Panolis Flammea Research Articles

Post‐spray effects of an aerial application of fenitrothion on the pine beauty moth,Panolis flammea(Denis & Schiffermüller)

Abstract Panolis flammea that had survived an aerial spraying programme of fenitrothion were compared in a series of laboratory experiments with moths that had not been within the sprayed area, to assess the effects of sub‐lethal spray application on various life history parameters. Emergence success was not significantly different between the two treatments and the sex ratio in both cases approximated 1:1. The bionomics of moths surviving in the sprayed plots were different in several respects from those taken from unsprayed plots. The former emerged from pupae later, had lower levels of fecundity and a longer pre‐oviposition period. Females from sprayed plots were also heavierthan males and their weight was positively correlated with fecundity, whereas neither of those traits were shown by unsprayed moths. A number of other bionomic traits were not significantly different in sprayed or unsprayed groups. Analysis of the population growth rates of P. flammea from areas of the forest where control was eith...

The effect of temperature on oviposition, fecundity and egg hatch in the pine beauty moth, Panolis flammea (Lepidoptera: Noctuidae)

AbstractOver the temperature range 5° to 25°C, fecundity of Panolis flammea (Denis & Schiffermüller) showed a non-linear response, the optimal temperature for fecundity being 15°C. At 6°C females laid 17 eggs each whilst at 15°C they laid 166 eggs. Pre-oviposition period showed a significantly negative response, being shortest at 25°C (2.5 days). Adult longevity was significantly affected by temperature, being 20 days at 8°C and 6.8 days at 25°C. Egg hatch and development in the laboratory was linearly and positively related to temperature over the range of 2° to 20°C, ranging from 39.9 days at 5°C to 6 days at 25°C. The lethal limit for egg viability was 25°C. The theoretical threshold for egg development was calculated to be 2.79°C. Storage of eggs at temperatures of 2°C for periods in excess of 10 days had a significant effect on the percentage of eggs hatching. The significance of these findings in implementing control operations is discussed.

Influence of site factor modification on the population development of the pine beauty moth ( Panolis flammea) in a Scottish lodgepole pine ( Pinus contorta) plantation

This study tested an hypothesis that plant stress was a causative factor of Panolis flammea outbreaks on lodgepole pine ( Pinus contorta) in Scotland. Twenty-four, 1 ha plots of lodgepole pine were established on deep peat and ironpan sites. Six of these, three on each soil type, were left as controls. The remaining plots, also divided equally between the two soil types, were treated by: (1) fertiliser application; (2) thinning; (3) both. Populations of Panolis flammea were monitored from 1983–1988 over six generations. Populations peaked in 1984 and then declined. Populations in deep peat areas tended to be higher than in ironpan areas, although differences were small. Treatment effects were also small although some differences were found. Fecundity of adults was greater on deep peat sites. Compared with control plots, early larval mortality (egg-third instar) was greatest on ironpan sites, but also significantly greater in thinned sites. Mid-larval mortality (III–IV instar) was greater on deep peat sites but only in some years. Late larval mortality (IV instar-pupae) was greater on deep peat sites, and significantly greater on fertilised trees, but significantly reduced in thinned sites. Overwintering mortality was not affected by soil type alone, only by year, treatment and soil type interactions, which tended to be greatest in ironpan sites. Adult fecundity was the most important key factor on both soil types and in all treatments. Early larval mortality and late larval mortality were next most important factors on ironpan and deep peat sites respectively. The data provided no evidence to suggest than plant stress was a causative factor of Panolis flammea outbreaks on lodgepole pine in Scotland.

Activation and Detection of a Latent Baculovirus Resembling Mamestra brassicae Nuclear Polyhedrosis Virus in M. brassicae Insects

A laboratory culture of Mamestra brassicae insects (MbLC) has been found to harbor a latent baculovirus infection. The latent virus was activated by feeding the M. brassicae larvae with either the closely related Panolis flammea nuclear polyhedrosis virus (NPV), or the distantly related Autographa californica NPV. Restriction fragment profiles of the activated virus DNA showed that it is very closely related, if not identical, to M. brassicae NPV. Polymerase chain reaction amplification of polyhedrin gene sequences demonstrated that the latent virus was present throughout the life cycle of the insect; eggs, larvae, pupae, and adults. We failed to detect the presence of a latent virus in a second culture of M. brassicae insects, obtained from the environment and only recently adapted to growth in laboratory conditions, and thus these insects acted as an effective negative control in all the PCR and activation experiments. Using PCR analysis of DNA isolated from dissected tissues of fourth instar MbLC larvae, latent virus sequences were only detected in the fat body. Cell lines established from the isolated MbLC fat body tissue were also shown to harbor the latent virus sequences and should prove useful in further studies to elucidate the mechanisms of latency and virus activation.

