Moth Emergence Research Articles

Oviposition site selection in Cactoblastis cactorum (Lepidoptera): constraints and compromises.

Oviposition by Cactoblastis cactorum on Opuntia ficus-indica and O. aurantiaca was assessed from the positioning of egg sticks on plants in the field. The number of egg sticks laid on O. ficus-indica plants was affected by: (1) plant size; (2) moth emergence near the plant; (3) cladode condition; and (4) plant conspicuousness. These factors contributed towards the clumping of egg sticks on plants. There was no apparent oviposition preference for one of the two host plant species despite the fact that egg predation was higher and fecundity lower on O. aurantiaca. The selection of a site for oviposition on the host plants was influenced by: (1) cladode condition; (2) height above ground; and (3) shelter from wind during oviposition. Succulent cladodes were the favoured sites for oviposition. The evidence suggests that in C. cactorum, oviposition site selection is largely the net result of a compromise between oviposition behaviour selected for increasing the probability of juvenile survival and oviposition behaviour selected for increasing the probability of laying the full complement of eggs. In addition, environmental and physiological factors such as wind and wing-loading, are thought to place constraints on the range of sites available for oviposition.

Nocturnal behaviour of adults of Heliothis armigera (Hübner) (Lepidoptera: Noctuidae) in the Sudan Gezira and pest control implications

AbstractField and cage observations were made on Heliothis armigera (Hübner) in the Sudan Gezira to quantify nocturnal patterns of moth emergence, copulation and oviposition and the ages at which copulation and egg-laying occur. The flight activity pattern of males, virgins and inseminated females was assessed for crops with scarce or abundant sources of honeydew or nectar. A pronounced redistribution of moths between crops during the peak flight activity period (18.15-19.30 h) was demonstrated and measured, with the net exchange being approximately balanced. The direction of this movement was dependent upon the attractiveness of crops for feeding or oviposition. Male and female moths developing from larvae reared on groundnuts had significantly shorter lifespans when fed only water and less fat-body at emergence than moths developing from larvae reared on sorghum. When offered sugar solution, lifespans were significantly greater and differences in the lifespan of moths from groundnuts or sorghum were no longer evident. Adult feeding appears to compensate for any deficiencies associated with a larval diet of groundnut. Feeding was important for adult survival; there was a strong attraction of moths to crops with plentiful honeydew or nectar. A descriptive behavioural model is presented for the first half of adult life, until peak oviposition, and the uses of this model for pest management are discussed.

Development and survival ofMythimna separata (Wlk.) on some host plants during winter at Hisar

Survival and post embryonic development of the oriental armyworm,Mythimna separata (Wlk.) was studied on 5 host plants, viz sorghum, maize, sugarcane, Johnson grass and napier grass during winter months (15 November to 7 March) under laboratory conditions. Variations in different parameters like larval survival (10·3–60·3%), size of larvae (7·33–29·67 mm), larval weight (25·5–493·1 mg for 26 days old larva), size of pupa (15·0–16·49 mm), pupal weight (184·9–249·5 mg for 2–4 days old pupa), pupation (3·3–38·9%), developmental period (74·8–109·8 days) and moth emergence (3·4–50·0%) were significant on different foods. Low temperature and humidity conditions during experimental period resulted in complete mortality of female pupae reared on napier grass, Johnson grass and maize whereas in case of males 60–100% moths were crippled winged. However, adults emerged on sorghum and sugarcane foods were normal except 28·7% males in sorghum were crippled. Total growth index was also higher on sugarcane (0·45) and sorghum (0·24) indicating their suitability in carrying over of winter pest population.

