Delia Antiqua Research Articles

Comparison of the circadian eclosion rhythm between non-diapause and diapause pupae in the onion fly, Delia antiqua

The influence of pupal diapause on adult eclosion rhythm of Delia antiqua was investigated. When non-diapause and diapause pupae were exposed to various photoperiods at 15, 20 and 25 °C, both of them emerged as adults close to the light-on time, but the phase of eclosion varied with photoperiod and temperature. Moreover, there was a significant difference in the eclosion time between non-diapause and diapause pupae; the eclosion peak of diapause pupae was earlier than that of non-diapause pupae. When non-diapause and diapause pupae were transferred to constant darkness (DD) after having experienced LD 12:12 at 15, 20 and 25 °C, both showed circadian rhythmicity in eclosion. Although the free-running period ( τ) decreased slightly as temperature increased in both non-diapause and diapause pupae, the latter tended to show shorter τ than the former. This observation suggests that the observed difference in eclosion time in LD cycles between non-diapause and diapause pupae is due to differences in τ.

Optimal Radiation Dose of Cobalt 60 to Improve the Sterile Insect Technique for Delia antiqua and Delia platura

A new improved diet, supplemented with fine sand, onion juice and distilled water, prevented diet from hardness and cracking, and resulted in a successful mass rearing of Delia antiqua (Meigen) and Delia platura (Meigen) for the larval development. Optimal dose of cobalt 60 gamma ray was 3 kilo-rad for sufficient sterilization of pupae of D. antiqua and D. platura. Mature sperms were not found in testes of the treated D. antiqua and D. platura, but well-developed sperms were observed in normal males. Release of sterile onion flies efficiently lowered the percentage of damaged garlic plants in greenhouse.

Seed Coating Technologies and Treatments for Onion: Challenges and Progress

Conventional methods to control the onion maggot or onion fly, Delia antiqua (Meigen), have relied on in-furrow applications of the toxicant pesticide, chlorpyrifos. The objective of this research was to develop an onion (Allium cepa L.) seed treatment that utilizes a new chemistry compound that is environmentally safe. Cyromazine is an insect growth regulator with a mode of action different from traditional pesticides used to control onion maggot. Cyromazine has low mammalian toxicity and is relatively nontoxic to other insects, including beneficials. High seed loading rates (50 g·kg-1 active ingredient) are required for optimal efficacy, and conventional slurry methods are inadequate to apply these high loading rates. Film coating and pelleting were performed at Cornell Univ. to apply cyromazine and a registered fungicide (a formulation of thiram and carboxin) to onion seeds. Results of field studies performed over several years revealed that stand losses due to the onion maggot ranged from ≈20% to 60%. Cyromazine applied by either film coating or pelleting decreased the loss by onion maggot from 1% to 8%, and efficacy was comparable to an in-furrow application of chlorpyrifos. Cyromazine was registered as a seed treatment and is commercially used in the northeastern and midwestern United States, where onion maggot is a serious pest. Field emergence was not negatively affected by cyromazine coated onto the seeds when onion seeds are sown in organic (muck) soils. There is other evidence, however, that cyromazine seed treatments may cause phytotoxicity to germination and seedling growth. Testing seed quality in sand or on roll towels revealed a high percentage of abnormal seedlings. Retarded root growth was observed in seeds treated with cyromazine, resulting in an increase in abnormal seedling classifications. A finely ground sphagnum peatmoss applied over the seeds in a roll towel test ameliorated the abnormal root growth symptoms, and seedlings had robust growth. Collectively, film coating and pelleting were effective delivery systems for the application of plant protectants required at time of sowing. Modification of the standard germination test was needed to accurately assess onion seed quality. Moreover, this project was successful due to a team effort of a university seed scientist and entomologists working with onion growers and industry. Future registrations on small acreage, high-value horticultural crops are envisioned to require similar multi-partner approaches. Chemical name used: N-cyclopropyl-1,3,5-triazine-2,4,6-triamine (cyromazine).

Dynamic changes in cold hardiness, high-temperature tolerance and trehalose content in the onion maggot, Delia antiqua (Diptera: Anthomyiidae), associated with the summer and winter diapause.

