Onion Maggot Management in New York, Michigan, and Wisconsin

The onion maggot (OM) continues to threaten commercial onion production in New York (ca. 12,000 acres), Michigan (ca. 8,000 acres), and Wisconsin (ca. 2,000 acres). In these states, onions are intensively grown on high organic (muck) soils. Because onion production is specialized and costly, many growers concentrate primarily on the one crop, resulting in minimal rotations to other plant species. This practice invariably increases onion maggot pressure, since this insect usually completes three generations per growing season; and has only one major commercial host in the U.S. Immature stages of the OM dwell within or just outside of underground portions of the onion plant. A system where onions are grown either continuously or in close proximity to last year's plantings must rely heavily upon effective soil chemicals applied at seeding to control the larval stages. In addition, sprays are often applied in an attempt to control the adult fly stage. However, sprays directed at flies cannot be relied upon. This is because flies move in and out of onion fields almost continuously. It has been estimated that a single application of short-lived insecticide will contact only a small percentage of the total onion fly population

Emergence Patterns of the Seedcorn Maggot, Delia platura (Diptera: Anthomyiidae)

Time of emergence of seedcorn maggot (SCM), Delia platura (Meigen), adults that developed from eggs laid in field plots from May through October 1981, was determined during 1981, 1982, and 1983. Some SCM that developed from eggs laid as early as May 1981, overwintered, and the proportion of SCM overwintering increased when eggs were laid June to October. Adults emerged from overwintered pupae from April through October 1982, and in May and June 1983. Adults of the closely related bean seed maggot (BSM), D. florilega (Zetterstedt), also emerged in the plots, but in smaller numbers than SCM. BSM males emerged in 1981 only in plots planted during May 198

An Improved Screen Cone Trap for Monitoring Activity of Flying Insects

The traps, as originally described, are difficult to build because the components are soldered together, and the traps must be replaced after three to four summers' use because of rusting. We report here a modified version of the trap that is easier to build, more durable, and more versatile

Development Rates for the Seed Maggots Delia platura and D. florilega (Diptera: Anthomyiidae)

Duration of immature stages of seedcorn maggots (SCM), Delia platura (Meigen), and bean seed maggots (BSM), D. florilega(Zetterstedt), was determined at eight constant temperatures from 5 to 40°C. No SCM or BSM survived to second instar at either 5 or 40°C. No BSM survived to the adult stage at 35°C. Duration of immature stages varied from 240 days at 10°C to 17 days at 35°C. A computer model developed using the SCM development rate data closely simulated SCM development in the field during the growing seaso

Development Rates for the Seed Maggots \u3ci\u3eDelia platura\u3c/i\u3e and \u3ci\u3eD. jlorilega\u3c/i\u3e (Diptera: Anthomyiidae)

Duration of immature stages of seedcorn maggots (SCM), Delia platura (Meigen), and bean seed maggots (BSM), D. florilega (Zetterstedt), was determined at eight constant temperatures from 5 to 40°C. No SCM or BSM survived to second instar at either 5 or 40°C. No BSM survived to the adult stage at 35°C. Duration of immature stages varied from 240 days at 10°C to 17 days at 35°C. A computer model developed using the SCM development rate data closely simulated SCM development in the field during the growing season

Emergence Patterns of Delia radicum (Diptera: Anthomyiidae) Populations from North Carolina and New York

Cabbage maggot, Delia radicum (L.), populations from North Carolina (Fletcher and Scaly Mountain) and New York (Geneva and Highland) were surveyed to detect differences in the emergence pattern of flies from overwintered pupae. Populations from all locations consisted of different proportions of early- and later-emerging individuals. However, populations from New York consisted predominately of early-emerging individuals (≥90%), whereas populations from North Carolina were composed of a higher percentage of later-emerging individuals. Emergence patterns of F1 progeny from crosses between early- and later-emerging flies from Scaly Mountain demonstrated that emergence traits were genetically controlled. D. radicum phenology studies in North Carolina suggested that temporal isolation of the two types was halted by an extended period of aestivation during the summer months, which subsequently allowed the two populations to interbreed during the autumn months. The relative proportion of early:late emergers appears to be unstable over time, which may be due to differential mortality factors operating when populations are temporally isolated or due to dominance or recessive factors governing earliness or lateness, or bot

Variations in Flight Patterns of European Corn Borer (Lepidoptera: Pyralidae) in New York

Seasonal flights of Ostrinia nubilalis (Hübner) were monitored in 1981, using blacklight traps in 28 locations in central and western New York state. Calendar date of peak catch and heat unit accumulations indicated the presence of both univoltine and bivoltine biotypes, although before this study, only the latter was assumed to be present in these regions. Both biotypes were evident at 16 of the 28 trapping sites. Trap catches during the last 5 years of a 15-year study (1967-1981), at a fixed location near Geneva, N. Y., indicated the recurrence of a univoltine population that had last been noted in this region before 1964. Losses due to larval contamination of processed snap beans are reported for 1979 and 1980. Growers of susceptible crops must be aware of local flights and the potential for shifts in peak moth emergence before insecticides are applie

Gene Flow Among Three Races of European Corn Borers (Lepidoptera: Pyralidae) in New York State

In New York state, there are three races of European corn borer moths, which are characterized principally by differences in voltinism and the sex pheromone communication system. One race is bivoltine, with females producing and males responding to a 99:1 E/Z isomeric ratio of ∆11-14:0Ac's as the sex pheromone. Two races, one univoltine and one bivoltine, produce and respond to a 3:97 E/Z blend of ∆11-14:OAc's. The races are referred to as BE, UZ, and BZ to denote these differences. Analyses by gas chromatography of field-collected females indicate that there is significant hybridization between the Z and E races when in sympatry, with hybrid females producing a 68:32 ratio of E/Z11-14:OAc. Gene flow among the races was investigated using differences in triose phosphate isomerase (TPI) allozyme frequencies of moths from sites sampled across the state. The fixed nature of the Tpi-1 allele in the BE race and increases in the Tpi-1 allele frequencies in UZ populations in sympatry with the BE race support the hypothesis that gene flow following hybridization is unidirectional from BE populations into the Z populations. In addition, the TPI genotypes of the 10 hybrid females analyzed were consistent with hybridization occurring by E males mating with Z female

Coping concordance in couples

Funding information National Institute of Mental Health, Grant/Award Number: MH60366Peer reviewedPostprin