur during the winter as only half- 

 grown larvae, and these naturally pro- 

 long the period of pupation and emerg- 

 ence of the adult weevils the following 

 spring. 



The first pupae occur in early May. 

 During late May and June the majority of 

 the new generation of beetles emerge. 

 Even earlier than this the overwintering 

 brood of beetles assume a traveling habit 

 and crawl for a considerable distance. 



The new generation of beetles also travel, 

 and during May the housewife is again 

 worried by the presence of this beetle in 

 the house. About two weeks after the 

 new generation of beetles commence to 

 emerge the first eggs are found. The ma- 

 jority of these eggs are deposited prom- 

 iscuously through the soil from one-half 

 to three inches below the surface and ex- 

 tending from close about the crown out 

 in a radius as great as that covered by 

 the foliage of the plant. Later in the 

 season as the soil dries out, eggs are de- 

 posited about the central growing whorl 

 of the crown, usually well down among 

 the sheaths. They are also found in 

 cracks and crevices frequented by the 

 beetles and in tunnels that sometimes oc- 

 cur about the base of the plants. These 

 tunnels are mentioned by Cooley* as 

 formed by the beetles, but it is my belief 

 that they are formed by earth worms and 

 are simply appropriated by the beetles. 

 The largest number of eggs deposited by 

 a female in confinement was 43. The 

 beetles themselves feed at night and dur- 

 ing the day crowd down in dark sheltered 

 places. They will often be found in num- 

 bers under a clod, in a crevice or crack in 

 the soil, in the tunnels mentioned above, 

 or crowded down about the crown of the 

 plant itself. 



The eggs begin hatching in about nine 

 days, and unlike the egg of many insects, 

 will hatch even in dry soil. By far the 

 majority of the eggs are deposited during 

 June. The young grubs are fairly hardy 

 and active. They can live in dry soil 

 for 36 hours without food, and can travel 

 over loose dry soil at the rate of eight 

 inches In 16 hours. 



dl 



Fig. 3. Adult Larva and Pupa of Large Weevil 

 found at Milton, Oregon. 



♦Cooley, R. A., Montana Experiment Station 

 Bulletin 55. 



