Rick L. Brandenburg

Trapping Phyllophaga spp. (Coleoptera: Scarabaeidae: Melolonthinae) in the United States and Canada using sex attractants.

Abstract The sex pheromone of the scarab beetle, Phyllophaga anxia, is a blend of the methyl esters of two amino acids, L-valine and L-isoleucine. A field trapping study was conducted, deploying different blends of the two compounds at 59 locations in the United States and Canada. More than 57,000 males of 61 Phyllophaga species (Coleoptera: Scarabaeidae: Melolonthinae) were captured and identified. Three major findings included: (1) widespread use of the two compounds [of the 147Phyllophaga (sensu stricto) species found in the United States and Canada, males of nearly 40% were captured]; (2) in most species intraspecific male response to the pheromone blends was stable between years and over geography; and (3) an unusual pheromone polymorphism was described from P. anxia. Populations at some locations were captured with L-valine methyl ester alone, whereas populations at other locations were captured with L-isoleucine methyl ester alone. At additional locations, the L-valine methyl ester-responding populations and the L-isoleucine methyl ester-responding populations were both present, producing a bimodal capture curve. In southeastern Massachusetts and in Rhode Island, in the United States, P. anxia males were captured with blends of L-valine methyl ester and L-isoleucine methyl ester. Resumen La feromona sexual del escarabajo, Phyllophaga anxia, es una mezcla de los ésteres metílicos de dos aminoácidos, L-valina y L-isoleucina. Se condujo un estudio de campo usando diferentes mezclas de los dos componentes en 59 sitios de Estados Unidos y Canada. Más de 57,000 machos de 61 especies dePhyllophaga fueron capturados e identificados. Tres de los resultados más importantes incluyen: (1) el extenso uso de los dos componentes [de las 147 especies de Phyllophaga (sensu stricto), en Estados Unidos y Canada, fueron capturados machos de cerca del 40% de ellas.]; (2) para la mayoría de las especies, la respuesta intraespecífica de los machos a las combinaciones de los dos aminoácidos fue consistente entre años diferentes, y en todos los sitios geográficos; y (3) un inusual polymorfismo de la feromona fue descrito para P. anxia. Poblaciones de algunos sitios fueron atrapados sólo con valina, mientras que poblaciones de otros sitios fueron atrapados sólo con isoleucina. También se encontraron sitios donde las poblaciones responden a ambos componentes, valina e isoleucina, produciendo una curva de captura bimodal. En el sureste del estado de Massachusetts y en Rhode Island, en Estados Unidos, machos de P. anxia fueron atrapados en trampas con mezclas de valina e isoleucina.

Tunneling Responses of Mole Crickets (Orthoptera: Gryllotalpidae) to the Entomopathogenic Fungus, Beauveria bassiana

Abstract Greenhouse studies of mole cricket tunneling architecture were conducted with adult southern, Scapteriscus borellii Giglio-Tos and tawny, Scapteriscus vicinus Scudder, mole crickets exposed to Beauveria bassiana (Balsamo) Vuillemin. Three different strains of B. bassiana as well as the commercially available insecticide Talstar (bifenthrin) were evaluated for avoidance behaviors by examining tunneling characteristics. Each treated container was inspected 24 h after treatment for specific tunneling behaviors in association with the presence of a control agent and the cricket’s response to the conidia or chemical. One of the B. bassiana strains tested, DB-2, caused changes in mole cricket behavior, including significantly less new surface tunneling, fewer vertical tunnels descending into the soil, less tunneling along the perimeter of the containers, and significantly more occurrences of the crickets remaining in an area that reduced exposure to the conidia. Two of the other treatments, strain 10-22 and Talstar, produced some of these same altered behaviors in mole crickets. Mole crickets exposed to a third strain of B. bassiana, BotaniGard, as well as two carrier formulations did not exhibit these same levels of avoidance. These observations indicate that the presence of environmentally “friendly” control agents, such as entomogenous fungi, may affect pest behavior, and strain selection may be critical to eliminate detection and avoidance by the target insect.

