THE ALFALFA WEEVIL 
( Hyper a postica) 
Larvae of the alfalfa weevil feed on 
the tips, leaves, and buds of alfalfa, 
and are particularly damaging to the 
first crop. After the first crop of alfalfa 
is cut, the larvae and adults feed heav- 
ily on the new shoots of the second 
crop. They can destroy the feed value 
of a hay crop, or prevent the profitable 
production of seed. 
This insect occurs in Maryland, Dela- 
ware, New Jersey, Pennsylvania, Vir- 
ginia, and West Virginia; in Nebraska 
and South Dakota; and in most West- 
ern States. 
DEVELOPMENT 
In most areas only one generation 
occurs in a growing season. The fe- 
male weevils lay most of their eggs in 
March, April, and May. In warm 
weather the eggs hatch in 1 to 2 weeks. 
Larvae are most abundant from mid- 
April to early June, when the first al- 
falfa crop is approaching the bud stage. 
They feed 3 to 4 weeks. When full 
grown, larvae spin cocoons on or near 
the plants, and pupate 1 to 2 weeks. 
The adults, which emerge from the 
cocoons, mate in the fall or spring. 
They overwinter in or near alfalfa 
fields. 
CONTROL . . . Eastern States 
For best control, spray alfalfa in 
mid-April when the plants are 6 to 10 
inches high. Apply heptachlor at the 
rate of 4 ounces per acre to destroy the 
small larvae. 
CAUTION. — After treating the alfalfa, wait 
7 days before cutting the crop or allowing live- 
stock to graze on it. 
CONTROL . . . Western States 
Alfalfa for Seed . — Best control is 
obtained by an early-season chemical 
treatment that kills adult weevils before 
they lay many eggs. A single appli- 
cation of insecticide is made when the 
spring growth is l/ 2 inch to 2 inches 
high. If you spray, apply heptachlor 
or dieldrin at the rate of 4 ounces per 
acre. If you dust, apply heptachlor at 
the rate of 5 ounces per acre. 
CAUTION. — After applying heptachlor at the 
4-ounce-per-acre rate, wait 7 days before cut- 
ting the treated alfalfa or allowing livestock 
to graze on it; after applying at the 5-ounce- 
Issued June 1955 
per-acre rate, wait 10 days. After applying 
dieldrin, do not allow livestock to graze on the 
treated aifalfa until after the first cutting. 
Any alfalfa weevil larvae that may 
be present on first-growth alfalfa left 
for seed will be destroyed by the in- 
secticide used to control lygus bugs. 
DDT is applied when the plants are in 
the bud stage. Generally, it is applied 
at the rate of 2 pounds per acre in a 
spray or 3 pounds per acre in a dust. 
CAUTION. — Do not feed DDT-treated alfalfa 
to dairy animals, animals being fattened for 
slaughter, or poultry. 
Alfalfa for Hay. — Early-season 
chemical treatment to kill the adults, as 
described for seed crops, is the best 
control. 
If you wait until May or June to start 
control measures, apply an insecticide 
to kill the larvae as soon as they are 
numerous on the plants. Spray or dust 
with one of the following insecticides 
at the per-acre rate indicated : Methoxy- 
chlor, 2 pounds; parathion, 4 ounces; 
aldrin, 2 ounces; lindane, 2 ounces; 
heptachlor, % ounce. 
CAUTION. — Do not allow animals to feed 
on alfalfa for 15 days after applying parathion, 
aldrin, or lindane, or for 3 days after applying 
heptachlor. 
THE SPRAY OR DUST 
To prepare a spray, buy an emulsi- 
fiable concentrate of the required in- 
secticide and mix it with water. Use 
the amount of the concentrate necessary 
to obtain the recommended dosage. If 
you use a ground sprayer, you will 
need at least 6 gallons of spray per 
acre. If the application is made with 
an airplane, as little as 2 gallons of 
spray per acre can be used. 
For dusting, use any strength of 
readymade dust sold in your area. 
Apply the amount necessary to obtain 
the recommended dosage. 
CAUTION. — Most insecticides are 
poisons. Store insecticides where chil- 
dren and animals cannot reach them. 
Follow the directions for handling. 
Heed all warnings on the container 
label. 
Parathion is particularly dangerous. 
It should be applied with power ma- 
chines only. When handling it wear a 
gas mask or respirator of a type recom- 
mended by the U. S. Department of 
Agriculture. 
U. S. GOVERNMENT PRINTING OFFICE: 1955 
For sale by the Superintendent of Documents, U. S. Government Printing Office 
Washington 25, D. C. - Price 5 cents 
