Document Type

Thesis - Open Access

Award Date

1970

Degree Name

Master of Science (MS)

Department

Entomology

Abstract

The western corn rootworm, Diabrotica virgifera Leconte, the northern corn rootworm, Diabrotica longicornis (Say), and the southern corn rootworm, Diabrotica undecimpunctata howardi Barber, are major pests of corn in the corn belt region. In South Dakota, the western and northern corn rootworms are the two predominant species that produce economic damage. The damage produced by this insect complex has elevated them to the position of the number one corn insect pest. In South Dakota the corn rootworm was estimated to produce 5o% of all damage that occurs to corn (Jones, 1968). The corn rootworm is an important factor in the economy of South Dakota agriculture. Kantack (1965) estimated that in 1964 this insect caused 3 million dollars damage in South Dakota. Jones (1968) estimated that the corn rootworm cost South Dakota farmers over 7 million dollars because of damage and the cost of control. Economic damage has been higher in the major corn growing states of Nebraska and Iowa. Corn rootworms damage the corn plant in several ways. The larvae feed on the roots of corn and high populations can destroy almost the entire root system. The larvae feed both externally and internally on the roots, preventing growth and damaging the roots so that they are more exposed to root rot organisms. The larvae may kill the plant altogether by their feeding, although the more common damage is reduced yields caused by the retarded growth and lodged plants which make harvesting with mechanical pickers difficult and often impossible. In addition to root damage caused by larval feeding, the adult corn rootworms damaged corn plants by feeding on the leaves and silks. Feeding on silks often resulted in poorly filled ears because of inadequate pollination. Adults may also reduce yields by feeding on kernels at the tip of the corn ear.

Library of Congress Subject Headings

Insecticides

Northern corn rootworm

South Dakota State University Theses

Format

application/pdf

Number of Pages

103

Publisher

South Dakota State University

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