Life Sciences Commons^™

Georges Brossard, An Advocate For Insects, Stéphane Le Tirant, Brett C. Ratcliffe

Department of Entomology: Faculty Publications

People are strange. They’ve built botanical gardens for plants, planetariums for understanding the planets, zoos for large animals, aviaries for birds, and aquariums for fish, but nothing for insects! It’s as though this class of animals doesn’t count. And yet, of all the creatures on Earth, insects are some of the most important. They are food sources, garbage collectors, decomposers, producers, controllers and pollinators. And what do people do for them in return? We hunt them down with insecticides, pesticides, fungicides and herbicides. It’s time to reconcile humans with insects, a very classy class. I’m going to build a temple …

Economic Injury Levels For Aphis Glycines Matsumura (Hemiptera: Aphididae) On The Soybean Aphid Tolerant Ks4202 Soybean, Lia Marchi-Werle, Edson L.L. Baldin, Hillary D. Fischer, Tiffany Heng-Moss, Thomas Hunt

Department of Entomology: Faculty Publications

The soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is an invasive species from Asia that has been the major economic insect pest of soybeans, Glycine max (L.) Merrill, since 2000. While use of soybeans expressing antibiosis and antixenosis is a well-studied strategy to manage this pest, aphid-tolerant soybeans remain underexplored. This study examined the relationship between cumulative aphid-days (CAD) and yield loss in the tolerant soybean KS4202 during two growing seasons to determine the economic injury levels (EILs) for soybean aphids on KS4202. Soybean aphid infestations were initiated during the soybean reproductive stages. A range of CAD treatments (3,000–45,000 CADs) …

Cross-Resistance And Synergism Bioassays Suggest Multiple Mechanisms Of Pyrethroid Resistance In Western Corn Rootworm Populations, Adriano E. Pereira, Dariane Souza, Sarah N. Zukoff, Lance J. Meinke, Blair D. Siegfried

Department of Entomology: Faculty Publications

Recently, resistance to the pyrethroid bifenthrin was detected and confirmed in field populations of western corn rootworm, Diabrotica virgifera virgifera LeConte from southwestern areas of Nebraska and Kansas. As a first step to understand potential mechanisms of resistance, the objectives of this study were i) to assess adult mortality at diagnostic concentration- LC99 to the pyrethroids bifenthrin and tefluthrin as well as DDT, ii) estimate adult and larval susceptibility to the same compounds as well as the organophosphate methyl-parathion, and iii) perform synergism experiments with piperonyl butoxide (PBO) (P450 inhibitor) and S,S,S-tributyl-phosphorotrithioate (DEF) (esterase inhibitor) in field populations. Most of …

Intraguild Interactions And Behavior Of Spodoptera Frugiperda And Helicoverpa, José P. F. Bentivenha, Débora G. Montezano, Thomas E. Hunt, Edson L.L. Baldin, Julie A. Peterson, Vinicius S. Victor, Luiz E.R. Pannuti, Ana María Vélez, S. Paula-Moraes

Department of Entomology: Faculty Publications

BACKGROUND: Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), is one of the major pests of maize, and is in the same feeding guild of the noctuid pests, Helicoverpa zea (Boddie), and Helicoverpa armigera (Hübner), recently reported in South and North America. The intraguild interactions of these species were assessed in laboratory and field conditions by determining the survival of larvae in interactions scenarios with non-Bt maize silks and ears. Moreover, a video-tracking system was utilized to evaluate behavioral parameters during larval interactions in scenarios with or without food.

silks and ears. Moreover, a video-tracking system was utilized to evaluate behavioral …

Case 3733 – Cetonia Marmorea Olivier, 1789 (Coleoptera: Scarabaeidae: Cetoniinae: Gymnetini): Proposed Conservation By Reversal Of Precedence With Scarabaeus Pulcher Swederus, 1787, Brett C. Ratcliffe

Department of Entomology: Faculty Publications

The purpose of this application, under Article 23.9.3 of the Code, is to conserve the widely used name Gymnetis marmorea (Olivier, 1789), a flower chafer (Scarabaeidae: Cetoniinae) from Trinidad and Tobago, West Indies, which is threatened by the unused senior subjective synonym Scarabaeus pulcher Swederus, 1787. The head of the holotype of Scarabaeus pulcher Swederus, 1787 is excluded from the holotype under Article 73.1.5 of the Code since it is a piece belonging to a Cotinis Burmeister glued to the body of a Gymnetis MacLeay.

