Sridhar Polavarapu

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.

Pathogenicity of Heterorhabditis bacteriophora, Steinernema glaseri, and S. scarabaei (Rhabditida: Heterorhabditidae, Steinernematidae) Against 12 White Grub Species (Coleoptera: Scarabaeidae)

We compared the pathogenicity of the entomopathogenic nematodes Heterorhabditis bacteriophora, Steinernema glaseri, and S. scarabaei against third instars of 12 white grub species. The Japanese beetle (Popillia japonica) was highly susceptible to all nematode species. Oriental beetle [Exomala (=Anomala) orientalis], European chafer (Rhizotrogus majalis), Asiatic garden beetle (Maladera castanea), and the May/June beetles Phyllophaga crinita, Ph. congrua, and Ph. (Subgenus Phytalus) georgiana were highly susceptible to S. scarabaei but had mediocre to low susceptibility to H. bacteriophora and S. glaseri. The black turfgrass ataenius (Ataenius spretulus) was very susceptible to H. bacteriophora but had mediocre susceptibility to S. glaseri and S. scarabaei. Northern (Cyclocephala borealis) and southern masked chafer (C. lurida) had mediocre and southwestern masked chafer (C. pasadenae) and green June beetle (Cotinis nitida) had low susceptibility to all nematode species.

Effectiveness of Thiamethoxam-Coated Spheres Against Blueberry Maggot Flies (Diptera: Tephritidae)

Abstract Studies were conducted to evaluate the mortality of blueberry maggot, Rhagoletis mendax Curran, flies exposed to thiamethoxam- and imidacloprid-coated biodegradable (8-cm-diameter) red spheres, under both laboratory and field conditions. Laboratory studies with spheres coated with 0.1–2.0% (AI) of thiamethoxam indicated that they are effective against R. mendax; however, no dose-dependent response was observed. Studies on the effect of visitation time on thiamethoxam-coated spheres showed a decrease in R. mendax mortality as the duration of visitation time decreased from 60 to 10 s. Under field conditions, significantly more flies were captured on Plexiglas panes below the 2% (AI) thiamethoxam-coated spheres when compared with similar panes below untreated spheres. In field evaluations of thiamethoxam- and imidacloprid-coated spheres, imidacloprid-coated spheres (2.0% [AI]) were found to be significantly more effective than thiamethoxam-coated spheres (0.5–4.0% [AI]). Field trials to characterize the levels of mortality associated with aging pesticide-coated spheres revealed that the effectiveness of treated spheres decreased with increasing age of sphere, and this reduction in effectiveness is greater in thiamethoxam-coated spheres than in imidacloprid-coated spheres. These results provide comparative data on the effectiveness of thiamethoxam- and imidacloprid-coated spheres and support the potential of using pesticide-treated spheres for control of blueberry maggot flies.

Potential for Mating Disruption of Sparganothis sulfureana (Lepidoptera: Tortricidae) in Cranberries

Abstract The feasibility of disrupting mating of Sparganothis fruitworm with a sprayable microencapsulated formulation of (E)-11-tetradecenyl acetate (E11–14:Ac), the major pheromone component, was evaluated in New Jersey during 1996 and 1997 seasons. In both years, application of encapsulated E11–14:Ac, at 25–187.5 g (AI)/ha, reduced the incidence of mating of virgin females placed in treated plots relative to those placed in control plots. Pheromone trap catches were lower in pheromone treated plots, indicating that fewer male moths were able to locate the traps in treated plots. Larval density and fruit damage were significantly lower in plots treated with 62.5, 125, or 187.5 g (AI)/ha of pheromone than in the untreated control. Air and foliage samples were collected to determine the air titers and foliage residuals of E11–14:Ac throughout the adult flight during 1996 and 1997. E11–14:Ac levels in air and foliage samples, declined sharply one wk after the pheromone application. However, detectable levels of E11–14:Ac were present in both air and foliage samples throughout the 3- to 4-wk period after the pheromone application. Multiple applications of pheromone at lower rates may be more effective in maintaining pheromone levels than a single dose at higher rates. These results suggest that mating disruption is a promising strategy to manage Sparganothis fruitworm in cranberries.

