Albin W. Anderson, Research Associate,
Entomology
Richard D. Frye, Associate Professor, Entomology
Lyle Klostermeyer, Graduate Research Assistant, Entomology
The sugarbeet root maggot control program was expanded and divided into two distinct phases during the 1971 season. In addition to an enlarged field testing program, we have initiated laboratory research into the basic biology and behavior of this insect. The program will further expand, during the 1972 growing season, to include detailed study of the life cycle and ecology of this pest in nature.
The results of this year's work indicates that we have a few compounds which can be effective in controlling the sugarbeet root maggot. We believe we should have proven compounds available immediately which can be used to keep maggot damage at a minimum, regardless of weather conditions and planting time. Our basic research, however, has a long range goal: To develop a completely integrated program for controlling the sugarbeet root maggot in the Red River Valley. To achieve this, it is necessary to have a thorough knowledge of the biology, ecology and behavior of the insect.
During discussions with-entomologists from beet growing areas in the western states and Canada, one fact becomes immediately evident. While we have a general picture of the insect's biology, we lack the specific knowledge necessary to develop a successful, integrated program. Our present and future research plans are designed to give us this information. The following is a brief summary of on-going and future research. It is included in this booklet to keep you fully informed on all phases of our research program, both in the field and the laboratory.
The key to a successfully integrated control program is to determine which stage(s) of the life cycle is/are most susceptible to attack. Chemical, biological, or cultural methods then can be employed. To this end, our research depends on the availability of large numbers of maggots of all ages and on the availability of flies, the year round. We are presently developing an artificial diet which can be used to rear maggots in the laboratory. When this work is completed, a colony will be available for all phases of the research.
Detailed analyses of specific requirements of all stages of the insect in nature will be carried out. Temperature, humidity, soil moisture,light, and soil type are all important to the survival of the eggs and maggot. Further, most of these factors affect the movement of maggots through the soil. Adult requirements are mostly unknown. Environmental factors affecting adult emergence, mating, and movement must be determined; in addition to food requirements necessary for egg laying. Physical or physiological conditions which govern movement of both maggot and adults and also determine where egg laying occurs must also be known. In addition to this basic information, the availability of a laboratory colony will provide several other benefits. Some possibilities include:
A. Assessment of new chemicals in the laboratory the year around.
B. Detection of resistance to insecticide in the laboratory before it appears in the field.
C. Evaluation of the effects of various natural and artificial attractants.
D. Determination of the possibility of utilizing the irradated sterile male technique for control.
E. Assessment of synthetic or natural insect hormones as control measures to alter or break the life cycle.
F. Determination of the feasibility of cultural methods to minimize maggot infestations and damage.
The sugarbeet root maggot enters a period of "hibernation: or diapause during the fall and winter months. After this period, the insect pupates and adults are formed. When kept at warm temperatures, however, most maggots will not pupate; it appears that a cold period is necessary for further development. During July and August pupae are found in beet fields. There is some suggestion that this might be a strain which does not require a cold period for adult development or does not undergo diapause. We are presently studying the nature of the diapause to determine if strain differences occur and if this information can be used in a control program.
The laboratory work has only been in progress since September. Results are at best tentative. Additional work is in the planning stage or presently being started and will be reported on a later date.
1971 Sugarbeet Research and Extension Reports. Volume 2, pages 60 - 61.