Dietary Risk Assessment Of V-Atpase A Dsrnas On Monarch Butterfly Larvae, Huipeng Pan, Xiaowei Yang, Keith Bidne, Richard L. Hellmich, Blair Siegfried, Xuguo Zhou

Department of Entomology: Faculty Publications

By suppressing the expression of genes with essential biological functions, in planta RNAi can negatively affect the development and survival of target pests. As a part of a concerted effort to assess the risks of RNAi transgenic crops on non-target organisms, we developed an in vivo toxicity assay to examine the impacts of ingested dsRNAs incurred to the monarch butterfly, Danaus plexippus (L.), an iconic eco-indicator in North America. To create the worst case scenario, the full-length v-ATPase A cDNAs from the target pest, western corn rootworm, Diabrotica virgifera virgifera, and the non-target D. plexippus were respectively cloned. A 400 …

Microbial Communities Associated With Stable Fly (Diptera: Muscidae) Larvae And Their Developmental Substrates, Erin Scully, Kristina Friesen, Brian Wienhold, Lisa M. Durso

Department of Entomology: Faculty Publications

Bacteria are essential for stable fly (Stomoxys calcitrans (L.)) larval survival and development, but little is known about the innate microbial communities of stable flies, and it is not known if their varied dietary substrates influence their gut microbial communities. This investigation utilized 454 sequencing of 16S and 18S amplicons to characterize and compare the bacterial and eukaryotic microbial communities in stable fly larvae and their developmental substrates. The microbial community of the third-instar stable fly larvae is unambiguously distinct from the microbial community of the supporting substrate, with bacterial communities from larvae reared on different substrates more similar …

Transcriptional Analysis Of Defense Mechanisms In Upland Tetraploid Switchgrass To Greenbugs, Teresa Donze-Reiner, Nathan A. Palmer, Erin D. Scully, Travis J. Prochaska, Kyle G. Koch, Tiffany Heng-Moss, Jeffery D. Bradshaw, Paul Twigg, Keenan Amundsen, Scott E. Sattler, Gautam Sarath

Department of Entomology: Faculty Publications

Background: Aphid infestation of switchgrass (Panicum virgatum) has the potential to reduce yields and biomass quality. Although switchgrass-greenbug (Schizaphis graminum; GB) interactions have been studied at the whole plant level, little information is available on plant defense responses at the molecular level.

Results: The global transcriptomic response of switchgrass cv Summer to GB was monitored by RNA-Seq in infested and control (uninfested) plants harvested at 5, 10, and 15 days after infestation (DAI). Differentially expressed genes (DEGs) in infested plants were analyzed relative to control uninfested plants at each time point. DEGs in GB-infested plants induced …

Performance Of Seed Treatments And In-Furrow At-Plant Insecticides For Protection Against Cry3bb1-Resistant Western Corn Rootworm, 2015, Jonas Victor De Macedo,, Kayla A. Mollet, Julie A. Peterson

Department of Entomology: Faculty Publications

The western corn rootworm is an important pest of corn that can compromise yield by feeding on plant roots during its larval stage. WCRW management has been complicated by the development of resistance in some regions, including Nebraska, to transgenic Bacillus thuringiensis (Bt) traits, particularly the protein Cry3Bb1, which confers cross-resistance to mCry3A. A field trial was established to evaluate the efficacy of neonicotinoid seed treatments in combination with in-furrow insecticides on a corn hybrid expressing mCry3A Bt proteins against corn rootworm in an area with a history of rootworm resistance. The trial was conducted in a farmer’s field in …

Farmers’ Perspectives On Resistance In Western Corn Rootworm To Crw-Bt Corn In Midwest Usa, David A. Andow, Robert Wright, Erin W. Hodgson, Thomas E. Hunt, Ken Ostlie

Department of Entomology: Faculty Publications

Resistance in western corn rootworm to transgenic corn hybrids was first confirmed in 2011 in Midwestern USA, and threatens their continued use. Farmers are often the first line of resistance detection, so their understanding and attitudes toward this issue are critical for improving resistance management. We conducted telephone focus groups during 2013 with farmers who had experienced rootworm resistance. There were four stages in dealing with unexpected rootworm injury: Awareness of a problem, diagnosis, confirmation, and recommendations. Most farmers discovered the problem themselves, but this usually happened too late in the growing season to limit yield loss. Once aware of …

