‘he Literature of Arthropods Associated with Alfalfa 
Il. A BIBLIOGRAPHY OF THE SITONA SPECIES 
(Coleoptera: Curculionidae) 
I 
THE ALFALFA ECOSYSTEM is unique among field-crop 
ystems in that it represents a relatively long-lasting, well- 
stablished perennial system that exists nationally over a 
ariety of climatic, geographical, and edaphic conditions. 
ecause of the many subsystems, the interactions with 
ther specific agroecosystems or natural systems are 
qually as varied. Alfalfa supports a wide variety of in- 
cts. These include destructive insects, pollinating insects, 
yecies that inhabit the fields because of the lush habitat 
ut have little effect on the crop, and many associated 
redators and parasites. Because of the perennial growth 
abits of alfalfa, many pest and beneficial insect species 
f other crops overwinter or build up in alfalfa before 
ligrating to neighboring crops systems. 
Considerable laboratory and field data dealing with 
nemical, biological, and cultural methods of control of 
falfa insects are available. These data need to be closely 
iterpreted with respect to their implications for inte- 
rated control and then applied in integrated pest man- 
sement programs in the field. The breadth and depth 
“research on alfalfa insect control and alfalfa produc- 
on in general have been sufficiently productive to imple- 
ent some programs now. 
To facilitate use of existing literature in developing 
st management systems, bibliographies of the key pest 
ecies on alfalfa are being prepared for use by research- 
s. This bibliography on Sitona species (Coleoptera: 
urculionidae) is the second in a series concerning 
falfa insects of economic importance. This and subse- 
lent bibliographies of arthropods associated with alfalfa 
e part of an information storage and retrieval system 
‘ing compiled as one objective of the US/IBP project 
titled “The Principles, Strategies, and Tactics of Pest 
lanagement Regulation and Control in the Alfalfa Eco- 
stem.” This information system utilizes existing facilities 
id methodology employed by the University of Illinois 
yybean Insect Research and Information Center. SIRIC 
is developed a set of computer programs for the IBM/ 
1) at the University of Illinois which makes possible 
€ retrieval of literature citations associated with a sub- 
et or combination of subjects. The bibliographies of 
e key alfalfa pests, starting with Therioaphits maculata 
ve been stored on magnetic. tape and are retrievable 
ing the SIRIC system. 
The genus Sitona includes a large number of species, 
y of which are known to be injurious to leguminous 
ps (Wildermuth 1910).* In general, the larvae are 
te reference number 570 in the following bibliography. 
W. P. Morrison, B. C. Pass, 
M. P. Nichols, and E. J. Armbrust 
root feeders, whereas adults attack the foliage. Arnett 
(1962)? reports 17 species of Sitona as occurring in the 
United States. Several species have been introduced into 
North America from Europe and are now pests on both 
continents. The crops most commonly attacked are clover, 
alfalfa, peas, beans, and vetch. The pest species include: 
S. lineata (pea leaf weevil), S. cylindricollis (sweetclover 
weevil), S. hispidula (clover root curculio), S. scissifrons 
(lesser alfalfa weevil), and S. flavescens (yellow clover 
curculio). 
The clover root curculios eat small crescent-shaped 
notches on the edges of alfalfa and clover leaves. The 
larvae feed on the roots, pitting and scarring the surface. 
They may also burrow into the root, but they do not 
hollow out the center as the clover root borer does. If 
feeding is severe, the root may be almost girdled and the 
plant may die during warm, dry weather. The curculios 
feed primarily at night and are seldom found on the 
plants during the day. 
Clover root curculios winter mainly as larvae, but a 
few may spend the winter as adults or eggs. Wintering 
larvae feed on the roots in early spring and emerge in 
the spring. The adults feed for a time in the late spring, 
become inactive during the summer, and feed again in 
the fall. They lay eggs throughout the fall, often as late 
as mid-November. Eggs laid late in the season overwinter, 
but those laid earlier hatch and the larvae overwinter. 
If all eggs are not deposited in the fall, the adult over- 
winters and completes egg-laying in the spring. The 
sweetclover weevil hibernates in ground debris in and 
around sweet clover fields. With the first warm weather, 
it begins to feed on the plants, notching the leaves no- 
ticeably. The females lay eggs in the spring. The young 
grub-like larvae feed in clover soils in late May, June, 
and July. They pupate in late June and July, emerging 
as adults in July and August. The adults feed moderately 
in the fall prior to winter hibernation. 
The weevils feed on the larvae of sweet clover plants, 
retarding the spring growth of established stands. Only 
in rare instances are established stands killed, but weevils 
will often consume an entire new seeding or seriously 
? See reference number 50 in the following bibliography. 
This paper, in the Biological Notes series, is published with special project 
funds. Dr. W. P. Morrison is a Post Doctoral Fellow and Dr. B. C. Pass 
a Professor of Entomology at the University of Kentucky. M. P. Nichols is 
a Research Associate, International Programs and Studies, University of Illi- 
nois. Dr. E. J. Armbrust is an Associate Entomologist at the Illinois Natural 
History Survey and Associate Professor of Agricultural Entomology, Illinois 
Agricultural Experiment Station. 