ASSESSMENT OF A SEX-ATTRACTANT TRAP FOR MONITORING THE SPOTTED TENTIFORM LEAFMINER, PHYLLONORYCTER BLANCARDELLA (FABR.) (LEPIDOPTERA: GRACILLARIIDAE): RELATIONSHIP BETWEEN MALE AND FEMALE EMERGENCE AND BETWEEN TRAP CATCHES AND EMERGENCE

AbstractThe temporal relationship between male and female emergence and the relationship between attractant-baited trap catches and emergence of the spotted tentiform leafminer, Phyllonorycter blancardella (Fabr.), were studied in commercial apple orchards in Norfolk County, Ontario, during 1983 and 1984. The onset and progression of male and female emergence was highly synchronized during each of the three-yearly activity periods. The traps were a sensitive indicator of the onset of the spring-emergence period. However, peaks in the numbers of moths trapped did not occur at times of peak moth emergence and changes in the size of trap catches were not a reliable indicator of changes in the rate of moth emergence. During the spring-emergence period, peaks in trap catch were associated with relatively high daily air temperatures.

Pink Bollworm (Lepidoptera: Gelechiidae) Egg Hatch, Larval Success, and Pupal and Adult Survival on Okra- and Normal-leaf Cotton1

Previous observations that okra-leaf cotton, Gossypium hirsutum L., sustained less seed damage caused by pink bollworm (PBW), Pectinophora gossypiella (Saunders), than normal-leaf cotton prompted a search for the cause of the reduced damage. In one series of experiments, bolls of ‘Stoneville 7A’ okra-leaf and ‘Stoneville 7A’ normal-leaf cotton were infested artificially with PBW eggs or first instars and boll temperatures were monitored. Egg mortality was not significantly different, but number of PBW entrance holes was reduced ca. 13% in bolls of okra-leaf cotton. Boll temperatures generally were slightly higher in okra-leaf cotton but differences were not great enough to explain the difference in number of entrance holes or insects per boll. In a second series of experiments, fourth instars were placed either in boxes of soil under plant canopies and collected later, or in containers placed in canopies where they were allowed to tunnel out of the containers, fall to the soil, and emerge as adults. In the soil boxes, no significant differences were found in temperature, relative humidity or in insect survival under the normal- and okra-leaf canopies. In the larval emergence experiment, soil temperature was significantly higher under the okra-leaf canopy than under the normal-leaf canopy but larval emergence from bolls and moth emergence from pupae were not significantly different.

Larval Survivorship of Argyrotaenia citrana (Lepidoptera: Tortricidae) Overwintering on Small Fruits in the Pacific Northwest

Immature Argyrotaenia citrana (Fernald) overwintering on red raspberry and blueberry in Oregon and southwest Washington suffered high mortality following a severe winter storm in 1983. A comparison of the population age structure before and after this storm suggested that older instars were most susceptible to low temperatures. Laboratory bioassays conducted at −5, −10, and −15°C demonstrated that laboratory-reared third instars were significantly more tolerant to subfreezing temperatures than were fifth instars. Larvae sprayed with water before exposure were significantly less tolerant than unsprayed larvae. Preconditioning larvae for 28 days with a 12:12 (L:D) photoperiod at 6° (L) and −1°C (D) increased third-instar tolerance but decreased fifth-instar tolerance to −100°C exposure. Field experiments during 1984–85 demonstrated that field-collected third instars were significantly more cold tolerant than older instars. Analysis of winter temperatures for 1978–85 suggested that winters could be classified based on number of hours below −5°C during the season. Correlation of this factor with degree-day totals from 1 January to peak pheromone trap catch of A. citrana for these years was high, indicating that winter temperatures have a significant impact on phenology of spring moth emergence.

Interpreting ultraviolet-light and fermentation trap catches of Mythimna convecta (walker) (Lepidoptera: Noctuidae) using phenological simulation

AbstractUltraviolet-light and fermentation trap catches of adults of Mythimna convecta (Walker) in Victoria, Australia, could be related to the times of various stages of larval development in oat crops by means of a day-degree accumulation model. Mated females were more attracted to fermentation than ultraviolet-light traps, and predicted oviposition times closely coincided with fermentation trap catches. The phenological model successfully mimicked the observed larval instar development in the field. Peak moth flights occurred within three periods. The first peak period (October to mid-November) usually contained mated moths which generated larval populations in maturing oat crops; in 1983, these moths probably occurred in late August. The second (mid-November to December) contained unmated females; in 1983–84, moth flights during this period could be related to the emergence of moths from crops 70–130 km north of the trap site. The third peak period (January to February) also comprised unmated moths which had usually emerged locally and were probably emigrating.