Attack And Defense Movements Involved In The Interaction Of Spodoptera Frugiperda And Helicoverpa Zea (Lepidoptera: Noctuidae), José P. F. Bentivenha, Edson L.L. Baldin, Débora G. Montezano, Thomas E. Hunt, Silvana L. Paula-Moraes

Department of Entomology: Faculty Publications

The fall armyworm, Spodoptera frugiperda (J. E. Smith) and the corn earworm, Helicoverpa zea (Boddie) are among the main pests of maize. Both species exhibit cannibalistic behavior and quite often share the same feeding guild in maize (maize ears), which can result in several interspecific and intraspecific interactions. Paired interaction scenarios of intraspecific and interspecific larvae were assessed in arenas in the presence and absence of food to characterize movements resulting from interactions of these insects. There was a difference in the frequency of behavioral movements in all the interactions, except for S. frugiperda in the presence of food. Head …

Effect Of Metarhizium Anisopliae (Ascomycete), Cypermethrin, And D-Limonene, Alone And Combined, On Larval Mortality Of Rhipicephalus Sanguineus (Acari: Ixodidae), Omar Francisco Prado-Rebolledo, Jaime Molina-Ochoa, Roberto Lezama-Gutierrez, Luis Jorge Garcia-Marquez, Yureida B. Minchaca-Llerenas, Eduardo Morales-Barrera, Guillermo Tellez, Billy Hargis, S. R. Skoda, John E. Foster

Department of Entomology: Faculty Publications

The effect of the fungus Metarhizium anisopliae Ma14 strain, D-limonene, and cypermethrin, alone and combined, on the mortality of Rhipicephalus sanguineus Latreille larvae was evaluated. Eight separate groups with 25 tick larvae were inoculated with the fungus, cypermethrin, and D-limonene, and four groups were used as untreated controls. The groups were inoculated with serial dilutions of each treatment material: for example, conidial concentrations were 1 x 10¹, 1 x 10², 1 x 10³, 1 x 10⁴, 1 x 10⁵, 1 x 10⁶, 1 x 10⁷, and …

Influence Of Calcareous Soil On Cry3bb1 Expression And Efficacy In The Field, David S. Wangila, Arnubio Valencia, Haichuan Wang, Blair D. Siegfried, Lance Meinke

Department of Entomology: Faculty Publications

Greater than expected injury by western corn rootworm (WCR) (Diabrotica virgifera virgifera LeConte) to Cry3Bb1 expressing maize hybrids (Zea mays L.) has been reported in southwestern Nebraska. Affected areas of some fields are often associated with high pH calcareous soils where maize growth is poor and iron chlorosis is common. As part of a comprehensive study to understand potential causes of unexpected injury, experiments were conducted during 2013 and 2014 to ascertain whether the calcareous soil conditions and associated poor maize growth negatively affect the expression of Cry3Bb1. Quantitative determination of Cry3Bb1 protein expression levels in root tissues …

Description Of The Female Of Hologymnetis Reyesi Gasca And Deloya (Coleoptera: Scarabaeidae: Cetoniinae: Gymnetini), With New State Records For Mexico And A Bilingual Key To The Species Of Hologymnetis Martínez, Brett C. Ratcliffe, Hector Jaime Gasca-Alvarez, Cuauhtemoc Deloya

Department of Entomology: Faculty Publications

The female of Hologymnetis reyesi Gasca and Deloya is described and illustrated for the first time based upon specimens from Estado de México, Mexico, new state record. The species is also herein reported from the state of Guerrero, new state record. A bilingual key in Spanish and English to all the species of Hologymnetis Martínez is presented and accompanied by maps showing distributions for all species in the genus.

Obituary And Bibliography Of Norm Penny (1946-2016), An “Entomologist’S Entomologist”, Robert L. Zuparko, Brett C. Ratcliffe

Department of Entomology: Faculty Publications

The section “Remembrances of Norm Penny” was authored by BCR, and the remaining sections by RLZ. Fabio Penny and Rachel Diaz-Bastin made valuable additions to the text.

