CHAPTER XX 

 INSECTS INJURIOUS TO THE STRAWBERRY * 



The Strawberry Root-louse f 



IF bare spots are found in the strawberry bed and the neigh- 

 boring plants are unhealthy, the presence of the root-louse may 

 be suspected, especially if ants are abundant around the plants. 

 If present, the small dark green or blackish aphids will be found 

 clustered on the roots and stems, caus- 

 ing the plants to wither and die. The 

 individual aphid is only about one- 

 twentieth inch long, and deep bluish or 

 greenish-black when mature, the young- 

 er stages being lighter, and somewhat 

 pear-shaped as shown in Fig. 324. 



Injury by this pest was first noted in 

 southern Illinois in 1884 and a few years 

 later it became troublesome in Ohio. In 

 the late '90s it ruined many beds on the FIG. 324. The strawberry 



Maryland-Delaware peninsula and be- ot-louse ( Aphi * - forbesi 

 ...... JL o.- Weed) ; wingless viviparous 



came established in New Jersey. Since female of late summer- 

 then it has become distributed on plants g reatlv enlar ged- 

 throughout most of the states east of the Rockies, injury having 

 been noted in New Hampshire, Michigan, Minnesota, Kansas, 

 Texas, and Kentucky. Injury is most severe on light, sandy 

 soils and the pest rarely becomes very troublesome on heavier 

 soils. Injury is also more or less periodic, the aphids almost 

 disappearing after doing serious injury for two or three years. 

 Fortunately the strawberry is the only food plant and the root- 

 lice found on other crops are entirely different species. 



* See L. Bruner, Report Nebraska Horticultural Society, pp. 49-100; 

 J. B. Smith, Bulletin 225, N. J. Agr. Exp. Sta.; A. L. Quaintance, Bulletin 

 42, Fla. Agr. Exp. Sta.; S. A. Forbes, 13th Report State Ent. of 111., pp. 

 60-180. 



t Aphis forbesi Weed. Family Aphididoe, See Sanderson, Bulletin 49, 

 12th, 13th and 14th Reports, Del. Agr. Exp. Sta. 



389 



