Mimeo E-53
May 1953
Rev. June 1954(3M)
Purdue University
Agricultural Extension Service
Entomology Department

CHINCH BUG CONTROL
Chinch bugs are among the most serious pests of corn. Fortunately, they occur in destructive numbers at irregular intervals, perhaps more often following years of sub-normal rainfall. The last statewide outbreak occurred in 1935. Since then, numerous small outbreaks have occurred in western Indiana from Bloomfield north and in northeastern Indiana in an area bounded by Auburn, Marion and Richmond. These are the two areas most subject to attack.

There has been a gradual build-up since 1951, and there were moderate to severe outbreaks in 1953 resulting in a heavy carry over for 1954* Conditions to date have been favorable for the bugs and severe infestations are anticipated.

Life Cycle and Damage
Chinch bugs overwinter as adults at the base of bunchy grasses.
In early spring on sunshiny days when the temperature reaches 70°F., they fly to small grain fields where they alight and lay eggs where the grain is thin. The newly hatched bugs are very tiny and bright red in color. As they grow, they become grey and white and later black and white. They have sucking mouthparts and feed upon the sap of grain until the crop begins to ripen or is cut and then they migrate on foot to adjoining corn fields. By this time, a few of the bugs may already be mature and therefore vary in both size and color. They cluster on the corn, often until the stalks are black, causing the plants to wilt and die. The first corn attacked is always those rows next to small grain. As the plants wilt or die, the bugs move further into the field. The extent of damage depends upon the number of bugs and the size of corn. They do not feed upon anything except plants belonging to the grass family. Adult chinch bugs have been known to by-pass small grain fields and lay eggs directly on young corn. In such cases, corn fields may be generally infested with the small red bugs without any migration having ever taken place.

As the bugs mature, they fly to all parts of the corn field and lay eggs for a second generation. It is this generation which matures in the fall and flies to bunch grass to spend the winter.

Preventive Measures
The best prevention against chinch bugs is a thick, vigorous stand of small grain, and also legumes if they are planted in it. Good stands of small grain containing legumes are seldom heavily infested since the bugs are sun-loving insects and prefer thin stands for egg laying.

Dieldrin Sprays
A new insecticide known as dieldrin has given good results when applied direct to small grain fields or as a barrier strip between small grain and corn. If the grain is known to be infested, aeroplane