Norman Dale Penny, collection manager emeritus in the Department of Entomology at the California Academy of Sciences, San Francisco, California, and past president of the Pacifi c Coast Entomological Society, died of a stroke on July 10, 2016. That weekend he and his wife were near Quincy, in Plumas County, California, collecting Mecoptera for DNA retrieval to help elucidate the phylogeny of the group. After collecting his targeted species, he suffered a severe …

Using Publicly Available Data To Quantify Plant–Pollinator Interactions And Evaluate Conservation Seeding Mixes In The Northern Great Plains, Clint R.V. Otto, S. O'Dell, R. B. Bryant, N. H. Euliss Jr., R. M. Bush, Matthew D. Smart

Department of Entomology: Faculty Publications

Concern over declining pollinators has led to multiple conservation initiatives for improving forage for bees in agroecosystems. Using data available through the Pollinator Library (npwrc.usgs.gov/pollinator/), we summarize plant–pollinator interaction data collected from 2012–2015 on lands managed by the U.S. Fish and Wildlife Service and private lands enrolled in U.S. Department of Agriculture conservation programs in eastern North Dakota (ND). Furthermore, we demonstrate how plant–pollinator interaction data from the Pollinator Library and seed cost information can be used to evaluate hypothetical seeding mixes for pollinator habitat enhancements. We summarize records of 314 wild bee and 849 honey bee (Apis mellifera …

Modeling Microorganism Transmission With Madagascar Hissing Cockroaches: An Inquiry Activity, Hillary Guzik, Kessler Mccoy-Simandle

Department of Entomology: Faculty Publications

Students will test Madagascar hissing cockroach’s capacity as a vector for transmission of microorganisms. By comparing a cockroach exposed to human contact (handled by students) and a cockroach with limited exposure (not handled), students can assess the ability of cockroaches to transmit microorganisms from one location (hands) to another (agar plate where the microorganism will be grown). This will allow students to determine if the Madagascar hissing cockroach, the classroom pet, is a potential vector for microorganisms. Students then will be able to question and relate the concept of insects and objects as vectors for common pathogen transfer.

Atp-Sensitive Inwardly Rectifying Potassium Channel Regulation Of Viral Infections In Honey Bees, Scott T. O'Neal, Daniel R. Swale, Troy D. Anderson

Department of Entomology: Faculty Publications

Honey bees are economically important pollinators of a wide variety of crops that have attracted the attention of both researchers and the public alike due to unusual declines in the numbers of managed colonies in some parts of the world. Viral infections are thought to be a significant factor contributing to these declines, but viruses have proven a challenging pathogen to study in a bee model and interactions between viruses and the bee antiviral immune response remain poorly understood. In the work described here, we have demonstrated the use of flock house virus (FHV) as a model system for virus …

Weight Of Evidence Evaluation Of A Network Of Adverse Outcome Pathways Linking Activation Of The Nicotinic Acetylcholine Receptor In Honey Bees To Colony Death, Carlie A. Lalone, Daniel L. Villeneuve, Judy Wu-Smart, Rebecca Y. Milsk, Keith Sappington, Kristina V. Garber, Justin Housenger, Gerald T. Ankley

Department of Entomology: Faculty Publications

Ongoing honey bee (Apis mellifera) colony losses are of significant international concern because of the essential role these insects play in pollinating crops. Both chemical and non-chemical stressors have been implicated as possible contributors to colony failure; however, the potential role(s) of commonly-used neonicotinoid insecticides has emerged as particularly concerning. Neonicotinoids act on the nicotinic acetylcholine receptors (nAChRs) in the central nervous system to eliminate pest insects. However, mounting evidence indicates that neonicotinoids also may adversely affect beneficial pollinators, such as the honey bee, via impairments on learning and memory, and ultimately foraging success. The specific mechanisms linking …

Agronomic Potential Of Using Precipitated Calcium Carbonate On Early Plant Growth And Soil Quality In The Intermountain West - Greenhouse Studies, Gary W. Hergert, Murali K. Darapuneni, Abdullah M. Aqeel, Robert G. Wilson, Robert M. Harveson, Jeff D. Bradshaw, Rex A. Nielsen