Changes in cold hardiness, high-temperature tolerance and trehalose content in the onion maggot, Delia antiqua (Diptera: Anthomyiidae), associated with the summer and winter diapause were investigated. Survival of summer- and winter-diapausing pupae after a 15 day exposure to −15°C was greater than 80%, while less than 5% of non-diapausing pupae survived the same treatment. Greater than 80% of winter-diapausing pupae survived −23°C for 15 days, but survival of summer-diapausing pupae at the same procedure was less than 30%. More than 75% of summer- and winter-diapausing pupae, but not non-diapausing pupae, tolerated 35°C for 15 days. Trehalose concentrations in summer- and winter-diapausing pupae were not high at the beginning of diapause (≈5 μg/mg), but increased gradually and reached 10 μg/mg in 40 days, although they were kept at relatively high temperatures of 25°C (summer diapause) or 15°C (winter diapause). Cold hardiness of pupae, however, was not proportional to their trehalose content; although trehalose concentrations in winter- and summer-diapausing pupae at day 40 (WD40 and SD40) were similar (≈10 μg/mg), cold hardiness of these pupae differed largely (WD40>SD40).

Effects of Ambient Temperature and Temperature Cycle on Locomotor Activity Rhythm in the Onion fly, Delia antiqua

Abstract The phase of locomotor activity of the onion fly, Delia antiqua, in LD12:12 advanced at a low temperature (20°C) as compared with that at a high temperature (25°C). The free-running period (τ) in constant darkness (DD) at 20°C became shorter than that at 25°C, suggesting that the phase advance of locomotor activity in LD cycles at 20°C was caused by the decrease in τ. In constant light (LL), the locomotor activity was arrhythmic at a constant temperature. In both DD and LL, the locomotor activity was entrained to a 12 hr 25°C:12 hr 20°C temperature cycle; the activity occurred in the thermophase and its peak delayed with age. However, the delay in LL was smaller than that in DD. At a cycle of 12 hr cool (20°C) light and 12 hr warm (25°C) dark, the fly showed a similar activity pattern to that in LD 12:12 at a constant temperature (20°C or 25°C); the activity occurred in the light phase. This suggests that LD cycle is a stronger zeitgeber than a temperature cycle to entrain the locomotor activity ...

Development of a simulation model for the population dynamics of the onion fly Delia antiqua in Germany*

Delia antiqua is a serious pest of many species of the genus Allium, including onions and chives. Over a period of two years (1997/1999), we have developed a model to simulate the population dynamics of D. antiqua based on an extended Leslie model. The model structure as well as the developmental functions for the different life stages of D. antiqua are presented. Using daily mean air and soil temperatures, the model calculates the population matrix for developmental stages of D. antiqua including eggs, larvae, pupae and adults. The simulation can be used to optimize the timing of control measurements against a specific life stage of D. antiqua. Flight activity can be simulated using wind speed as additional information. Simulated flight activity and the observed flight activity of D. antiqua monitored with water pan traps in three different regions of Germany in 1998 are presented and discussed. The model, which was programmed as part of the SWAT 3.5 package of programs to simulate the population dynamics of root‐fly pests in horticultural crops, will also be available via other expert systems such as PASO.

Biphasic effect of low temperature on completion of winter diapause in the onion maggot, Delia antiqua

The effect of low temperature on completion of winter diapause was investigated in the onion maggot, Delia antiqua (Diptera: Anthomyiidae). Diapause was completed under constant diapause-inducing conditions of 15°C and 12L–12D, without any exposure to lower temperature. The pupal period for 50% adult emergence was 117 days. None of the cold treatments at 5.6°C examined in the present study advanced adult emergence; on the contrary, they delayed it. Detailed analyses of the results revealed that diapause development in D. antiqua comprises two phases which differ in sensitivity to low temperature, with the phase shift occurring at around day 60 at 15°C and 12L–12D. In the first phase of diapause development, low temperature (5.6°C) had no effect on diapause development. In the latter phase, by contrast, diapause development was retarded in proportion to the duration of cold treatment.

Characteristics of summer diapause in the onion maggot, Delia antiqua (Diptera: Anthomyiidae)

Characteristics of summer diapause in the onion maggot, Delia antiqua, were clarified by laboratory experiments. Temperature was the primary factor for the induction of summer diapause in this species. The critical temperature for diapause induction was approximately 24°C, regardless of the photoperiod. At 23°C, the development of the diapausing pupae was arrested the day after pupariation, when about 7% of the total pupal development had occurred in terms of total effective temperature (degree-days). The most sensitive period for temperature with regard to diapause induction was estimated to be between pupariation and “pupation” (i.e., evagination of the head in cyclorrhaphous flies). Completion of diapause occurred at a wide range of temperatures (4–25°C): The optimal temperature was approximately 16°C, at which temperature only five days were required for diapause completion. The characteristics of summer diapause in D. antiqua are discussed in comparison with those of summer dormancy in a congener D. radicum and those of winter diapause in D. antiqua.

