Seventeen light traps were installed in 6 counties in southwest Minnesota in 1962 and 1963 and the nightly catches of moths of the European corn borer were recorded. The results show that moth catch was higher during nights with south winds and the nights immediately following such nights. This relation occurred over a large area and during the entire flight period. Moth popu1\u27otion in southern Minnesota was increased when south winds prevailed during the Right period. The trapping and recording were carried out by 15 FFA members, l 4-H member, and l adult farmer. The project demonstrates that these young people represent a valuable pool of human resources for use in salving certain scientific problems

Chiang, H. C.

Ewert, M. A.

Sisson, Vern

English

University of Minnesota, Morris (UMM): Digital Well

Journal of the Minnesota Academy of Science Volume 33 Number 1 Article 6 1965 Northerly Movement of Corn Borer Moths in Southern Minnesota H. C. Chiang University of Minnesota, St. Paul Vern Sisson University of Minnesota, St. Paul M. A. Ewert University of Minnesota, St. Paul Follow this and additional works at: https://digitalcommons.morris.umn.edu/jmas  Part of the Entomology Commons Recommended Citation Chiang, H. C., Sisson, V., & Ewert, M. A. (1965). Northerly Movement of Corn Borer Moths in Southern Minnesota. Journal of the Minnesota Academy of Science, Vol. 33 No.1, 17-19. Retrieved from https://digitalcommons.morris.umn.edu/jmas/vol33/iss1/6 This Article is brought to you for free and open access by the Journals at University of Minnesota Morris Digital Well. It has been accepted for inclusion in Journal of the Minnesota Academy of Science by an authorized editor of University of Minnesota Morris Digital Well. For more information, please contact skulann@morris.umn.edu. Northerly Movement of Corn Borer Moths in Southern Minnesota H. C. CHIANG". VERN SlSSON ", and M.A. EWERT 1 University of Mi1111esota, St. Paul. Mi11nesotu ABSTRACT-Seventeen light traps were installed in 6 counties in southwest Minnesota in 1962 and 1963 and the nightly catches of moths of the European corn borer were recorded. The results show that moth catch was higher during nights with south winds and the nights immediately fol'• lowing such nights. This relation occurred over a large area and during the entire flight period. Moth popu1'otion in southern Minnesota was increased when south winds prevailed during the Right period. The trapping and recording were carried out by 15 FFA members, l 4-H member, ond l adult farmer. The project demonstrates that these young people represent a valuable pool of human resources for use in salving certain scientific problems. The urope· m corn borer. Ostrinia 1111bila!is (Hbn . ), is one uf rhe most important insect pests of corn in Min-nesota. It overwinters as a mature larva that pupates in May. Adul t moths emerge and oviposit in June. Larvae feed on kaves, sheaths. tassel, and finally in the stalks of corn. Snm,' of the larvae pupate and change to adults in late July. August, and early September. The eggs from th se aduit s result in a second brood of infestation. The leH:- i of the second-brood infestation in a given locality is dependent upon the amount of summer pupa-tion and the number of moths that may come in from other localiti es . Stirrett ( 1938), in his thorough study of the factors affecting corn-borer moth 11ight, did not mention the im-portance of wind direction and indicated that winds of vcloci ti s f 5 to 25 mph had little effect on r1ight. Schurr and H oldaway ( 1965) observed large-scale dispersal fl ights of o m borer moth · in southern Minnesota during two co r1-ecutivc summers. They considered that these tl ights orig inated in areas f fowa but did not study the po siblc effect of winds. The present study is conducted ( I ) to verify the flight trom th~ ~ uth, ( 2) to determine if such flights take place throughou t the period of summer-brood moth ac-tivity. anJ ( 3) to determine if such 11ights are assoc iated with certain wind and temperature conditions. The general procedure was to set up a series of light traps along a 150-mile eas t-west transect located in the southernmost tier of counties in Minnesota. The trap.-were Jes · than 20 miles from the lowa boarder and were in positions to intercept moths Hying northward from Iowa. Through the assistance of Vocational Agricultural teacher~ in six counties in southwest Minnesota ( R ck, ' Pa per No. 56f, I Scientific Journal Series, Minnesota Agricul-tural Experiment S1ation. St. Paul. Minnesota 551 ()I. 'B.S. T :, ing Hua U nivers ity . China; M.S. and Ph.D .. Univer-sity of Minnesota. AI pre.se n! . Professor, Department of Erllo• molugy. F i,h eries . and Wildlil'c. Universi1v of rvlinnesota. Re-search interests. insecl ecology. " B.S. u,tavus Adolphus College. St. Peter, Minnesola. Gradualc , rudent and graduate assistant , Departmenl of Ento-mology. Fishe ries, and Wildlife. University of Minnesota. Present address: D a !ant and Sons. Hamilton, Illinois. 'B.S. Stanford University. S1anford, California. M.S. Univer-sity of Minneso1a. Graduate assis tant , Departmenl of En1omology. Fisheries. and Wildlife. University of Minnesota . Jo urnal of . Volume Thirtv-three , No. 1, 1965 Nobles , Jackson, Martin. Faribault, and Freebo ·n). 