THE CLOVER ROOT BORER 45 
Adopt any agricultural practice that makes for a healthy, rapidly © 
growing root system, such as good seed from a locality known to pro- 
duce a good strain of red clover; provide a good seed bed and good 
drainage; maintain in the soil the elements required for optimum 
growth of the plant. Root borers do not thrive as well on rapidly 
growing, sappy roots as on those the growth of which has been checked. 
SUMMARY 
The clover root borer is an insect of wide distribution throughout 
the world, wherever red clover is an important crop. 
It belongs toa group of beetles which are commonly found attack- 
ing injured or weakened woody plants. 
The clover root borer feeds most commonly upon the roots of red 
clover. It is one of the principal factors limiting the life of a clover 
stand after the first crop year, and even in the first crop year has 
frequently caused large losses of hay or seed. 
The beetles migrate from old clover to new clover fields on favor- 
able days in April, May, and June, the maximum flight usually 
occurring in May. 
The eggs of this insect are laid in niches in the walls of burrows in 
clover roots, beginning late in April or in May, and hatch in 17 to 30 
days. Comparatively few eggs, probably seldom more than 20, are 
laid by each female. 
The larve develop slowly, and the first pups are not found until 
about the middle of July. The pupal period lasts from 8 to 13 days. 
As the egg-laying period of each female extends over a consider- 
able length of time, there is at-all times a great diversity in the stage 
of development of the root borers. 
New adults are not numerous before the middle of August, although 
the first new adults are found about the middle of July. 
Some larve are still immature when winter arrives, and do not 
pupate and transform into adults until April or May of the follow- 
ing year. : 
The total developmental period from egg to adult is not less than 
60 days and may be 90 days or more. The total life span of the indi- 
vidual borer may be a year or even longer. There is but one gen- 
eration a year. 
The borers pass the winter in the roots where they mature. 
The development of the clover root borer and the damage caused 
by it are influenced by climatic and soil factors, by the condition of 
the host plant, and by topography. 
The most noticeable damage to red clover by the clover root borer 
is observed in the second crop year, when the stand may be so badly 
thinned as materially to reduce the crop. Often by late summer the 
ne is practically killed out unless there has been abundant self- 
seeding. 
In regions where root borers are very abundant serious injury may 
be done to the crop in the first crop year. Young clover fields may 
be entirely killed out soon after the first hay crop, when such fields 
are situated near badly infested clover sod which has been spring 
plowed. 
Red clover is occasionally attacked even in the year of seeding. 
Alsike clover is not usually seriously injured by clover root borers. 