Peanut response to cultivar selection, digging date, and tillage intensity

reduced tillage systems often do not exceed those of conventional tillage. Determining the cause of inconsisPeanut (Arachis hypogaea L.) in the United States is generally tent yield response to reduced tillage would be benefigrown in conventionally tilled systems. However, interest in reduced tillage peanut production has increased. Five experiments were concial in determining when reduced tillage systems could ducted in North Carolina to determine if cultivar selection and digging be successfully implemented in peanut production. date affected peanut yield and economic value when peanut was Cultivar selection can have a dramatic effect on crop seeded into conventionally tilled seedbeds compared with strip tillage response to production and pest management practices. into small-grain cover crop or stubble from the crop planted the preCulpepper et al. (1997) reported that peanut cultivars vious summer. In separate experiments, peanut yield and economic responded differently to the plant growth regulator provalue in these tillage systems were compared with peanut strip-tilled hexadione calcium (calcium salt of 3,5-dioxo-4-propiointo beds prepared the previous fall (stale seedbeds). Cultivar selection nylcyclohexanecarboxylic acid). Cultivars also respond and digging date did not affect pod yield or gross value when compardifferently to digging date (Jordan et al., 1998). Disease ing tillage systems. Pod yield in conventional and stale seedbed sysmanagement approaches can be affected by cultivar setems was similar in all five experiments where these systems were compared, and yields in these tillage systems exceeded those of strip lection (Bailey, 2002). Virginia market-type cultivars vary tillage into crop stubble in three of five experiments. Pod yield was considerably in pod size, maturity, and several other agrosimilar among all three tillage systems in the other two experiments. nomic factors (Swann, 2002). Although not well estabIn experiments where only conventional tillage and strip tillage syslished in the literature, pod loss can be severe if peanut tems were compared, pod yield was similar between the two tillage is dug under poor soil conditions (Beam et al., 2002). systems in four experiments, higher in conventional tillage compared It is suspected that pod loss may be greater in reduced with strip tillage in one experiment, and higher for strip tillage comtillage systems than conventional tillage systems bepared with conventional tillage in one experiment. In 16 of 17 comcause the plants may be more difficult to dig. Peanut parisons, pod yield of peanut planted in conventional tillage systems cultivars with larger pods may be more susceptible to equaled or exceeded that of peanut planted into stubble from the digging losses compared with smaller-seeded cultivars previous crop. because they have a greater surface area, which may cause increased exposure to detachment during the digging process. Practitioners indicate that pod loss from P in the United States is typically grown in smaller-seeded runner market types is less than that for conventionally tilled systems (Sholar et al., 1995). large-seeded virginia market types during the digging Peanut response to reduced tillage has been inconsiscomponent of the harvest process. However, these comtent. Research suggests that yields in reduced tillage sysparisons have not been documented in the literature. tems can be lower than (Brandenburg et al., 1998; Cox Determining if pod yield differs among tillage systems and Sholar, 1995; Grichar, 1998; Jordan et al., 2001; for cultivars with different pod sizes may help explain Sholar et al., 1993; Wright and Porter, 1995) or similar inconsistent peanut response to reduced tillage systems. to (Baldwin and Hook, 1998; Dowler et al., 1999; HartStale seedbed crop production has been successful zog et al., 1998; Williams et al., 1998) yields in convenfor a variety of row crops, including soybean [Glycine tional tillage systems. Higher yields in reduced tillage max (L.) Merr.] and cotton (Gossypium hirsutum L.) systems have been associated with lower incidence of (Shaw, 1996). Seedbeds are prepared the previous fall tomato spotted wilt virus (TSWV) (Baldwin and Hook, or during the spring several weeks or months before 1998; Johnson et al., 2001; Wright et al., 2000). In most seeding directly into previously established stale seedexperiments where this disease is not a factor, yields in bed without significant soil disturbance. This approach to peanut production may be a viable alternative to both D.L. Jordan, P.D. Johnson, and A.S. Culpepper, Dep. of Crop Sci., conventional tillage systems and strip tillage directly Box 7620, North Carolina State Univ., Raleigh, NC 27695-7620; J.S. into stubble from the previous crop. Barnes, Peanut Belt Res. Stn., North Carolina Dep. of Agric. and The objectives of this research were to determine if Consumer Serv., Box 220, Lewiston-Woodville, NC 27849; C.R. Bogle, Dep. of Soil Sci., North Carolina State Univ., Upper Coastal Plain peanut response to tillage was associated with cultivar Res. Stn., Box 7619, Raleigh, NC 27695 and North Carolina Dep. of selection and digging date and if peanut yield in stale Agric. and Consumer Serv., Rt. 2 Box 400, Rocky Mount, NC 27801; seedbeds differs from yield in conventional tillage or R.L. Brandenburg, Dep. of Entomol., Box 7613, North Carolina State strip tillage into crop stubble. Univ., Raleigh, NC 27695-7613; and J.E. Bailey, Dep. of Plant Pathol., Box 7616, North Carolina State Univ., Raleigh, NC 27695-7616. ReAbbreviations: CBR, Cylindrocladium black rot; %ELK, percentage ceived 11 Apr. 2002. *Corresponding author (david_jordan@ncsu.edu). of extra large kernels; %TSMK, percentage of total sound mature kernels; TSWV, tomato spotted wilt virus. Published in Agron. J. 95:380–385 (2003).

