HORTICULTURAL ENTOMOLOGY Integrating Chemical and Biological Control of European Corn Borer in Bell Pepper ANNA V. CHAPMAN, THOMAS P. KUHAR,1 PETER B. SCHULTZ,2 TIMOTHY W. LESLIE,3 3 4 5 SHELBY J. FLEISCHER, GALEN P. DIVELY, AND JOANNE WHALEN Department of Entomology, Virginia Polytechnic Institute & State University, Eastern Shore AREC, Painter, VA 23420 J. Econ. Entomol. 102(1): 287Ð295 (2009) ABSTRACT Using multiple locations and a series of Þeld trials over 2 yr, we evaluated an integrated pest management program for Ostrinia nubilalis (Hu¨ bner) (Lepidoptera: Crambidae) management in peppers involving biorational chemistries, inundative releases of Trichogramma ostriniae (Pang & Chen), and conservation of generalist predators. In small plot trials, three biorational insecticides (spinosad, indoxacarb, and methoxyfenozide) provided comparable control of O. nubilalis as two broad-spectrum conventional insecticides (acephate and lambda-cyhalothrin). However, lambda- cyhalothrin at most locations, and indoxacarb at one location, resulted in outbreaks of green peach aphids. We also observed signiÞcant effects on the generalist predator community: beneÞcial com- munities in methoxyfenozide-treated plots were most similar to untreated controls, and acephate- treated plots were the least similar. Management systems comparing untreated controls, inundative release of T. ostriniae with methoxyfenozide applied when lepidopterans exceeded thresholds, or weekly applications of acephate or lambda-cyhalothrin, showed no effects on marketable fruit or percentage of fruit damaged, but the conventional insecticide approach caused aphid ßares. Inun- dative releases of T. ostriniae and biorational chemistries provide a more environmentally sound approach to managing O. nubilalis in peppers, due, in part, to conservation of generalist predators. KEY WORDS Ostrinia nubilalis, Trichogramma ostriniae, pepper, biocontrol, IPM Sweet bell pepper (Capsicum annuum L.) is a valuable enemies in the agroecosystem, environmental and hu- vegetable crop, grossing nearly $500 million annually man health risks, and reduced proÞts. in the United States (NASS 2006). Commercial grow- For pepper growers in the northeastern and central ers have a large Þnancial investment once plants begin United States, European corn borer, Ostrinia nubilalis to set fruit, and they often apply insecticides preven- (Hu¨ bner) (Lepidoptera: Crambidae), is the primary tatively to protect the pepper fruit from insect pests. target of insecticide sprays (Welty 1995, Hazzard et al. Pepper growers in the Mid-Atlantic United States gen- 2001). The insect has two to three generations per year erally apply the organophosphate acephate for two and is a season-long risk to bell pepper. Egg masses are sprays (maximum allowed per crop per season) and deposited on the undersides of leaves (Barlow and then apply a pyrethroid insecticide every 5Ð10 d until Kuhar 2004). After a brief period of leaf feeding, larvae Þnal harvest. This conventional (preventative spray- bore into fruit if available or stems if no fruit or only ing) approach may result in Þve to 10 insecticide very small immature fruit are present (Hitchner and applications per crop. Although it is generally effec- Ghidiu 2006). Direct damage is caused by the tunnel- tive (Welty 1995, Kuhar and Speese 2002, Kuhar et al. ing larvae that feed on the pericarp, placenta, and 2003), it has numerous drawbacks associated with un- seeds of developing fruit. Moreover, tunnel holes fre- warranted applications, including potential buildup of quently are entry points for fruit-rotting pathogens pesticide residues, destruction of important natural such as Erwinia caratovora (Hazzard et al. 2001). Fruit damage can range from 40 to 60% (Welty 1995, Kuhar and Speese 2002, Kuhar et al. 2003, Welty and Vitanza 2005). Even greater fruit damage can occur to ma- 1 Corresponding author, e-mail: [email protected]. ture (colored) bell peppers because of the in- 2 Hampton Roads AREC, Virginia Tech, Virginia Beach, VA 23455- 3315. creased time that fruit are in the Þeld. O. nubilalis 3 Department of Entomology, Pennsylvania State University, Uni- is particularly difÞcult to control because larvae are versity Park, PA 16802. only exposed to insecticide sprays from egg hatch 4 Department of Entomology, University of Maryland, College until tunneling. Park, MD 20742. 