Response of Potato Tuber Yield to Stem Injury by European Corn Borer (Lepidoptera: Crambidae) in the Mid-Atlantic United States Author(s): Brian A. Nault, John Speese III, George G. Kennedy, James Linduska, and Galen P. Dively Source: Journal of Economic Entomology, 94(5):1162-1169. Published By: Entomological Society of America DOI: http://dx.doi.org/10.1603/0022-0493-94.5.1162 URL: http://www.bioone.org/doi/full/10.1603/0022-0493-94.5.1162 BioOne (www.bioone.org) is a nonprofit, online aggregation of core research in the biological, ecological, and environmental sciences. BioOne provides a sustainable online platform for over 170 journals and books published by nonprofit societies, associations, museums, institutions, and presses. Your use of this PDF, the BioOne Web site, and all posted and associated content indicates your acceptance of BioOne’s Terms of Use, available at www.bioone.org/page/ terms_of_use. Usage of BioOne content is strictly limited to personal, educational, and non-commercial use. Commercial inquiries or rights and permissions requests should be directed to the individual publisher as copyright holder. BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions, research libraries, and research funders in the common goal of maximizing access to critical research. HORTICULTURAL ENTOMOLOGY Response of Potato Tuber Yield to Stem Injury by European Corn Borer (Lepidoptera: Crambidae) in the Mid-Atlantic United States BRIAN A. NAULT,1 JOHN SPEESE III, GEORGE G. KENNEDY,2 JAMES LINDUSKA,3 4 AND GALEN P. DIVELY Virginia Polytechnic Institute and State University, Eastern Shore Agricultural Research and Extension Center, 33446 Research Drive, Painter, VA 23420 J. Econ. Entomol. 94(5): 1162Ð1169 (2001) ABSTRACT The response of potato, Solanum tuberosum L., tuber yield to stem injury by European corn borer, Ostrinia nubilalis (Hu¨ bner), larvae was investigated in the Mid-Atlantic region of the United States for 3 yr. This response was described for ÔSuperiorÕ, ÔAtlanticÕ, and ÔSnowdenÕ potato, which are early-season, midseason, and late-season maturing cultivars, respectively. To model the yield/injury relationship, a range of corn borer injury levels was established in the Þeld by aug- menting the natural infestation with varying densities of laboratory-reared larvae. Linear and nonlinear regression analyses (plateau and second-order polynomial models) were used to describe the relationship between yield of U.S. No. 1 grade tubers and the percentage of stems injured by corn borer larvae. The maturity of the cultivar did not affect the response of potato yield to stem injury. In nine of 14 experiments, potato tolerated high levels of corn borer injury (55Ð90% of stems injured) without yield loss, suggesting that control of corn borer may not be necessary. Yet, in one of Þve Superior tests, in two of four Atlantic tests and in two of Þve Snowden tests, corn borer injury signiÞcantly reduced yield. Of the Þve data sets in which corn borer injury reduced yield, the plateau model Þt two data sets and the quadratic model Þt one data set. In two of the three cases, these models accounted for nearly identical amounts of total variation in yield as that accounted for by the linear model. The linear model Þt four of the Þve data sets, but the R2 values were low for three of the four tests (0.10, 0.18, and 0.31). The parameter or parameters that interact with corn borer injury to cause tuber yield reduction should be identiÞed before economic injury levels and thresholds are devel- oped. KEY WORDS Ostrinia nubilalis, potato, yield, economic injury level EUROPEAN CORN BORER, Ostrinia nubilalis (Hu¨ bner), occurrences of corn borer infestations. The exception infestations in Irish potato Þelds, Solanum tuberosum to this is in North Carolina where growers typically L., are a major concern to growers in the eastern experience moderate to high corn borer infestations. United States. Until recently, potato producers in In North Carolina, leafhopper and aphid infestations states other than North Carolina rarely encountered are rare and potato beetle populations are managed corn borer damage because infestations were con- using only 1Ð2 foliar insecticide sprays, which are trolled inadvertently by multiple applications of in- frequently timed after applications are made for con- secticides used to manage Colorado potato beetles, trolling corn borer. Currently, corn borer infestations Leptinotarsa decemlineata (Say), potato leafhoppers, are managed using 1Ð2 insecticide applications during Empoasca fabae, and the aphids, Myzus persicae (Sul- the initial phase of neonate establishment in the Þrst zer), Aphis gossypii Glover and Macrosiphum euphor- half of May. biae (Thomas). Since 1995, however, these pests have European corn borer larvae