Role of Insecticides in Reducing Thrips Injury to Plants and Incidence of Tomato Spotted Wilt Virus in Virginia Market-Type Peanut

Abstract Tomato spotted wilt virus (family Bunyaviridae, genus Tospovirus, TSWV), transmitted by many thrips species, is a devastating pathogen of peanut, Arachis hypogaea L. TSWV has become a serious problem in the Virginia/Carolina peanut-growing region of the United States. During 2002, TSWV was present in 47% of the North Carolina hectarage and caused a 5% yield reduction in Virginia. Factors influencing levels of TSWV in runner market-type peanut cultivars, which are primarily grown in Alabama, Flordia, Georgia, and Texas, have been integrated into an advisory to help those peanut growers reduce losses. An advisory based on the southeast runner market-type version is currently under development for virginia market-type peanut cultivars that are grown primarily in the Virginia/Carolina region. A version based on preliminary field experiments was released in 2003. One factor used in both advisories relates to insecticide use to reduce the vector populations and disease incidence. This research elucidated the influence of insecticides on thrips populations, thrips plant injury, incidence of TSWV, and pod yield in virginia market-type peanut. Eight field trials from 2003 to 2005 were conducted at two locations. In-furrow application of aldicarb and phorate resulted in significant levels of thrips control, significant reductions in thrips injury to seedlings, reduced incidence of TSWV, and significant increases in pod yield. Foliar application of acephate after aldicarb or phorate applied in the seed furrow further reduced thrips plant injury and incidence of TSWV and improved yield. These findings will be used to improve the current virginia market-type TSWV advisory.

Effect of Soil Moisture on Ovipositional Behavior in the Southern Mole Cricket (Orthoptera: Gryllotalpidae)

Abstract The relationship between soil moisture and oviposition in an edaphic insect pest, the southern mole cricket, Scapteriscus borellii Giglio-Tos, was studied in a series of greenhouse experiments. Adults were captured in acoustic calling traps and associated pitfall traps during spring flights in southeastern North Carolina in 1996, 1997, and 1998. Female mole crickets were individually confined in chambers containing 2, 4, 7, 10, and 12% soil moisture. Oviposition and mortality were monitored daily. A significant linear relationship between oviposition and soil moisture was indicated by an increase in the number of crickets ovipositing in response to higher soil moisture levels. Additionally, a delay in oviposition was observed as a response to low soil moisture. There were no significant differences in the number of eggs per ovipositing female, indicating that when oviposition does take place, the individual response of the female is to lay a similar number of eggs regardless of moisture levels. The ovipositional response to a rapid increase in soil moisture was also examined. The rapid increase in moisture resulted in a significantly greater percentage of females ovipositing, as seen in the previous experiments.

Entomopathogenic fungi detection and avoidance by mole crickets (Orthoptera: Gryllotalpidae).

Abstract A chamber to monitor mole cricket behavior was designed using two different soil-filled containers and photosensors constructed from infrared emitters and detectors. Mole crickets (Scapteriscus spp.) were introduced into a center tube that allowed them to choose whether to enter and tunnel in untreated soil or soil treated with Beauveria bassiana (Balsamo) Vuillemin. Each time the cricket passed through the photosensor located near the entrance of soil-filled containers, the infrared light was blocked and the exact moment that this occurred was logged onto a computer using custom-written software. Data examined included the first photosensor trigger, total number of sensor triggers, presence of tunneling, and final location of the cricket after 18 h. These behaviors were analyzed to discern differences in mole cricket behavior in the presence of different treatments and to elucidate the mechanism that mole crickets use to detect fungal pathogens. The first study examined substrate selection and tunneling behavior of the southern mole cricket, Scapteriscus borellii Giglio-Tos, to the presence of five strains of B. bassiana relative to a control. There were no differences between the first sensor trigger and total number of triggers, indicating the mole crickets are not capable of detecting B. bassiana at a distance of 8 cm. Changes in mole cricket tunneling and residence time in treated soil occurred for some strains of B. bassiana but not others. One of the strains associated with behavioral changes in the southern mole cricket was used in a second experiment testing behavioral responses of the tawny mole cricket, S. vicinus Scudder. In addition to the formulated product of this strain, the two separate components of that product (conidia and carrier) and bifenthrin, an insecticide commonly used to control mole crickets, were tested. There were no differences in mole cricket behavior between treatments in this study. The differences in behavioral responses between the two species could suggest a more sensitive chemosensory recognition system for southern mole crickets.