Attraction of Harrisina americana and Acoloithus falsarius Males (Lepidoptera: Zygaenidae) to (R)-(−)-2-butyl-(Z)-7-tetradecenoate1

Males of two species of Zygaenidae, the grapeleaf skeletonizer, Harrisina americana (Guerin), and Acoloithus falsarius Clemens, were attracted to ( R )-(−)-2-butyl-( Z )-7-tetradecenoate in field trapping tests. Presence of the ( S )-(+) enantiomer in racemic 2-butyl-( Z )-7-tetradecenoate appeared to reduce trap catches of males of both species. Pure ( R )-(−)-2-butyl-( Z )-7-tetradecenoate may be useful as an attractant for monitoring emergence of grapeleaf skeletonizer moths and their population cycles in grape vineyards.

Survival, Emergence, and Release of Laboratory-reared, Backcross Tobacco Budworm (Lepidoptera: Noctuidae) Pupae Shipped from Stoneville, Miss., to St. Croix, U.S. Virgin Islands

A pilot test was conducted on St. Croix, U.S. Virgin Islands, to determine the feasibility of controlling the tobacco budworm, Heliothis virescens (F.), by releasing backcross insects possessing an inherited male sterility resulting from interspecific hybridization. During 1979 and 1980, four separate releases were made and adult emergence (ca. 90%) was excellent. Moth emergence began in the early evening hours. For any particular shipment, females emerged sooner than males. After release, numbers of males trapped declined rapidly, suggesting a survival of 3–5 days and an intermating period of no more than 2 nights.

シロイチモジヨトウの生態と防除に関する研究 Ｉ 発育と温度

The beet armyworm, Spodoptera exigua (HUBNER) is well known as an important pest of various kinds of economic plants in many countries. In Japan, only a few reports on beet armyworm and its damage have been published.Recently in Kagoshima Prefecture, the beet armyworm has been observed in green onion fields, causing serious damage.The current studies on the ecology and control of the beet armyworm were initiated in 1985. The present report deals with the developmental biology of the beet armyworm in relation to temperature. In the laboratory experiments, the threshold temperatures for development and the effective thermal totals of egg, larva, pupa and egg to moth emergence were estimated to be 10.5, 15.3, 15.6 and 15.3C and 49, 162, 74 and 270 day-degrees, respectively.

Archytas marmoratus (Diptera: Tachinidae): Screened-cage Performance of Mechanically Extracted Maggots Against Larval Populations of Heliothis zea and Spodoptera frugiperda (Lepidoptera: Noctuidae) on Whorl and Early Tassel-stage Corn1

Mechanically extracted maggots of Archytas marmoratus (Townsend) were evaluated against larva populations of Spodoptera frugiperda (J. E. Smith) and Heliothis zea (Boddie) in whorl and early tassel-stage sweet corn, Zea mays L., grown within 1.8-m3 screened cages. A. marmoratus maggots applied in an aqueous carrier at 5.4, 10.9, and 21.7 per plant against late-instar S. frugiperda reduced subsequent adult emergence by 40.2, 56.6, and 66.5%, respectively. A. marmoratus maggots applied at 5.5, 12.5, and 25.0 per plant against late-instar H. zea reduced subsequent adult emergence by 56.0, 56.9, and 81.9%, respectively. Maggots applied on the soil surface at rates to 25 per 100 cm2 against larvae of S. frugiperda in search of pupation sites had no significant effect on the subsequent emergence of adult moths. Likewise, volumes of aqueous carrier at rates of 0.05–1.25 ml per plant had no effect on the performance of A. marmoratus maggots against H. zea larvae in corn.