injure potato by boring been managed by a single, in-furrow application of in the stems. A single corn borer larva makes an av- imidacloprid (Admire 2 F, Bayer, Kansas City, KS). erage of nearly Þve tunnels within the plant during its Because imidacloprid does not have activity against development (Nault and Kennedy 1996b). Large lar- European corn borer, it is likely that the widespread vae typically bore within the base of the plant, often use of this product is responsible for more frequent causing the stems to break. Corn borer larvae also are capable of spreading the aerial stem rot pathogen, 1 Department of Entomology, NY State Agricultural Experiment Erwinia caratovora, as it moves from stem to stem Station, Cornell University, Geneva, NY 14456 ([email protected]). (Anderson et al. 1981), but the occurrence of this 2 Department of Entomology, Box 7630, North Carolina State Uni- disease within the past decade has been uncommon versity, Raleigh, NC 27695. (G.G.K., unpublished data). Research in North Caro- 3 Lower Eastern Shore Research and Education Center, University of Maryland, 27664 Nanticoke Road, Salisbury, MD 21801. lina shows that even high infestations of corn borer 4 Department of Entomology, University of Maryland, College have no effect on marketable yield of the cultivars Park, MD 20742. ÔPungoÕ (Kennedy 1983) and ÔAtlanticÕ (Nault and 0022-0493/01/1162Ð1169$02.00/0 ᭧ 2001 Entomological Society of America October 2001 NAULT ET AL.: EFFECT OF O. nubilalis INJURY ON POTATO YIELD 1163 Kennedy 1996a). Similarly, in a one-year study in 219 kg/ha of (25:0:0, N:P:K), 168 kg/ha of (34:0:0, which tuber yields were unusually low, no relation- N:P:K), 112 kg/ha of (34:0:0, N:P:K) and 168 kg/ha of ship between corn borer injury and yield of ÔSuperiorÕ (34:0:0, N:P:K) on 7 May, 2 and 18 June and 8 July, was observed (Kennedy 1983). respectively. In North Carolina, plots received To date, no information exists on the relationship 785 kg/ha of (17:17:17, N:P:K) fertilizer at planting and between corn borer injury and tuber yield for the 224 kg/ha of (34:0:0, N:P:K) on 10 May. Weeds were potato cultivars most commonly grown in the Mid- controlled in Virginia with one application of metribu- Atlantic region of the United States, other than At- zin (0.4 kg [AI]/ha) ϩ metolachlor (1.7 kg [AI]/ha) lantic, and no data exist for other regions. A majority on 26 April 1997, 21 April 1998 and 27 April 1999. In of the potato acreage in the mid-Atlantic comprises of Maryland, weeds were controlled using two applica- Superior, Atlantic. and ÔSnowdenÕ, which are early- tions of linuron (0.45 kg [AI]/ha) ϩ metolachlor (1.1 season (85Ð100 d to harvest), mid-season (100Ð110 to kg [AI]/ha) on 6 May and 13 June 1997; whereas, in harvest) and late-season (115Ð120 d to harvest) ma- North Carolina weeds were managed using one ap- turing cultivars, respectively. The objective of this plication of metribuzin at a rate of 0.8 kg (AI)/ha on study was to describe the relationship between corn 27 March 1997. Foliar diseases were managed in Vir- borer injury and tuber yield for each of these cultivars ginia using mancozeb at a rate of 1.7 kg (AI)/ha on 24 in the Mid-Atlantic region of the United States. May and 5 June, and chlorothalonil at a rate of 1.3 kg (AI)/ha on 18 June 1997; mancozeb was used at a rate of 1.7 kg (AI)/ha on 2 June 1998 and 3 June 1999. In Materials and Methods Maryland, foliar diseases were managed using chlo- Experiments were conducted at Virginia Polytech- rothalonil at a rate of 1.3Ð2.5 kg (AI)/ha on 30 May, 6 nic Institute and State UniversityÕs Eastern Shore Ag- and 18 June, 1, 9, 16, 23 and 29 July 1997. Foliar diseases ricultural Research and Extension Center near were managed in North Carolina using chlorothalonil Painter, VA, from 1997 through 1999, University of at a rate of 1.3 kg (AI)/ha on 2, 9, 16, 23 and 30 May MarylandÕs Lower Eastern Shore Agricultural Re- and 6 and 13 June 1997. search and Education Center in Salisbury, MD, in 1997 Colorado potato beetle, Leptinotarsa decemlineata and North Carolina Department of AgricultureÕs Tide- (Say), infestations were controlled using imidacloprid water Research Station near Roper, NC in 1997. Soil (Admire 2 F [ßowable], 0.2Ð0.3 kg [AI]/ha, Bayer) types at the Virginia, Maryland, and North Carolina either at planting at all sites in 1997 or by foliar sprays sites were Bojac sandy loam, loamy sand and Ports- in late May 1999 (Provado 1.6 F [ßowable], 0.05 kg mouth loam soil, respectively. In 1997 and 1998, the [AI]/ha, Bayer); whereas, Bacillus thuringiensis subsp. cultivars Superior, Atlantic and Snowden were eval- tenebrionis (Novodor [ßowable], 4.67 liters of prod- uated, whereas in 1999 only Superior and Snowden uct/ha, Abbott Laboratories, North Chicago, IL) was were examined.