Avian Dispersal of Nuclear Polyhedrosis Viruses after Induced Epizootics in the Pine Beauty Moth, Panolis flammea (Lepidoptera: Noctuidae)

Birds were trapped in three forest sites in Scotland after nuclear polyhedrosis virus (NPV) from the pine beauty moth, Panolis flammea, or cabbage moth, Mamestra brassicae, had been applied to control P. flammea populations. Collections were made late in the larval period when NPV infection was apparent in the field. In one site birds were also sampled when the P. flammea larvae were in the early instars and after the larvae had pupated. Bioassay of droppings collected from the captured birds showed that 9 of the 15 species trapped at NPV-treated sites had fed on virus-contaminated material. The proportion of NPV-positive birds collected late in the larval period ranged from 11.3%, in a trapping site near where small areas of forest had been treated, to 77.1% and 63.5% in sites where much larger areas had been sprayed. Samples collected early in the larval period yielded no virus, whereas 27.5% of the birds caught after the larvae had pupated were NPV positive. Estimates of the quantity of virus excreted by the birds ranged from 6 × 103 to 2.5 × 106 NPV polyhedra/mg of dropping and from 5 × 104 to 5.3 × 107 polyhedra/dropping. Restriction endonuclease analysis of NPV DNA from the samples confirmed their identity and demonstrated that most birds had ingested both P.flammea and M. brassicae NPV.

Sub-lethal plant defences: the paradox remains.

Lodgepole pine (Pinus contorta) trees of two different seed origins, one a poor quality host (Alaskan lodgepole pine), the other a good quality host (south coastal lodgepole pine), were infested with known numbers of eggs of the pine beauty moth, Panolis flammea. Each tree had paired sleeves, one allowing access by invertebrate predators, the other denying this access. When the sleeves were removed, the numbers of larvae surviving, their weights and developmental stages were assessed. Larvae reared on south coastal lodgepole pine (SLP) in the absence of predators were significantly heavier and had significantly better survival rates than larvae reared in comparable conditions on Alaskan lodgepole pine (ALP). However, in the open sleeves, although the larvae reared on SLP were significantly heavier than those on ALP, survival was significantly greater on ALP. Thus predation was greater on the faster developing larvae on the better quality host. These results indicate that slow growth by a herbivore does not necessarily result in greater vulnerability to predators.

The Influence of Soil Type and Pine Species on the Carabid Community of a Plantation Forest with a History of Pine Beauty Moth Infestation

The community composition of Carabid beetles, some species of which are known predators of pine beauty moth, was examined within a Scottish plantation forest. Sites differing in soil type and the species of trees planted were sampled with pitfall traps in most weeks of a 3-year period. There were faunal differences between sites with lodgepole pine on deep peat and other sites in the study (lodgepole pine on iron-pan soil, species mixture of lodgepole and Scots pine, and pure stands of Scots pine). In general deep peat sites supported fewer species and individuals of carabids. Three Carabus species were implicated as likely predators of Panolis flammea pupae and each was less abundant on the sites with lodgepole pine. It is suggested that the susceptibility to pine beauty moth of lodgepole pine growing on deep peat substrates is at least partly attributable to impoverished predator faunas.

Characterization of two variants of Panolis flammea multiple nucleocapsid nuclear polyhedrosis virus.

The baculovirus Panolis flammea multiple nucleocapsid nuclear polyhedrosis virus (PfMNPV) was originally isolated from a natural virus epizootic and shown to consist of a mixture of variants. Two subclasses of variants (PfMNPV A and B) were identified by Southern blot hybridization, their polyhedrin genes being located on different restriction fragments. The proportion of the A and B variants changed according to the larval host in which the virus was propagated; PfMNPV(B) predominated in P. flammea but PfMNPV(A) was predominant in Mamestra brassicae. Bioassays of the two pure virus variants in M. brassicae larvae have shown the LD50 values to be 4610 polyhedron inclusion bodies (pibs) for PfMNPV(A) and 5937 pibs for PfMNPV(B). Genomic DNA from the two variants was compared using restriction endonuclease analysis, and dot blot and Southern blot hybridization. Reciprocal quantitative dot blot hybridization analysis in 50% formamide showed PfMNPV(A) and PfMNPV(B) to be only distantly related to Autographa californica MNPV (less than 1%) and more closely related to M. brassicae MNPV (21 to 26%). The two PfMNPV variants exhibited a very high degree of identity to each other (nearly 100%) and therefore are very closely related. This was confirmed by physical mapping of the virus genomes. The nucleotide sequence of the polyhedrin gene of PfMNPV(B) was determined and compared with the published DNA sequences of other polyhedrin genes.