Effect of Dim Light on Locomotor Activity Rhythm in the Onion fly, Delia antiqua

Abstract The phase of locomotor activity of the onion fly, Delia antiqua, in L (400 lux) Ldim (1.0 lux) cycles delayed as compared with that in LD cycles. The free-running period (τ) in constant dim light (LdimLdim) was longer than that in constant darkness (DD), suggesting that the phase delay of locomotor activity in LLdim cycle was caused by the increase in τ. At LdimD 12:12 in which the light intensity of the photophase was 1.0 lux, the locomotor activity free-ran with the period shorter than 24 hr until about week 2 after eclosion but thereafter entrained to LdimD in spite of τ might become longer than 24 hr. This suggests that the flies may become more sensitive to light intensity with age.

Incidence and control of onion fly, <i>Delia antiqua</i>, at some irrigation sites in the Upper East Region of Ghana

Studies were conducted between 1994 and 1997 on the incidence, distribution, and control of the onion fly Delia antiqua in northern Ghana. Results showed that the insect is prevalent in most of the onion-growing areas and is capable of causing up to 33 per cent crop damage. It was also established that early transplanting (before mid-January) and transplanting of seedlings 6 weeks after emergence reduced D. antiqua infestation and crop damage. Neem seed powder and aqueous neem seed extract were as effective as Carbofuran for the control of the onion fly. Economic nalysis showed that the neem products were the most cost-effective and had the best returns. Ghana Jnl agric Sci. Vol.32(2) 1999: 205-211

Manipulating carabid beetle abundance alters prey removal rates in corn fields

Generalist natural enemies such as carabid beetles have the potential to maintain a variety of pests below outbreak levels in annual crops. To assess the relationship between carabid beetle abundance and field rates of prey removal, we created plots surrounded by different boundaries that selectively affected dispersal of edaphic arthropods, primarily carabids. Three treatments were established: (1) naturally occurring communities, (2) augmented communities using ingress boundaries, and (3) reduced communities using egress boundaries. Selective boundaries altered carabid communities with minimal habitat alteration and without use of insecticides. Three times during the growing season, a fixed number of onion fly pupae were placed in plots to evaluate the impact of carabid abundance on predation rates. A combination of vertebrate and invertebrate exclosures allowed us to evaluate prey removal by invertebrates alone. In comparison to the no boundary treatment, carabids increased 54.2% and decreased 83.1% in plots surrounded by ingress and egress boundaries respectively. Predation rates were positively correlated with carabid abundance (r2 = 0.70, p < 0.0001). Significantly more pupae were removed from exclosures allowing access to invertebrates alone than from total exclosures, suggesting that invertebrates represented an important group of predators. Laboratory trials tested the feeding potential of the four most abundant carabid species and showed that they readily consumed onion fly pupae, supporting our hypothesis that carabids were the main predators in field tests. This study corroborates and extends previous observations of the importance of carabid beetles as generalist predators of insect pests in agricultural fields.

Specificity of accessory gland extracts. in three Delia fly species (Diptera: Anthomyiidae)

Abstract. Extracts of testes and male accessory (paragonial) glands made from three species of Delia (onion fly {D.antiqua), seedcorn fly (D.platura), and cabbage fly (D.radicum)) were injected into conspecific virgin females. Extracts of paragonial glands, but not testes, from onion, seedcorn and cabbage fly males stimulated oviposition and suppressed mating when injected into conspecific virgin females. When extracts of paragonial glands from males of these species were injected into heterospecific virgin females, the extracts of D.antiqua and D.platura were fully cross‐reactive with respect to oviposition; interspecific injection stimulated oviposition at the level of the conspecific mated controls. Injection of D.radicum extract fully activated the D.antiqua and D.platura ovipositional response. D.antiqua extract caused mating inhibition and partial oviposition in D.radicum; that of D.platura had no effect on either oviposition or mating inhibition in D.radicum. These results suggest that D.antiqua and D.platura are more closely related to one another than either is to D.radicum, and agree with published anatomically‐based phylogenies and a genetic distance calculation based on eight enzyme loci. The occurrence of sex peptide cross‐reactivity, though asymmetrical, between D.radicum versus D.antiqua and D.platura indicates that, functionally, sex peptides have changed little during the evolution of this genus. An emerging pattern of broad cross‐reactivity within genera suggests that sex peptides are not an initiator of reproductive isolation.