Disruption of Sexual Communication of Oriental Beetles (Coleoptera: Scarabaeidae) with a Microencapsulated Formulation of Sex Pheromone Components in Blueberries and Ornamental Nurseries

Abstract The feasibility of disrupting sexual communication in oriental beetle, Exomala orientalis (Waterhouse) with a microencapsulated sprayable formulation of (Z)- and (E)-7-tetradecen-2-one, the major and minor pheromone components, respectively, was evaluated in blueberries and ornamental nurseries during 1998 and 1999 seasons in southern New Jersey. In 1998, pheromone-baited traps captured significantly fewer male beetles in blueberries, treated with a 9:1 blend of (Z)- and (E)-7-tetradecen-2-one at 100 g (AI)/ha of the major component, or in nurseries treated with (Z)-7-tetradecen-2-one alone at the same rate, compared with trap captures in untreated control plots. The percentage of reduction in trap captures (disruption index) in plots treated with the blend in blueberries was comparable to reductions in trap captures in nurseries (97 versus 92%) treated with the major component alone. During 1999, pheromone trap captures in blueberry and nursery plots treated with a 93:7 blend of (Z)- and (E)-7-tetradecen-2-one at 37.5 g (AI)/ha of the major component were on an average 92 and 82% lower compared with trap captures in untreated control plots, respectively. Significantly fewer tethered virgin female oriental beetles were found in copula/contact with males in treated blueberry fields relative to those deployed in untreated control plots. These results suggest that communication disruption is a promising strategy to manage oriental beetle populations in blueberries and ornamental nurseries. This is the first study to document the feasibility of disrupting sexual communication in a soil-dwelling coleopteran with applications of sex pheromone components to the soil.

Feeding and Survivorship of Blueberry Maggot Flies (Diptera: Tephritidae) on Protein Baits Incorporated with Insecticides

Abstract Laboratory feeding trials evaluated fly survivorship on six insecticides (acetamiprid, clothianidin, deltamethrin, fipronil, imidacloprid, and spinosad) incorporated at 4, 40, and 400 ppm in protein baits. Higher concentrations of insecticides resulted in increased fly mortality. At all concentrations of insecticides in baits, except those on deltamethrin, there was a significantly higher mortality 4 d after the initial feeding, compared with flies that fed on a control bait. The presence of clothianidin or imidacloprid in baits led to significantly less feeding compared with a control bait without insecticide. There were no feeding deterrent effects of bait containing either fipronil or spinosad compared with a control bait without insecticide. Exposure of flies to fresh bait containing 40 ppm of acetamiprid, clothianidin, or imidacloprid, resulted in significantly more flies becoming knocked down than the control. Baits containing 40 ppm of fipronil or spinosad resulted in higher levels of fly mortality than baits containing either neonicotinoids (acetamiprid, clothianidin, or imidacloprid) or no insecticide for trials with fresh and 1-d-old bait with unlimited exposure. At the rates tested baits containing deltamethrin resulted in no fly knockdown and always had the lowest mortality of any insecticide treatment. The tradeoffs between insecticides capable of knockdown and mortality are discussed as they relate to management of R. mendax.

Comparative Effectiveness of Different Insecticides for Organic Management of Blueberry Maggot (Diptera: Tephritidae)

Abstract Laboratory and field assays using insecticides for organic pest management were conducted on the blueberry maggot, Rhagoletis mendax Curran. Topical exposure of flies to spinosad (Entrust), pyrethrum (PyGanic 1.4 EC), azadirachtin (Aza-Direct), and phosmet (Imidan 70-W) resulted in significantly higher mortality compared with the water control after 2 and 24 h. After 24 h, there were no significant differences in fly mortality among treatments of Entrust, PyGanic, or Imidan, whereas fly mortality to Aza-Direct was significantly lower. Another laboratory assay evaluated mortality of flies after residual exposure to these insecticides on leaves, after 24 and 48 h. In this assay, there were no significant differences in fly mortality after 48 h among treatments of PyGanic, Aza-Direct, and the water control, whereas significantly higher fly mortality resulted from exposure to Entrust and Imidan. A repellency assay found no measurable effects of Aza-Direct. Large-scale field trials found no treatment effect for number of adults of the blueberry maggot captured in sticky traps; however, there were significantly lower levels of fruit-infesting larvae in treated plots compared with the untreated control. Spinosad bait (GF-120 NF Naturalyte Fruit Fly Bait), Entrust, and PyGanic were not different from imidacloprid (Provado 1.6 F). However, there was a significantly higher infestation in the plot treated with azadirachtin (Agroneem) compared with Provado. Overall, the insecticides evaluated in these trials showed good ability to control blueberry maggot, suggesting that they can be incorporated in a blueberry maggot management program under organic standards.