Effect of Combining Imidacloprid and Diatomaceous Earth with Beauveria bassiana on Mole Cricket (Orthoptera: Gryllotalpidae) Mortality

Sublethal doses of three orthopteran-derived strains of Beauveria bassiana (Balsamo) Vuillemin were topically applied to adult southern mole crickets, Scapteriscus borellii Giglio-Tos (Orthoptera: Gryllotalpidae), and tested in combination with substrate treatments of diatomaceous earth (DE) and imidacloprid. Crickets treated only with the high doses (10(8) conidia per cricket) of each of the three B. bassiana strains exhibited the shortest survival times as well as the highest percentage mortality at 28 d after treatment. However, these treatments did.not differ significantly from any of the diatomaceous earth combination treatments. Two of the strains tested, 5977 and 3622, exhibited synergistic interactions with DE, whereas the third strain, GHA, was not significant for synergy. Mortality caused by the combination treatment was still greater than the expected additive effect. DE abrades the insect cuticle and absorbs cuticular lipids, aiding the entry of germinating conidia into the mole cricket hemocoel. None of the three strains exhibited synergy when combined with imidacloprid, and mortality of all combination treatments was less than additive. For strain 5977, there was an antagonistic interaction with imidacloprid. It was difficult to obtain <30% mortality for imidacloprid only treatments, which was considered the upper limit for sublethal doses. The mean percentage mortality caused by imidacloprid was 37.5%, and this high percentage made it difficult for any combination treatment to cause significantly more mortality than the expected additive effect. These results clarify the interactions of other control products with B. bassiana and provide a basis for a reduced pesticide approach to mole cricket control.

Interactions of Clethodim and Sethoxydim with Selected Agrichemicals Applied to Peanut

Experiments were conducted in North Carolina during 2002 and 2003 to evaluate broadleaf signalgrass and large crabgrass control by clethodim and sethoxydim applied in two-, three-, or four-way mixtures with fungicides, insecticides, and foliar fertilizer–plant growth regulator treatments. Broadleaf signalgrass and large crabgrass control by clethodim and sethoxydim was not reduced by the insecticides esfenvalerate, indoxacarb, or lambda-cyhalothrin. The fungicides azoxystrobin, chlorothalonil, pyraclostrobin, and tebuconazole reduced large crabgrass control by clethodim or sethoxydim in one or more of three experiments for each herbicide. Disodium octaborate and the plant growth regulator prohexadione calcium plus urea ammonium nitrate (UAN) mixed with clethodim and fungicides improved large crabgrass control in some experiments. In contrast, prohexadione calcium plus UAN and disodium octaborate did not affect broadleaf signalgrass or large crabgrass control by sethoxydim. Nomenclature: Azoxystrobin, methyl (E)-2-{2-[6-(2-cyanophenoxy) pyrimidin-4-yloxy]phenyl}-3-methoxyacrylate; chlorothalonil, tetrachloroisophthalonitrile; clethodim; esfenvalerate, (S)-cyano (3-phenoxyphenyl) methyl (S)-4-chloro-α-(1-methylethyl)benzenacetate; indoxacarb, (S)-methyl 7-chloro-2,5-dihydro2-[[(methoxy-carbonyl)[4(trifluorometoxy)phenyl]amino]-carbonyl]indeno[1,2-e][1,3,4]oxadiazine-4a-(3H)-carboxylate; lambda-cyhalothrin, [1,α(S*),3α(Z)]-(±)-cyano-(3-phenoxyphenyl)methyl-3-(2-chloro-3,3,3-tifluoro-1-propenyl)-2,2-dimethylcyclopropanecarboxylate; prohexadione calcium, calcium 3-oxido-5-oxo-4-propionylcyclohex-3-enecarboxylate; pyraclostrobin, methyl ester of [2-[[[1-(4-chlorophenyl)-1H-pyrazol-3yl]oxy]methyl]phenyl]methoxy-, carbamic acid; sethoxydim; tebuconazole, α-[2-(4-chlorophenyl)ethyl]-α-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol; broadleaf signalgrass, Brachiaria platyphylla (Griseb). Nash #3 BRAPP; large crabgrass, Digitaria sanguinalis (L.) Scop. # DIGSA. Additional index words: Pesticide compatibility, pesticide interaction. Abbreviations: PGR, plant growth regulator; UAN, urea ammonium nitrate.

