Soil Degradation Comparisons of Corn Rootworm Insecticides in the Field and Laboratory

South Dakota State University Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange Electronic Theses and Dissertations 1987 Soil Degradation Comparisons of Corn Rootworm Insecticides in the Field and Laboratory Michael J. Haas Follow this and additional works at: https://openprairie.sdstate.edu/etd Recommended Citation Haas, Michael J., "Soil Degradation Comparisons of Corn Rootworm Insecticides in the Field and Laboratory" (1987). Electronic Theses and Dissertations. 4447. https://openprairie.sdstate.edu/etd/4447 This Thesis - Open Access is brought to you for free and open access by Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange. It has been accepted for inclusion in Electronic Theses and Dissertations by an authorized administrator of Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange. For more information, please contact [email protected]. SOIL DEGRADATION COMPARISONS OF CORN ROOTWORM INSECTICIDES IN THE FIELD AND LABORATORY BY MICHAEL J . HAAS A thesis submitted in partial fulfillment of the requirements for the degree Master of Science Major in Entomo logy South Dakota State Univers ity 1987 SOIL DEGRADATION COMPARISONS OF INSECTICIDES IN THE FIELD AND LA BORATORY This thesis is approved as a creditable and independent investigation by a cand idate for the degree , Master of Science , and is acceptable for meeting the thesis requirements for this degree . Acceptance of this thesis does not imply that the conclusions reached by the candidate are necessarily the conclusions of the major department . David D. Walgenbach Thesis Adviser j MaJrlce L. Horton Date �ead , Dept . of Plant Science ACKNOWLEDGEMENTS I would like to extend my sincere gratitude to Dr . David Walgenbach for his guidance during this pro ject . Thanks also goes to Dr . Duane Matthees for his assistance with the laboratory analysis . TABLE OF CONTENTS INTRODUCTION •...•....•.•••..••••· . • • . • . 1 LITERATURE REVIEW ......• 5 Rootwor m Control History .. 5 Pesticide Degradation. 9 Carbo fur an ..........•..•...•.........•..... 19 Fonofos ...... • • • • • • • • • I • • • • • • • • • • • • • • • • • • • • 24 Chlorpyrifos . 27 Terbufos . 2 9 MATERIALS AND METHODS . • . • . 3 2 RESULTS AND DISCUSS ION ....................•........ 40 CONCLUSIONS .. 73 LITERATURE CITED .........•......................... 75 APPENDICES . 86 i LIST OF FIGURES Figure 1 Carbofuran residue level·s for three successive applications to Brookings soil in the laboratory .•....•...........•.....•. 44 2 Carbofuran residue levels for three successive applications to Garretson soil in the laboratory . • . 4 5 3 Carbofuran residue levels for three successive applicat ions to Hurley soil in the laboratory . 4 6 4 Fonofos residue levels for three successive applications to Brookings soil in the laboratory . 49 5 Fonofos residue levels for three successive applications to Garretson soil in the laboratory ... ... .... .......... ..... 50 6 Fonofos residue levels for three successive applictions to Hurley soil in the laboratory .......................... 51 7 Chlorpyrifos res idue levels for three successive applications to Brookings soil in the laboratory ...... ........ .. .... .... 54 8 Chlorpyrifos residue levels for three successive applications to Garretson soil in the labora tory . 55 9 Chlorpyrifos residue levels for three successive applications to Hurley soil in the laboratory . ... ....... .. ...... ... 56 10 Terbufos residue levels for three successive applications to Brookings soil in the laboratory ·········· � ··············· 59 11 Terbufos residue levels for three successive applicat ions to Garretson soil in the laboratory . .. .... ... .... ........ 60 ii LIST OF FIGURES (continued) · 12 Terbufos residue levels 'for three successive applications to Hurley soil in the laboratory •............... .......... 61 iii LIST OF TABLES Table 1 Field locations , soil analysis , and insecticide use histories .................. 33 2 Soil residues of rootworm insecticides at Centerville in 1985 ..••..� . • . 65 3 Soil residues of rootworrn insecticides at Garretson in 1985 •.................... •v• ••• 65 4 Soil residues of rootworrn. insecticides at Hur 1 ey in 19 8 5 . 6 6 5 Soil residues of rootworrn insecticides at � ..........· Brookings in 1986 .......•........ 70 6 Soil residues of rootworrn insecticides at Garretson in 1986 .......................•... 70 7 Soil residues of rootworrn insecticides at Hurley in 1986 ............................. 