Group Title: Mimeo report - University of Florida Everglades Experiment Station ; 60- 4
Title: A preliminary report on the corn stem weevil and its control
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 Material Information
Title: A preliminary report on the corn stem weevil and its control
Series Title: Everglades Station Mimeo Report
Physical Description: 2 leaves : ; 29 cm.
Language: English
Creator: Harris, Emmett D
Everglades Experiment Station
Publisher: Everglades Experiment Station
Place of Publication: Belle Glade Fla
Publication Date: 1959
Subject: Beetles -- Control -- Florida   ( lcsh )
Genre: non-fiction   ( marcgt )
Statement of Responsibility: Emmett D. Harris, Jr.
General Note: "September 15, 1959."
General Note: Caption title.
 Record Information
Bibliographic ID: UF00067549
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 65174789

Full Text

.- Everglades Station Mimeo Report 60-4 September 15, 1959

A Preliminary Report On

The Corn Stem Weevil And Its Control

By Emmett D. Harris, Jr.*

Young sweet corn plants were heavily infested last year by small white leg-

less grubs "boring" or "mining" within the stem near the ground level. Fifty

percent or more of the fields in this area were affected. In many fields nearly

100 percent of the plants were attacked. Many infested plants were stunted,

lodged in heavy winds, or wilted and died, but some showed no obvious evidence of

injury. Although it has not been completely shown in controlled experiments, the

grubs appear to cause this damage.

This insect, Hyperodes humilis (Gyll.) had not been known to damage crops

before and does not have a common name although it has been found in the United

States for many years. Because of its feeding habits "corn stem weevil" seems to

be a good name.

Eggs about 1/32 inch long are usually imbedded in the tissue of the sheath

of the lower leaves on young corn plants. They are more easily seen when the

leaf sheath is stripped from the plant and examined from the under surface. They

are creamish white when first laid but in a day or two change to dark brown.

They hatch in about three to six days.

The grubs are white with a light brown head and legless. They are about

1/32 inch long when first hatched and about 1/4 inch long when mature. They feed

about 20 to 25 days before they become pupae. The pupal stage is one in which

the insect is inactive and is changing from a larva&. to an adult.

The pupa is white and about 5/32 inch long. Pupae have not be ..

the field, but grubs reared in the laboratory pupated in corn sta ~ About four
nSE 29 1959
to nine days are spent in the pupal stage before the adult insect \jrges. A

SAssistant Entomologist, Everglads Experiment Station, Belle Glade
* Assistant Entomologist, Everglades Experiment Station, Belle Glade


The adult weevil is about 5/32 inch long and dark brown with white scales.

It has a long snout. Adults seem to be active at night and to spend the daylight

hours in the soil near the young corn plant.

Grubs also have been found attacking field corn and sorghum. Eggs have been

found on goosegrass, Elusine indica (L.) Gaertn., and nutgrass, Cyperus rotundus L.

Budworm control programs using toxaphene, DDT, heptachlor, or mixtures of

these chemicals with parathion have not controlled this pest. The best control

known at present is to apply one gallon of DDT 25 percent emulsifiable in 100

gallons of spray every four days, beginning on the day that the first young corn

seedling emerges. This schedule should be followed for about seven applications

or until the corn is about one month old. At this age the plants seem to be less

attractive to egg-laying weevils and less susceptible to grub damage. The first

three sprays can be applied at 50 gallons per acre using two overhead nozzles.

Thereafter, four nozzles should be used with the lower two aimed to hit the lower

part of the stem and the soil near the plant. At this time 100 gallons per acre

should be applied. Guthion at a dosage of one pound of actual toxicant per 100

gallons of spray has also been very effective but at present is not commercially

available for use on sweet corn. This program also should give excellent control

of budworms.

As these recommendations are the result of only one season's studies they

probably will be changed somewhat as more information is obtained about this pest

and its control.

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