The influence of crown feeding position on the growth and survival of pine beauty moth larvae (Panolis flammea Den. & Schiff.) (Lep., Noctuidae)

AbstractThe growth, survival and rate of development of pine beauty moth (Panolis flammea) larvae on lodgepole pine (Pinus contorta) was studied at different crown heights on branches with contrasting aspects (north and south facing), and on branches with and without immature male flowers. Only crown height was found to affect larval performance. On average, over a 3‐year period, survival was 11% less, larval weight 50% lower, and larval development 51% slower among larvae feeding on lower crown branches in comparison to those feeding at the top of the crown.ZusammenfassungZum Einfluß des Fraßortes auf Wachstum und Überlebensrate der Kieferneulenraupe (Panolis flammea Den. & Schiff.) (Lep., Noctuidae)Die Wachstums‐ und Überlebensrate sowie die Entwicklung der Kieferneule (Panolis flammea) wurde an Pinus contorta in verschiedenen Kronenbereichen, an süd‐ und nordexponierten Ästen sowie an Ästen mit bzw. ohne männliche Blüten untersucht. Es konnte nur in Abhängigkeit von der Kronenhöhe ein Einfluß auf die Larvenentwicklung nachgewiesen werden. Im Durchschnitt konnte aufgrund der Ergebnisse einer dreijährigen Beobachtung gezeigt werden, daß im unteren Kronenbereich die Überlebensrate um 11% geringer, das Larvengewicht um 50% niedriger und die Larvenentwicklung um 51% langsamer waren als im oberen Kronenbereich.

The influence of pine shoot phenology on the survival of pine beauty moth ( Panolis flammea) larvae on different pine provenances

The survival of pine beauty moth, Panolis flammea, larvae was studied on 3 lodgepole pine, Pinus contorta, provenances and one Scots pine, Pinus sylvestris, provenance using plants at different stages of shoot elongation in 1986 and 1987. Larval survival was strongly influenced by pine shoot stage in both years: survival increased in late April and May, and declined in June. Differences in the pattern of larval survival in 1986 and 1987 were associated with differences in patterns of growth rates of pine shoots between the two years. Larval survival was much less affected by provenance; twice in 1986 larval survival was significantly different on different provenances, but on ten other occasions in 1986 and 1987 survival was not significantly different.

Ultraviolet penetration of pine trees and insect virus survival

Solar UV light entering Lodgepole pine,Pinus contorta (Loud.) canopy was measured by radiometer and polysulphone film. It was found to be much attenuated among lower branches and nuclear polyhedrosis virus exposed there was significantly more infective to Pine beauty moth,Panolis flammea (D.+S.) than virus from upper branches.

The effect of previous defoliation of pole-stage lodgepole pine on plant chemistry, and on the growth and survival of pine beauty moth (Panolis flammea) larvae.

A study of the effects of defoliation by insects on the chemistry of lodgepole pine (Pinus contorta), and on the performance of Panolis flammea (Lepidoptera; Noctuidae) larvae, was carried out in a forest in northwest Scotland I year after a severe outbreak of P. flammea had caused extensive defoliation. Larval weight and survival were not significantly different on trees that had experienced different levels of defoliation in 1986. The nitrogen and tannin content of current and previous years' pine needles was not significantly affected by defoliation (although both were slightly greater in the foliage of defoliated trees). Phosphorus content of young pine foliage was lower (but not significantly lower except on one occasion) on heavily defoliated trees. On all sampling occasions, however, the nitrogen: phosphorus ratio was significantly higher on heavily defoliated trees. There were large differences in monoterpene composition of the previous year's shoots associated with defoliation intensity, but these differences had largely disappeared in the new growth. The results are discussed in relation to other studies on the effects of insect damage on plant chemistry and insect performance and in relation to the abundance of P. flammea in Scotland.

Development of an integrated approach to control of pine beauty moth in Scotland

The pine beauty moth, Panolis flammea (D.&S.), is native to Great Britain. Prior to 1973 it was only known to occur at endemic levels on Scots pine, Pinus sylvestris L. In the mid-1970s, outbreaks of the moth were discovered in plantations of the exotic lodgepole pine, Pinus contorta Loud., in Scotland. Two phases of research and management activity have culminated in an integrated pest-management system. The first phase, from 1976 to 1981, involved development of survey methods, establishment of population and damage thresholds, introduction of ultra-low-volume aerial application of fenitrothion, and basic work on the ecology of P. flammea. The second phase, from 1982 to 1988, has included refinement of control methods through the development and use of alternative active ingredients, including diflubenzuron (Dimilin ®) and nuclear polyhedrosis virus (PfNPV), and improvement of application equipment and techniques. Concurrent research into the ecology and population dynamics of P. flammea has indicated the importance of site, especially peat soils, in determining pupal survival. Most outbreaks have been associated with deep peat sites. Oviposition and larval development have been related to suitability of tree species and seed origins, the cues for the former being provided by monoterpenes, particularly the ratios of β-pinene to α-pinene in the host plants. These data are being brought together in developing an integrated pest-management approach for this pest.