5 Department of Entomology and Applied Biology, University of Other insects that may infest pepper fruit include Delaware, Newark, DE 19717-1303. the noctuid pests Helicoverpa zea (Boddie); Spodopt- 0022-0493/09/0287Ð0295$04.00/0 ᭧ 2009 Entomological Society of America 288 JOURNAL OF ECONOMIC ENTOMOLOGY Vol. 102, no. 1 era exigua Hu¨ bner; Spodoptera frugiperda (J.E. Smith); Materials and Methods and pepper maggot, Zonosemata electa (Say) (Diptera: Biorational Insecticide Trials. We evaluated the Tephritidae) (Boucher and Ashley 2001). However, effects of biorational chemistries on O. nubilalis dam- Kuhar et al. (2004) found that this complex of pests age and natural enemy communities in 2005, by using only accounted for Ϸ5% of insects found attacking bell small-plot Þeld experiments at four locations: Virginia pepper fruit in Virginia, with most (95%) being O. Tech Eastern Shore Agricultural Research and Exten- nubilalis. In addition, green peach aphid, Myzus per- sion Center (AREC), Painter, VA; University of Del- sicae (Sulzer), can be an important indirect pest of aware REC, Georgetown, DE; University of Maryland peppers by feeding on plant phloem sap, reducing Wye REC, Queenstown, MD; and the Russell E. Lar- plant vigor, vectoring viruses, and depositing honey- son Research Farm, Rock Springs, PA. Each Þeld con- dew, where black sooty mold fungus may grow. Green sisted of treatments in a randomized complete block peach aphid has a tremendous reproductive capabil- design with four replications of six insecticide treat- ity, and it can quickly build to damaging levels if ments. Individual plots were four rows wide by 6 m populations are not contained (van Emden et al. long with Ͼ3-m alleys between plots. Crops were 1969). established and maintained using standard agricul- Biological control of O. nubilalis eggs using aug- tural procedures including fertilizer, herbicide, and mentative releases of Trichogramma parasitoids may fungicide applications according to a commercial veg- provide an alternative to reliance on insecticides etable production manual for the Mid-Atlantic United (Smith 1996), and thus help conserve beneÞcials that States (Kuhar et al. 2006b, see Table 1 for details at could regulate aphid densities. Trichogramma ostriniae each location). Insecticide treatments included 1) in- Pang & Chen (Hymenoptera: Trichogrammatidae) doxacarb at 0.072 kg (AI)/ha (Avaunt 30 WG; E. I. du was introduced into the United States from China in Pont de Nemours and Co.); 2) methoxyfenozide at the early 1990s (Hoffmann et al. 1995), and it has 0.112 kg (AI)/ha (Intrepid 2 F; Dow AgroSciences shown promise for controlling O. nubilalis in corn LLC); 3) spinosad at 0.026 kg (AI)/ha (SpinTor 2 SC, (Wang et al. 1999, Hoffmann et al. 2002, Kuhar et al. Dow AgroSciences LLC); 4) acephate at 1.09 kg 2002, Wright et al. 2002) and solanaceous crops (Ku- (AI)/ha (Orthene 97SG; Valent USA Corporation, har et al. 2004). After four to Þve inundative releases Walnut Creek, CA); 5) lambda-cyhalothrin at 0.03 kg of T. ostriniae in bell pepper, O. nubilalis egg parasitism (AI)/ha (Syngenta Crop Protection Inc., Greensboro, Ϸ averaged 50%, and cumulative fruit damage was re- NC); and 6) an untreated control. Insecticides were duced almost 70% compared with nonrelease control applied with a CO2 backpack sprayer with a one-row plots (Kuhar et al. 2004). However, under heavy pest boom having three hollow-cone nozzles per row (one pressure, pepper fruit damage still exceeded 10% in over the top and one drop nozzle on each side) de- the T. ostriniae release plots. livering 39 gpa at 40 psi. Treatments were applied Reduced-risk (biorational) insecticides offer an al- weekly from Þrst fruit until Þnal harvest. Dates of ternative to organophosphates and pyrethroids for applications for each location are presented in Table controlling O. nubilalis in pepper. In recent years, a 1. On three postspray sample dates, aphids were few narrow-spectrum (more lepidopteran speciÞc) counted on 50 randomly picked leaves per plot. Rel- insecticides have been registered for use on bell pep- ative density of natural enemies (generalist arthropod per, including spinosad (Spintor, Dow AgroSciences predators and parasitoid species) were estimated by LLC, Indianapolis, IN), methoxyfenozide (Intrepid, slowly walking the entire length of one middle row per Dow AgroSciences LLC), and indoxacarb (Avaunt, plot while vacuuming plants using a Craftsman 200 E. I. DuPont de Nemours and Co., Wilmington, DE). mph leaf blower-vac. Samples were collected using a These insecticides provide effective control of most Þne mesh bag Þtted on the intake tube of diameter 12 lepidopteran pests, whereas generally having greatly cm. After each sample was collected, bags were tied reduced toxicity to natural enemies (Brunner et al. shut and frozen. Any dirt or plant debris was removed 2001; Elzen 2001; Baur et al. 2003; Hewa-Kapuge et al. and all insects were stored in 70% ethanol for later 2003; Hill and Foster 2003; Schneider et al. 2003; Stude- identiÞcation and sorting into seven natural enemy baker and Kring 2003a, 2003b; Carton et al. 2003; Has- groups: ladybird