OBSERVATIONS, MONITORING, AND CONTROL OF CLEARWING BORERS (LEPIDOPTERA: SESIIDAE) ON APPLE IN CENTRAL ONTARIO

AbstractObservations on Malus domestica (Borkh) in central Ontario between 1981 and 1984 revealed that dogwood borer (Synanthedon scitula Harris) larval feeding was primarily associated with burr knots on the above-ground portion of apple rootstocks. Trunk injuries also served as sites of entry. Monitoring with pheromones indicated moth emergence occurred from late June until early August with peak activity occurring near the middle of July. Control of the dogwood borer on apple was obtained with 2 trunk drench sprays of dimethoate, fenvalerate, permethrin plus oil, endosulfan, parathion, chlorpyrifos, or lindane when applied during the period of adult flight activity.

Large-scale Rearing of a Sterile Backcross of the Tobacco Budworm (Lepidoptera: Noctuidae)1

From 1978 to 1982, 10,265,083 pupae were reared in support of the USDA-ARS pilot test “Management of tobacco budworm with hybrid sterility.” Most pupae were shipped to the test site (St. Croix, U.S. Virgin Islands), where the sterile backcross (BC), tobacco budworm (TBW) ( Heliothis virescens [F.]) male × BC female from the intercross TBW male × H. subflexa (Guenee) female was released for suppression of the TBW population. During a span of 117 consecutive days in late 1980, 5,713,245 BC pupae were shipped to St. Croix at the rate of 48,831 pupae per day. Moth emergence from pupae after shipment was 88 ± 5%; 7 ± 7% of the adults were deformed. Interaction of laboratory-reared moths with the feral population was verified by increase of sterility in feral TBW females, increase in percentage of feral males transferring only apyrene sperm, and consequent population suppression. Facilities at Stoneville were modified for maintaining BC and TBW brood colonies as well as large-scale rearing of the BC. Consistent production of high-quality insects required implementation of rigid protocols for larval rearing, moth holding, and egg collection and infesting of diet, pupal harvesting and shipment, and sanitation. Mass production of Heliothis spp., and the TBW sterile BC, specifically, requires automated rearing procedures as well as expanded facilities if areawide population suppression of TBW on the United States mainland is attempted.

Sunflower Moth (Lepidoptera: Pyralidae): Overwintering and Dynamics of Spring Emergence in the Southern Great Plains

Diapausing prepupae of the sunflower moth, Homoeosoma electellum (Hulst), did not survive >7 consecutive days at −5°C in the laboratory. However, chilling diapausing prepupae in darkness at 0°C for up to 14 days resulted in significantly quicker pupal development and a greater survival than either chilling them for a longer period of time in darkness or holding them at a higher temperature or longer photophase. Prepupae survived winter field conditions at Bushland, Tex., to pupate successfully and produce emerging adults. Mean initial emergence for 1981–1983 occurred on Julian day 137, compared with a predicted mean initial emergence on Julian day 134 ± 12 based on 7 years of soil temperature data and a developmental threshold of 15.24°C. Computation of degree-day accumulations from soil temperature data from a depth of 10 cm from 51 locations throughout the Great Plains enabled development of a simple model for predicting mean initial emergence of the sunflower moth in areas where it survives. Data from independent field studies on sunflower moth overwintering closely fit the predictions of our model for the southern Great Plains.

Improved Oviposition and Egg Collection System for the Fall Armyworm (Lepidoptera: Noctuidae)1

An efficient oviposition and egg collection system was developed for the fall armyworm, Spodoptera frugiperda J. E. Smith), using a large cage with built-in features for moth emergence, feeding, and Oviposotion, and removal of spent and dead moths. The cage is operated continuously as pupae are added daily. Females oviposit on wax paper sheets easiy removed from and replaced within the cage. Beer, as an adult food source, is added dally to easily accessible feeding stations within the cage. Spent and dead moths are removed through a trap door in the cage bottom. Cage design, fabrication materials, construction, and servicing are discussed. A system to remove moth scales from the facility housing the adult colony also is described.

