|
The Boll Weevil In Mississippi:
Gone, But Not Forgotten
Printable PDF Version (13 pages)
|

Figure 1. Boll
weevil pheromone traps are memorial monuments to one of Mississippi's
most important insect pests. Without the pheromone trap, it would
have been impossible to eradicate the boll weevil. Pheromone traps
are also the most important tool for detecting boll weevel reinfestations.
Consequently, Mississippi cotton growers should take care to avoid
damaging traps that are being run in their fields. |

Figure
2. this graph records historical yield losses caused by boll weevils
in Mississippi. Note that losses exceeded 5 percent in some years.
Yield losses were lowest following unusually cold winters (1983-84
and 1989-90) because such winters result in high mortality of
overwintering boll weevils.
|

Figure
3. The elongated snout of the boll weevil is the key characteristic
that many people use to identify this pest. However this elongated
snout is a charracteristic that the boll weevil shares with hundreds
of other members of the weevil family.
|
|
A. B.

Figure
4. Both the pecan weevil (A) and the billbug (B) have snouts, but
they are not boll weevils. |

Figure
5. Characteristics that can be used to identify boll weevils include
the faint light strip through the center of the thorax (A) and
the two spurs that are present on the large club-shaped segment
of each front leg (B). Note that the inside spur is about twice
as long as the outer spur.
|
|
A. B.

Figure
6. Feeding punctures (A) which are made by both male and female
boll weevils, are easily confused with feeding damage caused by
small caterpillar larvae (B). |
| 
Figure 7. The
raised, pimple-like oviposition puncture caused by female boll weevils
is a sure sign of boll weevil infestation. |

Figure 8. Flared
squares can be caused by many different insects, including boll
weevils. |
| 
Figure
9. Detection of a boll weevil larva (A) or pupa (B) is a sign of
boll weevil infestation.
|
| 
Figure 10. This
graph shows the number of female boll weevils that could potentially
result after five generations if all progeny from a single female
boll weevil survived and reproduced (assuming each female has 150
offspring, half of which are females). While such high survival
rates would never occur naturally, this example emphasizes the high
reproductive potential of the boll weevil and the need for early
detection of reinfestations. |

Figure 11. A
boll weevil can complete all four stages of its life cycle in about
3 weeks. There are about five generations per year. |
Back
to the publication.
By Blake Layton,
Ph.D., Extension Entomology Specialist
Mississippi
State University does not discriminate on the basis of race, color,
religion, national origin, sex, age, disability, or veteran status.
Publication 2294
Extension Service of Mississippi State University, cooperating with U.S.
Department of Agriculture. Published in furtherance of Acts of Congress,
May 8 and June 30, 1914. Joe H. McGilberry, Interim Director
(2M-2-02)
|