Limitation of Dietary Copper and Zinc Decreases Superoxide Dismutase Activity in the Onion Fly, Delia antiqua

Larvae of the onion fly, Delia antiqua, have lower superoxide dismutase (SOD) activity when they are fed a defined synthetic diet that contains no copper or zinc. SOD activity was rapidly recovered when these larvae were fed onion bulbs. Addition of copper and zinc to the synthetic diet also led to the recovery of SOD activity. Results of an immunoblotting analysis using anti-D. antiqua CuZnSOD mouse monoclonal antibody suggest that this alteration of SOD activity is dependent on the amount of CuZnSOD.

Host-Finding and Upwind Anemotaxis by Delia antiqua (Diptera: Anthomyiidae) in Relation to Age, Ovarian Development, and Mating Status

A dual-port wind tunnel was used to test hypotheses that odor-mediated anemotaxis in the onion maggot, Delia antiqua (Meigen), to volatiles of onion, Allium cepa L., is affected by differences in age, sex, mated status, and ovarian development. In the absence of odor and air movement, adults of both sexes dispersed randomly in the wind tunnel. They displayed significant, albeit weak (≈15%), anemotactic (upwind) response to air movement at 8.0 cm/s. In 12 h comparisons of virgin females tested at 2, 4, 6, 8, and 10 d of age with gravid, mated females (10–12 d), anemotactic and discriminatory responses to onion odor of females aged 4–10 d were comparable (≈30%), but were consistently lower than the responses of gravid, mated females (≈45%). Male upwind response to host odor increased linearly with age over 10 d. When 10-d-old males were tested together with females in the wind tunnel, however, significantly fewer males were attracted to onion than when females were absent. Ten-day-old protein-deprived virgin and mated females (both previtellogenic) responded to onion odor in a similar manner as did gravid, mated females. The response of mated, 10-d-old previtellogenic females was lower than that of gravid, mated females. We conclude that upwind response by D. antiqua to host odor is independent of female ovarian development or mated status. Such a response would serve to draw females to their oviposition sites and may assist males in locating sites where females are likely to arrive.

Effects of photoperiod and aging on locomotor activity rhythms in the onion fly, Delia antiqua

At photoperiods longer than 8 h per 24 h, adults of the day-active onion fly Delia antiqua showed a major peak of locomotor activity in the late photophase and also bursts of activity induced by lights-on or lights-off. At shorter photoperiods the activity peaks fused. After transfer from long photoperiods to constant darkness (DD), the rhythm free-ran, but only the major peak persisted. This suggests that only the major peak is controlled by the circadian pacemaker. At long photoperiods, the daily phase of the major peak occurred progressively later with age. As a result, the activity at short photoperiods often shifted from photophase to scotophase in old flies. The free-running period ( τ) also changed with age; τ was shorter than 24 h until 14–20 days after eclosion and thereafter became longer, but a few individuals repeated changes in τ. The phase delay of locomotor activity with age in D. antiqua would be attributable to the increase in τ.

Foliar form, colour and surface characteristics influence oviposition behaviour of the carrot fly

AbstractVarious leaf models made of paper were presented to carrot flies, Psila rosae (F.) (Diptera: Psilidae) in choice assays to investigate the effect of non‐chemical plant traits on oviposition behaviour. The surrogate leaves differed in colour, shape, surface coating, size and stem length. In the presence of host‐plant extracts, physical factors strongly influenced oviposition. Green, yellow and orange three‐dimensional models similar in shape to host‐plant leaves (pinnately or ternately compound or dissected) and with a thin cover of paraffin wax were most acceptable to the females. Egg‐laying was not affected by leaf size, but was negatively correlated with stem length. The results obtained by testing models with simple leaf silhouettes were confirmed in an experiment using more lifelike imitations of real host and non‐host leaves. The findings are discussed by an extensive review of similar studies in three other phytophagous fly species (cabbage root fly, onion fly, Hessian fly).