17 cooperators ( 15 FFA members, one 4-H member, and one adult farmer) were recruited (not including the one whose records were not used) . ach helped by placing one trap on hi s farm and by checking the moth catch daily during the second-brood moth flight. The distribu-tion of the traps is shown in Figure I. Thirteen of the 17 cooperators continued the project in 1963, and one recruited a neighbor to substitute in J 963. MIN, ESOTA IOWA 1c. I. The distribution or the 17 li,!ht traps in the Ii cou nties in sou thwest M.innesota. Procedures F rom August J to August 31 , 1962, and from July 21 to September 9, 1963, the numbers or male and female moths caught in each trap each night were recorded. Be-fo re the season began each cooperator was visited and furnished with a reference collection containing male and female com-borer moths and other moths that could be mistaken for corn borer-moths. Assistance was given to each cooperator in selecting the site on his farm for in-stalling: the trap. Detailed written instructions and record sheets were furnished. During the season, guidance when needed was given to the cooperators by their teachers. The cooperators and their teachers were visited again at the end of the season. Their performance and reliability by their identifications were evaluated by both their teachers and us. The records of one individual in the initial group were not used because his identification was of doubtful accuracy. The correlation between the number of moths caught and weather conditions was analyzed. Each cooperator recon.led the daily maximum and minimum temperatures. Neither the cooperators nor the nearest official weather stations kept wind records, however. Therefore, the wind records kept by five stations located around the trapping area were analyzed. It was found that the major charac-17 teristics of winds were very similar in the five localities (Minneapolis, Minnesota; Rochester, Minnesota; Des Moines, Iowa; Sioux City, Iowa; and Sioux Falls, South Dakota), suggesting that the wind pattern over the en-tire area, including the transect of traps, was about the same. Since we were interested in the effect of the winds from the south, the records of Des Moines, Iowa were used. The effectiveness of the wind in the northward move-ment of moths depends on ( 1) the northward component of the wind and ( 2) the velocity of the wind. The north-ward component of winds of different directions is rep-resented by the sine function of the angle between the wind direction and the east-west axis, as shown in Ta-ble 1. Table I. Sine Functions of Winds of Different Directions degree from the Direction of wind east•west axis Sint function s 90 1.0 SSE. SSW 67.5 0.9 SE.SW 45 0.7 ESE. WSW 22.5 0.4 E.W 0 0 ENE. WNW 22.5 -0.4 NE.NW 45 -0.7 NNE. NNW 67.5 -0.9 N 90 -1.0 The effectiveness of the wind was computed by multi-plying the sine function of the wind direction and the wind velocity. The vector was computed for each hour from 7: 00 p.m. to 6: 00 a.m. and the hourly values were summed to give the overall south-wind vector for the night. If the moth flight was associated with south winds, it was hypothesized that high catches would occur during nights with a high positive vector and low catches with a negative vector. Results At the initiation of the study, it was hypothesized that with traps spanning over 150 miles along an east-west transect, catch records of individual traps might show some differences due to local typography and to their po-sitions relative to the source of moths. After studying the records it was soon realized that if such differences were present, the samples were not large enough to analyze the effects of topography and proximity to population concentrations. Therefore, the traps were simply consid-ered as replicates. This was justified also because the wind pattern showed. no consistent differences along the entire transect. The average minimum temperatures, the wind vectors and the average number of moths caught per trap were plotted. Those for 1962 are in Figure 2, and for 1963 in Figure 3. Discussion The results show that high catches occurred during nights with a strong south wind, or during nights follow-ing such nights, and that this relation held during the 18 t 70 w >- 60 z i c:. < 0:: .... ! so ~20 a. >-::c <:, :, < u "' ::: b10 ::i; ... 0 0 z 50 0: "' Q. .... :,: <!) 40 ;i 20 u V, :r .... 0 :E u. 0 o 10 z ,j It :: .. !l f'J \ i l r ~ I\]\ l\t II 21 AUGUST •50 .40 .•., ::.; .. r-··.,i V ,30 , 20 ,10 0 - 10 -20 FIG. 2. The daily minimum temperature. wind vector and moth catch, August I-August ~ ' · 1962. i\ 2 '1 11 21 JULY AUGUST SEPT. 0: 0 .... u "' > •SO u w 0> -10 -20 - 50 FtG. 3. The daily minimum temperature, wind vector and moth catch, July 21 to September 9, 1963. The Minnesota Academy of Science month of August, in 1962, and for the entire flight period in 1963. It should be noted that because of the local me-teorological patterns, nights with predominantly south winds also had higher minimum temperatures that also favored moth activity. The wind conditions in August, 1963, had more nights with negative wind vectors, indicating that fewer nights were favorable to moth movement from Iowa into Min-nesota. The general level of moth catch was much lower in 1963 than in 1962. It is conceivable that the south wind not only moves moths