A Modified Pool Design for Collecting Adult Mole Crickets (Orthoptera: Gryllotalpidae)

Mole crickets are one of the most damaging groups of turf and pasture grass pests found in the southeastern U.S. The need to collect mole crickets for use in laboratory studies and the advantages of monitoring adult flight for the timing of insecticide applications initiated the search for effective methods for monitoring flight activity. Ulagaraj and Walker (1973) determined that mole crickets would recognize and fly to stations that utilized electronic reproductions of the male calling song. Basic requirements for developing mole cricket calling traps were outlined by Ulagaraj (1975) and Ulagaraj and Walker (1973, 1975). The three main components of these early traps included a sound source, catching device, and power controller (Walker 1982). The sound sources, which were once tape-recorded songs of the crickets, now consist of an electronic caller that synthesizes the mole cricket song, similar to that developed by Walker (1982). Over time, the electronic callers have improved so that an external controller is no longer necessary to establish the on/off periods. Since the late 1980s, photocells that detect darkness and automatically turn on the callers at sundown have been in use rather than manual controllers (Walker 1996). In this design, originally developed by Bernie Mans for the University of Florida, the callers are also outfitted with a timer that resets the photocell after a specified time (Walker 1996), in our case two h. This allows for the production of sound during the first couple of h after sunset, a time period when most female mole crickets fly (Ulagaraj 1976). We, too, use the Mans design, and emitters were built for us by Precision Technologies Co. (Raleigh, NC). Various designs for the catching devices have been utilized including funnels or pans constructed from galvanized sheet metal that direct captured mole crickets into buckets of moist sand, and also into water-filled wading pools covered with coarse netting to prevent predation (Walker 1982). Although some of these earlier sheet metal traps have now been in use at some Florida locations for over 20 years (Frank 2001), they are expensive and not easily transported. A similar funnel design that uses lightweight fiberglass instead of sheet metal was first constructed in 1989 by Parkman and Frank (1993) to inoculate adult mole crickets with Steinernema scapterisci Nguyen Smart. This modification is less expensive to construct than the sheet metal design, but still has some disadvantages. For our laboratory and greenhouse studies at North Carolina State University, it has been necessary to collect large numbers of adult mole crickets. Unfortunately, frequent collection of crickets from calling traps is problematic, if not impossible, due to the long distances between sites. Funnel traps have been used successfully in the past, but require semi-permanent establishment at a site, something that is often difficult to accomplish on golf courses (which constitute the majority of our research sites). The funnels are also difficult to handle and transport, subject to damage during coastal storms, time-consuming to assemble, and expose the crickets to overcrowded conditions in the collection buckets. Wading pools filled with water were tested in the spring of 2002 and found to be ineffective because the crickets are only able to float for 12-24 h (Walker 1982), and frequent checking of the traps was not possible. For our research purposes, we needed a design that was inexpensive, quick and easy to assemble, temporary at each site, and able to maintain the live crickets for up to a week between visits. A modified design of the wading pools that met all of our requirements was developed in 2003. Instead of one wading pool (General Foam Plastics Corp., Norfolk, VA), two are used, one suspended above the other by four wooden, evenly distributed spacers that prevent excessive sagging of the top pool. The two pools are secured to one another by inserting a bolt (with washer) through the top pool, wooden spacer, bottom pool and then fastening all components with a nut (Fig. IA). All metal pieces were sprayed with WD-40? spray (San Diego, CA) to prevent rusting and allow for easy disassembly. The top wading pool has ten to twelve holes that are 135 mm in diameter cut into it, which allows the crickets to fall through into the bottom pool as they land and walk in the pool (Fig. iB). Instead of filling the bottom pool with water, it is filled with moist sand (Fig. IC). Because sand is used, the mole crickets are in their natural habitat when they fall through the hole in the top pool and stay healthy until retrieved. The bottom of the top pool does not touch the sand layer so it is not possible for many crickets to fly back out through the holes. The cut out holes allow for rain to moisten the sand layer, and drainage holes drilled in the bottom pool prevent flooding. The electronic caller speakers are placed on wooden boards that are centered over the top pool (Fig. 1D).

Hunting billbug (Coleoptera: Curculionidae) life cycle and damaging life stage in North Carolina, with notes on other billbug species abundance.

ABSTRACT In the southeastern United States, hunting billbug, Sphenophorus venatus vestitus Chittenden, adults are often observed in turfgrass, but our knowledge of their biology and ecology is limited. Field surveys and experiments were conducted to determine the species composition, life cycle, damaging life stage, and distribution of billbugs within the soil profile in turfgrass in North Carolina. Linear pitfall trapping revealed six species of billbug, with the hunting billbug making up 99.7% of all beetles collected. Data collected from turf plus soil sampling suggest that hunting billbugs have two overlapping generations per year in North Carolina and that they overwinter as both adults and larvae. Field experiments provided evidence that adult hunting billbugs are capable of damaging warm season turfgrasses.