Department of Entomology: Faculty Publications

Storage and management of large piles of precipitated calcium carbonate (PCC) from sugarbeet processing are a challenge in the western US. Potential uses of this product on surrounding agricultural lands in western NE, eastern WY and northeast CO requires an evaluation of chemical and agronomic impacts of PCC on soils and crop growth. A preliminary greenhouse study was conducted in Scottsbluff, NE using 10 soils from the 3 states. Soils were mixed with 11, 22, 33 and 44 Mg ha^-1 rates of PCC to test the early plant growth of sugarbeet, corn, and dry bean in addition to determining …

Population Dynamics Of The Wheat Curl Mite (Acari: Eriophyidae) During The Heading Stages Of Winter Wheat, Anthony J. Mcmechan, Gary Hein

Department of Entomology: Faculty Publications

The wheat curl mite (Aceria tosichella Keifer) is the only known vector of three viruses in wheat—Wheat streak mosaic virus, Wheat mosaic virus, and Triticum mosaic virus. The economic impact of this disease complex is linked to the presence of suitable hosts prior to winter wheat maturing in early summer and the movement of wheat curl mite from wheat to oversummering hosts prior to wheat harvest. Previous research has documented the prevalence and density of mite populations on maturing wheat heads; however, these studies were limited to a few late stages of wheat. A study was conducted …

Wheat Streak Mosaic Virus Coat Protein Is A Determinant For Vector Transmission By The Wheat Curl Mite, Satyanarayana Tatineni, Anthony J. Mcmechan, Gary L. Hein

Department of Entomology: Faculty Publications

Wheat streak mosaic virus (WSMV; genus Tritimovirus; family Potyviridae), is transmitted by the wheat curl mite (Aceria tosichella Keifer). The requirement of coat protein (CP) for WSMV transmission by the wheat curl mite was examined using a series of viable deletion and point mutations. Mite transmission of WSMV was completely abolished with deletions comprising CP amino acids 58–100. In contrast, the amino-proximal (amino acids 6–27 and 36–57) and carboxy-terminal (14 amino acids) regions of CP were expendable for mite transmission. Mutation of aspartic acid residues at amino acid positions 289 or 326 (D289A or D326A) at the …

The Fourteenth Amithao Thomson, 1878 (Coleoptera: Scarabaeidae: Cetoniinae: Gymnetini): A Remarkable New Species From Ecuador, Brett C. Ratcliffe

Department of Entomology: Faculty Publications

Anew species in the Neotropical genus Amithao Thomson, 1878 is described from Ecuador, with supporting illustrations and a diagnosis. A revised key to the 14 species in the genus is provided along with an annotated checklist.

A New Species Of Golofa Hope, 1837 (Coleoptera: Scarabaeidae: Dynastinae) From Peru, Brett C. Ratcliffe, Stéphane Le Tirant

Department of Entomology: Faculty Publications

A new species of Golofa Hope is described from Peru along with supporting illustrations and a diagnosis.

Se describe una nueva especie de Golofa Hope de Peru soportado por ilustraciones y diagnosis.

Sublethal Effects Of Vatpase-A And Snf7 Dsrnas On Biology Of Southern Corn Rootworm, Diabrotica Undecimpunctata Howardi Barber, Adriano E. Pereira, Ana María Vélez, Lance J. Meinke, Blair D. Siegfried

Department of Entomology: Faculty Publications

RNA interference is a powerful tool against corn rootworm. Adults and neonates of southern corn rootworm, Diabrotica undecimpunctata howardi Barber (Coleoptera: Chrysomelidae), were exposed to the LC₅₀ of vATPase-A and Snf7 double-stranded RNAs (dsRNAs), and the effects on female fecundity, egg viability, male fitness as measured by sperm viability and mating capacity, larval recovery along with dry weight, and instar determination 10 d after exposure to dsRNA, were determined. Significant reductions were observed for a number of parameters in dsRNA-exposed rootworms relative to control treatments. Female fecundity and larval recovery were significantly reduced after exposure to both dsRNAs. In …

Effects Of Neonicotinoid Imidacloprid Exposure On Bumble Bee (Hymenoptera: Apidae) Queen Survival And Nest Initiation, Judy Wu-Smart, Marla Spivak