from Iowa into Minnesota, but also will induce a continuous northward displacement. If this were true, then, when there were more warm nights and more south winds during moth flight in a given year, borer infesta-tion would be found further north in Minnesota. This situation in fact occurred in 1949. In that year, the sea-sonal temperature was the highest in a 10-year period ( Chiang and Hodson, 19 59a), and the infestation ex-tended farthest north ( Chiang, 1961). The second-brood adult population in a given area may be increased if the number of moths carried into the area exceeds that carried out of the area, and it may be reduced if the reverse is true. Since the borer popula-tions south of Minnesota are likely to be higher, the dis-placement induced by south winds is likely to result in increases in moth populations in southern Minnesota. This was shown by the population records kept in Wa-seca, Minnesota, in 1955. In that year, the seasonal tem-perature was high, particularly in August (Chiang and Hodson, 1959a, Chiang et al, 1961), the per cent in-crease of borer population from summer to fall was also the highest both in an experimental plot ( Chiang and Hodson, 1959b), and in Waseca County as a whole ( Chiang et al, 196 I ) . In conclusion, the study shows that moth catch was higher during the nights with south winds and the nights immediately following such nights . This relation occurred over a large area and during the entire flight period. Moth population in southern Minnesota was increased when south winds prevailed during the flight period. A Special Note Regarding the Cooperators The names of the cooperators, their teachers, schools and home counties are listed below. Their efforts are gratefully acknowledged. Working with these young people was an interesting experience for the authors. In six cases, two brothers served as a team and operated one trap. In some others, the entire family showed intense interest. Many of the cooperators received club credits in undertaking this project, and some received local press publicity. Thus, this activity, besides providing us with useful data, also aroused local interest in insect problems and highlighted the programs of FFA and 4-H clubs. Several of the co-operators continued to help us in another project in 1964. Individually, the cooperators gained experience in ob-Journal of, Volume Thirty-three, No. 1, 1965 FFA Member Cooperators Vocational Agricullural Teacher School Baker, Warren & Erickson, Wendell Hills H.S. Gerhart Bremer, Howard & Bellin, Floyd ''' Martin Ceylon H.S. County Rock l\fartin Boettcher, John Johnson, Ramsey Blue Earth H.S. Faribault Carson, Howard & Stassen, Kenneth Sioux Valley H.S. Jackson Douglas Clymer, Larry Evans, Paul Friedel. Dennis Hansen, Karen*" Schwieger, Delbert Jackson H .S. Jackson Johnson, Ramsey Blue Earth H.S. Faribault Nelson, John Alden H.S. Freeborn Luverne H.S. Rock Harens , Dave & Larson, Walter Worthington H.S. Nobles Don Murray, Daryl Johnson, Ramsey Blue Earth H.S. Faribault Ricard, Darwin, & Bellin. Floyd Granada H.S. Martin Leland Ruskell , Ken Schweiger, Delbert Jackson H.S. Jackson Saxon, Dale Swanson, LeRoy Round Lake H.S. Noble Spoelstra, Merle Larson, Walter Worthington H.S. Rock Swanson, Steven & Erickson, Wendell Hills H.S. Rock Stuart Nobles Tiesler, Glen'"" Timko, Terry Titus, Mark O'Conners, WilliamLakefield H.S. Jackson Schweiger, Delbert Jackson H.S. Jackson ,:, County Agricultural Agenl. ''"'' Miss Hansen, 4-H member; Mr. Tiesler, adult farmer. taining and analyzing the data by themselves and pro-duced reports for their club projects. Collectively, their · work produced information of value to the state. There-fore, this project demonstrates that these young people represent a valuable pool of human resources that may be utilized in solving certain scientific problems. References CHIANG, H. C. 1961. Fringe populations of the European corn borer, Pyrausta nubilalis, their characteristics and problems. Ann. Ent. Soc. Amer. 54: 378-387. CHIANG, H. C. and A. C. HODSON. 1959a. Summer pu-pation of the European corn borer and the seasonal temperature. lour. Econ. Ent. 52: 409-411. CHIANG, H. C. and A. C. HODSON. 1959b. Population fluctuations of the European corn borer, Pyrausta nu-bilalis, at Waseca, Minnesota, 1948-1957. Ann . Ent. Soc. Amer. 52: 710-724. CHIANG, H. C., J. C. JARVIS, C. C. BURKHARDT, M. L. FAIRCHILD, G. T. WEEKMAN, and C. A. TRIPLEHORN. l 961. Populations of European corn borer, Ostrinia nubilalis (Hbn.) in field corn, Zea mays (L.) in the north central United States. Missouri Agri. Exp. Sta. Res. Bull. 776 (North Central Reg. Publ. 129) 95 pp. SCHURR, K. M. and F. G. HOLDAWAY. 1964. The rela-tion between plant injury in maize and ovipositional preference of Ostrinia nubilalis ( Hbn.), European corn borer. Proc. Xllth Intern'! Congr. Ent. (Lon-don). Pp. 607-608. STIRRETT, G. M. 1938. A field study of the flight, oviposi-tion, and establishment period in the life cycle of the European corn borer, Pyrausta nubilalis Hbn., and the physical factors affecting them. Sci. Agri. Ottawa, 18: 656-683. 19 

Northerly Movement of Corn Borer Moths in Southern Minnesota

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Northerly Movement of Corn Borer Moths in Southern Minnesota

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