71 iv INTRODUCTION Pesticide use for crop protection is an impor tant part of most field crop production programs . Herbicides and insecticides are the two most frequently used pesticide types in the United States (USDA 1980) . These·may be applied foliarly or directly to the soil . In order to provide satisfactory control these ' pest icides must be present when the pest is present and at a sufficient level to achieve the desired control. This may mean that residues are expected to persist for several weeks or for several months . The period of time during wh ich a pesticide will remain biologically active in the soil is determined by biotic and abiotic factors . Temperature , moisture , soil type , cropping history , pesticide use history , and the microbiological composition of the soil all influence the persistence of pesticides . Degradation by soil microorganisms is the primary factor affecting the persistence of most pesticides (Laveglia and Dahm 1977). The ability of a pesticide to provide the desired level of control may be lost or dimini shed after repeated soil applications with the same chemical. The microbial population of the soil may develop the capaci ty to rapidly degrade a-compound to which it has 2 been repeatedly exposed . This loss of pers istence due to rapid degradation of a compound by an adapted microbial population is known as enhanced microbial degradation, or enhanced biodegradation (Kaufman and Edwards 1983) . In 1949 Audus showed that failure of 2,4- D to control weeds in soil receiving.prior applications was due to a microbiological factor which rapidly degraded the compound . The loss of weed control in New Zealand plots which had received at least three successive applications of EPTC was reported by Rahman et al . (1979) . Further studies showed that enhanced microbial degradation was responsible . Bufencarb , a carbamate corn rootworm (Diabrotica s� .) insecticide did not give satisfactory control in South Dakota field trials in 1971 and 1972 (Walgenbach 1974) . Poor performance was also reported in Illinois and Nebraska field trials (Kuhlman 1974) . By 1974 the Extension Serv ice in Iowa no longer suggested- it be used for rootworm control . The organophosphate insecticide isofenphos failed to control rootworms in Univer·sity of Wisconsin field trials in 1982 . It was removed from the market the following year due to widespread complaints about its performance for rootworm control . Coats et al . 3 . (1985) subsequently showed enhanced biodegradation in the field and laboratory . Felsot et al . (1981) reported poor control of corn rootworm in several fields in Illinois where carbofuran , a systemic carbamate soil insecticide , had been applied annually for three or more years . Lack of persistence was determined to be· the probl em . Steril ization of soils via heat , gamma irradiation, or antibi otics destroyed the soils ability to rapidly degrade carbofuran . This suggested the presence of a biological mechanism responsible for the rap id disappearance of the compound . Other studies have also shown that carbo furan may be rap idly lost in soils receiving prior applica tions (Felsot et al . 1982 , Gorder et al . 1982) . Ahmad et al . (1979) and Gorder et al . (1980) did not see a connection between prior use of carbofuran and decreased pers istence in laboratory treatment of severa l soils. In 1984 reports of poor rootworm control came from several locations in eastern South Dakota . An investigation was initiated to follow insecticide persistence patterns in these soils both in the field and in the laboratory . Objectives of the study were to determine if insecticide persistence patterns at these locations indicated that a rap id loss of the insecticide 4 was responsible for lack of control , and to dete rmine if rapid degradation ·could be induced in the laboratory through successive soil treatments with the same chem i cal . 5 LITERATURE REVIEW ROOTWORM CONTROL HISTORY The use of control measures as protection against larval corn rootworm (Diabrotica sp . ) . feeding damage dates to at least 19'1.2 when Gillette recommended . that crop rotation be pract iced (Gillette 1912 , Hill et al . 1948) . Since that time crop production has become increasingly sophisticated yet rotation is still one of the best control practices that exist . However, with the advent of affordable chemical control the ability to grow continuous corn in a large- scale monoculture system was realized. The United States Department of Agriculture estimated in 1980 that 500 million kilograms of pesticides are applied annually in this country for agricultural purposes . This included herbicides , insecticides , nematicides , molluscicides , and fumigants. A large percentage of �hese pesticides are applied directly to the soil. Of those pesticides applied above-ground only ca. 1% actually hit the intended target pest (Graham-Bryce 1975) , a portion either drifting to the ground , ·or entering

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