Oviposition Behavior and Temperature Effects on Egg Development of the Southern Pine Cone worm Dioryctria amatella (Lepidoptera: Pyralidae)

Peak oviposition by Dioryctria amatella (Hulst) females occurred from 5 to 7 days after moth emergence and ca. 80% of the eggs were laid during the period from 3 to 12 days after emergence. The threshold temperature for D. amatella egg development was determmed to be 11°C. The number of degree-days required for complete egg development ranged from a mean of 115.5 degree-days at 16°C to 84 degree-days at 28°C. The estimated number of degree-days required for egg hatch was 86.6.

Response of the Western Spruce Budworm, Choristoneura occidentalis (Lepidoptera: Tortricidae), to Temperature: The Stochastic Nature of Developmental Rates and Diapause Termination

The variability in the developmental rates for the embryos, larvae, and pupae of the western spruce budworm, Choristoneura occidentalis , was skewed and was well described by a gamma probability density function. At extreme temperatures, the shapes of the frequency distributions for the embryos and pupae were not unimodal, suggesting the presence of thermal biotypes. Variability increased markedly towards the temperature extremes (15 and 31°C) and was greater for female than for male larvae. The shapes of the frequency distributions for larvae terminating diapause ranged from a skewed curve for second-instar larvae held in diapause at 0°C to a negative exponential curve for larvae held at 5°C. A Monte Carlo simulation model showed that the probability of synchronous emergence of male and female moths was relatively constant (ca. 66%) over a range of average minimum/maximum temperatures. During the larval developmental period, average minimum/maximum ranged from 2.3/18.1 to 6.0/21.0°C. For the pupae developmental period, average minimum/maximum temperatures ranged from 6.0/21.0 to 1l.4/27.1°C. Above these temperatures, the probability of synchronous emergence decreased.

Steroid regulation of neuronal death in the moth nervous system

The emergence of the adult Manduca sexta moth is followed by the programmed degeneration of about 50% of the insect's abdominal interneurons and motoneurons. Neurons in implanted ganglia undergo degeneration in concert with neurons of the host, thereby indicating that a hormonal cue is important. The neuronal death follows the normal decline in the levels of the steroid hormones, ecdysteroids, that occurs at the end of metamorphosis. Manipulations that cause a precocious ecdysteroid decline result in an early death of the neurons. Also, prolongation of the ecdysteroid titer extend the life of the neurons. By properly timed steroid application it was possible to dissociate the neuronal degeneration from the behavioral events and muscle degeneration that also occur at emergence. Also the stereotyped sequence of death among identified motoneurons could be stopped at various points in the sequence by the carefully timed application of steroid. It was concluded that the signal for neuronal death was the withdrawal of ecdysteroids at the end of metamorphosis and that the death was probably a direct response of the individual neurons to the hormone withdrawal.

Effects of Soil Compaction on Bollworm (Lepidoptera: Noctuidae) Moth Emergence 1

Bollworm, Heliothis zea Boddie, moth emergence was measured from a sandy loam soil after increasing levels of soil compaction. Soil strength as measured by indentation probe resistance in kg/cm 2 was measured at successive depths under each level of compaction and related to the moth emergence pattern. Possible physical damage to pupae and the condition of the pupal chamber by the compaction process was determined by placing individual insects in cylindrical containers of soil, compacting the soil in the containers, and then excavating the pupae. Moth emergence decreased significantly with increasing soil compaction and also showed a definite relationship to the pattern of soil compaction vs. depth. Excavation of pupae from compacted soil indicated that soil compaction, rather than physical damage to the pupae, was the primary cause of reduced moth emergence.

Influence of Residual ‘Nonpareil’ Almond Mummies on Densities of the Navel Orange worm and Parasitization1

Navel orangeworm, Amyelois transitella (Walker), density on mummy almonds was significantly influenced by the numbers of mummies present in a tree, but ovipositing moths apparently did not distinguish high from low mummy abundance. Parasitization by three species of parasites significantly reduced navel orange worm moth emergence, though reduction was minimal in trees with less than five mummies. Presently established parasites would probably not have to be considered in predictions of moth emergence from such trees. However, in orchards where tree canopies intermingle, a lower tolerance of mummies may be required for minimal moth emergence.