Dietary constraints on sexual activity, mating success, and survivorship of male Delia antiqua

AbstractThe effects of protein‐deprivation on the sexual activity and reproductive fitness of male onion flies, Delia antiqua (Meigen) (Diptera: Anthomyiidae), were investigated under laboratory conditions. The percentage of males inseminating gravid females, the magnitude of ovipositional response, and the total numbers of eggs deposited in 1:1 or 1:10 male:female matchings over two days was unaffected by deprivation of dietary protein. The LT50's (median survival time) for solitary males provided proteinaceous, sucrose, or water diets were 38.0, 25.8, and 6.0 days, respectively. Yet independent of diet effects, males lost 50% of their wing tissue by fragmentation after 26 days, suggesting that wing condition is more important in determining male reproductive fitness than longetivity. Male mating frequency in single pairings with previtellogenic females deprived of proteinaceous diet for ten days was similar to that of gravid, protein‐fed females. In no‐choice and choice mating bioassays at a 10:1 female:male ratio, however, males inseminated significantly fewer previtellogenic than gravid females over 24 h. Despite evidence for male autogeny, removal of exogenous protein resources in the Allium agroecosystem may have important effects on the reproductive competency and fecundity of D. antiqua.

Variation in Allium spp. Damage by Onion Maggot

Nearly 350 germplasm accessions representing 25 Allium species were evaluated for damage by onion maggot (OM) [Delia antiqua (Meigen)] in field experiments in 1989. In 1990, 188 additional accessions and breeding lines were evaluated, and 36 entries from the 1989 evaluation were re-evaluated. In both years, there were no significant differences in OM damage to seedlings among accessions within the species tested. However, differences among species were highly significant. Allium cepa L. (bulb onion) seedlings had consistently high OM damage. Species with significantly less seedling damage than A. cepa included: A. altaicum Pall., A. angulosum L., A. galanthum Kar. &amp; Kir., A. pskemense B. Fedtsch., A. scorodoprasum L., A. ampeloprasum L. (leek), A. fistulosum L. (bunching onion), A. schoenoprasum L. (chive), and A. tuberosum Rottl. ex Spr. (garlic chive). Some species sustaining minimal damage as seedlings were nonetheless heavily damaged as mature plants by a later generation of OM. Allium cepa cultivars that were well-adapted to local conditions were heavily damaged as seedlings, but their bulbs were less damaged than those of poorly adapted A. cepa germplasm. Allium ampeloprasum seedlings and mature plants sustained low injury throughout both growing seasons.

Integrated Management of the Onion Maggot (Diptera: Anthomyiidae)

In the absence of crop rotation, onion maggot, Delia antiqua (Meigen), control was inadequate (<10% plant loss) in field trials within a commercial onion production area when susceptible and potentially resistant onion genotypes were treated with chlorpyrifos at planting. However, when treatments were applied to the same entries in an area that had been rotated completely out of onion production the previous year, exceptional onion maggot damage reduction was noted (<2% plant losses). In the nonrotated area, one genotype (PI 432715) had reduced onion maggot damage compared with that of susceptible onion cultivars when treated with half rates of chlorpyrifos. Rotation of complete production areas can provide effective onion maggot control. When rotation is not possible, integration of plant resistance and judicious application of insecticides may be appropriate.

Courtship behavior and discrimination between potential mates by maleDelia antiqua (Diptera: Anthomyiidae)

The repertoire of courtship behaviors of male onion maggots,Delia antiqua (Meigen), in a laboratory bioassay chamber, was analyzed by direct observation and by video recordings, in conjunction with a multichannel event recorder. Seven courtship behaviors were categorized: inspection from the substrate, aerial inspection, contact from the substrate, contact from the air, genital alignment, copulation, and male-male interaction. The frequency distribution of copulation bouts was best described by a Poisson distribution; peak mating activity occurred about 1 h into the bioassay. The duration in copulo, however, was extremely variable. On average, males spent ≈30 sin copulo (n=183); 50 s. The ability of males to discriminate between sexes, sexually immature and mature females, and between females ofD. antiqua and the cabbage maggot,Delia radicum (L.), was most pronounced in the elements of genital alignment and attempted copulation. The courtship and mating behavior inD. antiqua is consistent with a sequence that relies initially primarily on indiscriminate visual recognition of a potential mate, followed by species-and sex-specific semiochemical recognition upon contact.