Department of Entomology: Faculty Publications

Neonicotinoids are highly toxic to insects and may systemically translocate to nectar and pollen of plants where foraging bees may become exposed. Exposure to neonicotinoids can induce detrimental sublethal effects on individual and colonies of bees and may have long-term impacts, such as impaired foraging, reduced longevity, and reduced brood care or production. Less well-studied are the potential effects on queen bumble bees that may become exposed while foraging in the spring during colony initiation. This study assessed queen survival and nest founding in caged bumble bees [Bombus impatiens (Cresson) (Hymenoptera: Apidae)] after chronic (18-d) dietary exposure of imidacloprid …

Evaluation Of Smartstax And Smartstax Pro Maize Against Western Corn Rootworm And Northern Corn Rootworm: Efficacy And Resistance Management, Graham P. Head, Matthew W. Carroll, Sean P. Evans, Dwain M. Rule, Alan R. Willse, Thomas L. Clark, Nicholas P. Storer, Ronald D. Flannagan, Luke W. Samuel, Lance Meinke

Department of Entomology: Faculty Publications

Background: Cases of western corn rootworm (WCR) field-evolved resistance to Cry3Bb1 and other corn rootworm (CRW) control traits have been reported. Pyramid products expressing multiple CRW traits can delay resistance compared to single trait products. We used field studies to assess the pyramid CRW corn products, SmartStax (expressing Cry3Bb1 and Cry34Ab1/Cry35Ab1) and SmartStax PRO (expressing Cry3Bb1, Cry34Ab1/Cry35Ab1 and DvSnf7), at locations with high WCR densities and possible Cry3Bb1 resistance, and to assess the reduction in adult emergence attributable to DvSnf7 and other traits. Insect resistance models were used to assess durability of SmartStax and SmartStax PRO to WCR resistance.

Results: …

Identification, Biology, Impacts, And Management Of Stink Bugs (Hemiptera: Heteroptera: Pentatomidae) Of Soybean And Corn In The Midwestern United States, Robert L. Koch, Daniela T. Pezzini, Andrew P. Michel, Thomas Hunt

Department of Entomology: Faculty Publications

Stink bugs (Hemiptera: Heteroptera: Pentatomidae) are an emerging threat to soybean and corn production in the midwestern United States. An invasive species, the brown marmorated stink bug, Halyomorpha halys (Sta° l), is spreading through the region. However, little is known about the complex of stink bug species associated with corn and soybean in the midwestern United States. In this region, particularly in the more northern states, stink bugs have historically caused only infrequent impacts to these crops. To prepare growers and agricultural professionals to contend with this new threat, we provide a review of stink bugs associated with soybean and …

Method Development For Monitoring Bean Leaf Beetle, Cerotoma Trifurcata (Forster) (Coleoptera: Chrysomelidae), Susceptibility To Thiamethoxam Seed Treatments On Soybeans, Chelsea L. Tietjen, Thomas Hunt, Daniel D. Snow, David A. Cassada, Blair D. Siegfried

Department of Entomology: Faculty Publications

The increased use of thiamethoxam seed treatments for controlling pests such as the bean leaf beetle, Cerotoma trifurcata (Forster) (Coleoptera: Chrysomelidae), suggests the need for methods to measure and monitor the development of resistance to thiamethoxam. The objectives of this study were to develop a bioassay method that can be used to monitor bean leaf beetle susceptibility to thiamethoxam, and to quantify the relative concentrations of thiamethoxam and clothianidin in early growth stage soybean tissue treated with thiamethoxam as a seed treatment. Overwintered and F1 bean leaf beetles were collected from alfalfa and soybean fields and used in excised soybean …

Yield Response Of Tolerant And Susceptible Soybean To The Soybean Aphid, Lia Marchi-Werle, Renata Ramos Pereira, John C. Reese, Thomas Hunt

Department of Entomology: Faculty Publications

Soybean aphid, Aphis glycines (Hemiptera: Aphididae), is the most economically important soybean [Glycine max (L.) Merr.] pest of North America. Multiple studies have identified soybean expressing antibiosis and/or antixenosis; however, soybean tolerance remains underexplored. Tolerance to soybean aphid injury was previously identified in soybean KS4202. This research examined the yield response of KS4202 infested with soybean aphid at specific plant stages and identified at what plant stage tolerance initiates. A preliminary study evaluated the yield parameters of the tolerant genotype at low (4000– 5500 cumulative aphid-days [CAD]) and high aphid pressure (7500–8500 CAD) at different growth stages (V1, V3, …