Diapause Development in the Blueberry Maggot Rhagoletis mendax (Diptera: Tephritidae)

Abstract Pupal diapause in the blueberry maggot was studied to characterize the relationship between temperature and development during different phases of diapause and determine the traits responsible for the late adult emergence period in some populations present in blueberry fields in southern New Jersey. Pupae in the refractory phase of diapause were exposed to 1, 4, or 7°C for 45, 90, or 135 d, and in a separate experiment, to 11 or 15°C for similar periods of time, to determine temperature thresholds and rates of diapause development at constant temperature. Results showed that pupae took much longer to reach the activated phase of diapause when exposed to 1°C than 4 or 7°C and were able to reach the activated phase when exposed to up to 15°C. In the range of 4–15°C, diapause development was largely independent from temperature. Pupae in the activated phase of diapause were exposed to 7, 15, 20, 25, 30, 25:35 (12:12 h), and 35°C for 10 d. There was a linear increase in the development rate in the range of 7–30°C, and the development rate was similar at 30, 25:35 (12:12 h), and 35°C. The proportion of pupae reaching the activated phase of diapause from August to February in a normal early population and from October to February in a late population was compared by keeping pupae in the refractory phase outdoors in a screenhouse and bringing samples to 20°C monthly. Data showed that pupae of both early and late populations reached the activated phase from October to January. The duration of the activated phase of diapause in pupae of early and late populations kept at 20°C after exposure to cold was compared by measuring changes in their respiration rates. Results showed that the activated phase lasted 10–20 d in the early population versus 60–70 d in the late population. In the blueberry maggot, and possibly in other Rhagoletis species, adaptation of the adult emergence period to the fruiting period of different host plants seems to be mediated by changes in the duration of the activated phase of diapause.

Mating Disruption of Oriental Beetle (Coleoptera: Scarabaeidae) in Turfgrass Using Microencapsulated Formulations of Sex Pheromone Components

Abstract The feasibility of mating disruption in the oriental beetle, Anomala orientalis Waterhouse, with microencapsulated sprayable formulations of (Z)-7-tetradecen-2-one, the major sex pheromone component, was evaluated in turfgrass areas. The effect of the applications was measured by monitoring male A. orientalis captures in pheromone-baited traps throughout the flight period and estimating A. orientalis larval densities in September in soil/sod samples. Trap captures were 90–100% lower in the treated areas during the first 7–10 d after treatment, but started to increase thereafter. Therefore, applications were repeated after 14 d in most treatments. The formulation tested in 2002 and 2003 reduced trap captures by 87–88% with two applications of each 12.5 or 50 g pheromone/ha but only by 74% by a single application of 75 g pheromone/ha. Reductions of A. orientalis larval populations by 68–74% were not significant because of very high variability of larval densities in the nontreated areas. Two different formulations tested in 2004 were less effective. Significant amounts of the pheromone remained on grass foliage after application, but 51 and 73% of this residue were washed off the foliage with 3.2- and 6.4-mm post-treatment irrigation, respectively. Shoes walked at 1 day after treatment through pheromone-treated areas were sufficiently contaminated with pheromone to attract high numbers of A. orientalis males in nontreated areas. Mating disruption is a promising strategy for A. orientalis management in turfgrass. However, more persistent formulations need to be developed that have a lower potential to contaminate shoes and other clothing articles with pheromone.

Phenology and infestation patterns of plum curculio (Coleoptera: Curculionidae) on four highbush blueberry cultivars.

Abstract The plum curculio, Conotrachelus nenuphar (Herbst), is a well known pest in apple and peach orchards, but it also is capable of having an economic impact in highbush blueberries. Host phenology and plum curculio oviposition patterns were determined on four highbush blueberry cultivars differing in fruit maturation period. Numbers of oviposition scars were higher on early- (‘Weymouth’) and mid-season (‘Duke’ and ‘Bluecrop’) blueberries than on late-season ‘Elliott’ in 2001, 2002, and 2003. In 2002, eggs were first present on the three earliest cultivars 21 d before those on ‘Elliott’, whereas eggs were found on ‘Elliott’ >40 d after the last sample with eggs for the other three cultivars. The pattern of host phenology and infestation levels suggested that plum curculio oviposition synchronizes well with the availability of suitable fruit for oviposition on early and mid-season cultivars compared with a late-season cultivar of highbush blueberries. The implications of a transition to use of reduced-risk insecticides are discussed in relation to plum curculio management.