1:6 BULLETIN 1426, U. S. DEPARTMENT OF AGRICULTURE 
f 
Injury to peas and vetch may occur when these crops are grown 
near badly infested old clover fields. 
Clover root borers have been found on alfalfa plants/ but there is 
probably little danger that alfalfa will be generally or seriously 
attacked. 
The clover root borer has but few natural enemies; an entomoge- 
nous fungus, eight species of birds, and the larvae of predacious 
beetles have been recorded as preying on the species. 
Clover root borers can be killed in large numbers by plowing up 
badly infested clover roots and harrowing them to the surface of the 
soil, at any time between the middle of June and the beginning of 
August. 
Many root borers may be killed by plowing and harrowing clover 
soon after the seed crop or second cutting of hay. This practice also 
induces an abnormal activity of the surviving root borers in the fall 
and early spring, which is detrimental to their successful propagation. 
Late fall and winter plowing and the practice of green manuring 
have little restraining effect on the clover root borers. 
Spring plowing of heavily infested clover sod has no remedial value 
and may cause severe damage to new clover in the vicinity. 
Serious injury to clover in the first crop year may be avoided by 
cooperation of the community in farm practices which will reduce the 
numbers of the root borers to a point where they can not aggressively 
attack the clover. A one-crop system of clover culture, together 
with a general practice of early fall plowing of clover sod, and, in 
exceptionally severe cases, summer plowing and harrowing, should 
free a community from appreciable damage by the clover root borer 
in the first crop year. 
LITERATURE CITED 
(1) Bach, M. 
1849. BOSTRICHTJS KALTENBACHII, EINE NETTE ART. Stettin. Ent. Ztg. 
10: 199-200. 
(2) Bedel, L. 
1876. [hylastes trifolii.] Bui. Soc. Ent. France 1876: clviii-clix. 
(3) 
1888. FAUNE DES COLEOPTERES DU BASSIN DE LA SEINE. t. 6. Paris. 
(4) Blackman, M. W. 
1915. OBSERVATIONS ON THE LIFE HISTORY AND HABITS OF PITYOGENES 
hopkinsi swaine. N. Y. State Col. Forestry, Syracuse Univ., 
Tech. Pub. 2: 11-66, illus. 
(5) Cecconi, G. 
1899. danni dell' "hylastes trifolii" mull, verificatisi in piante 
legnose vallombrosa. Riv. Patol. Veg. 8: 160-165, illus. 
(6) Chapman T. A. 
1869. NOTE ON THE HABITS OF PHLCeOPHTHORUS rhododactylus and 
hylastes obscurus. Ent. Mo. Mag. 6: 6-8. 
(7) Chapuis, F. 
1873. synopsis des scolytides. Mem. Soc. Roy. Sci. Liege 3: 213-269. 
(8) CORDLEY, A. B. 
1896. the clover-root borer in oregon. Webfoot Planter, March 24. 
[Not seen. Reference in U. S. Dept. Agr., Div. Ent., Bibliog. 
Amer. Econ. Ent., Part 6, p. 33. 1898.] 
(9) Davis, G. C. 
1894. insects of the clover field, part i. insects destructive to 
clover. Mich. Agr. Expt. Sta. Bui. 116: 41-47, illus. 
(10) ElCHHOFF, W. J. 
1881. die europaischen borkenkafer. 315 p., illus. Berlin. 