The toxicity of deltamethrin to pine beauty moth Panolis flammea schiff. and its parasitoids Barichneumon bilunulatus grav. and Rictichneumon pachymerus katz

AbstractThe toxicity of deltamethrin to larvae of the pine beauty moth, Panolis flammea Schiff., and its two parasitoid species, Barichneumon bilunulatus Grav. and Rictichneumon pachymerus Katz., was evaluated. Two methods, exposure of insects on treated filter paper and topical application of insecticide, were used. Results showed that larvae of the pest were many times more susceptible to deltamethrin than imagines of either of the two parasitoid species.

Outbreaks of the pine beauty moth on pine in Scotland: Influence of host plant species and site factors

In Scotland, outbreaks of the pine beauty moth ( Panolis flammea Denis and Schiffermuller (Lepidoptera, Noctuidae)), do not occur on its native host, Scots pine ( Pinus sylvestris L.), but are associated with lodgepole pine ( P. contorta Douglas) growing in deep unflushed peat. A number of different approaches have been adopted to test the hypothesis that pine-beauty-moth outbreaks are caused by an increase in the nutritive quality of the foliage of the host plant due in some way to the ‘stress’ imposed by being grown in deep peat relative to the quality of trees growing more vigorously in better soils. These approaches were: the monitoring of natural and manipulated populations; studies of the growth and survival of larval cohorts from which predators were excluded; analysis of the chemical content of pine foliage; the manipulation of plant quality by thinning and fertilizer application; and subsequent observations of foliar chemistry and population development. No evidence was found to support the ‘stress’ hypothesis; neither was any evidence found to support the view that Scots pine is a poorer host plant than lodgepole pine. Alternative hypotheses are discussed, and it is concluded that predation and parasitism may be responsible for the observed outbreak behaviour of pine-beauty-moth populations in Scotland.

Life span and ovarian dynamics of the pine beauty moth, Panolis flammea (D&S): the effect of low temperatures after adult emergence on reproductive success

Abstract Adult female Panolis flammea were kept at 2oC either immediately after emergence from the pupae or immediately after mating, for periods ranging from 5 to 20 days and then placed at 15oC together with a male moth, food supply and suitable oviposition site (Pinus contorta foliage). Weight loss over the storage period was directly proportional to the time spent at 2oC irrespective of whether the moths were virgin or mated. Pre‐oviposition period decreased significantly from the control after more than 5 days at 2oC, but there was no significant difference between late mated and early mated moths. The post‐storage life span of late mated and early mated moths decreased in proportion to the time spent at 2oC but late mated moths had significantly longer life spans than early mated moths. Moths mated prior to storage were significantly less fecund than moths mated after storage except those moths kept at 2oC for 20 days where the fecundities of both treatments were identical (c. 45 eggs/female). These results are discussed in relation to the conditions likely to be experienced by P.flammea in the field and their bearing on the population dynamics of this insect.

Heavy-Metal Contents in Pupae of Bupalus piniarius (Lepidoptera: Geometridae) and Panolis flammea (Lepidoptera: Noctuidae) near an Industrial Source

The concentrations of copper (Cu), iron (Fe), nickel (Ni), and cadmium (Cd) were analyzed in the pupae of Bupalus piniarius (L.) and Panolis flammea (Denis and Schiffermuller) reared on needles collected from the same sites with different heavy-metal levels. Metal analysis on an individual basis revealed specific differences between the two common defoliators of the Scots pine ( Pinus sylvestris L.). The highest heavy-metal concentrations in B. piniarius (Cu 137, Fe 83, Ni 2.1, Cd 0.9 μgg−1)and P. flammea (Cu 89, Fe 59, Ni 5.3, Cd 2.9 μgg−1)were recorded in those reared on needles from the vicinity of the emission source in Finland. The decreasing trend of the log-transformed metal concentrations followed a linear regression model with increasing distance from the factories. The ratio between the concentration of copper and iron in the insects and that in the needles was proportionally lower in heavily polluted areas. Cadmium bioaccumulation was observed in P. flammea but not in B. piniarius .

Influence of droplet size, solar ultraviolet light and protectants, and other factors on the efficacy of baculovirus sprays against Panolis flammea (Schiff.) (Lepidoptera: Noctuidae)

Protectants aimed at reducing the effect of solar ultraviolet light were formulated with nuclear polyhedrosis virus sprays used against pine beauty moth ( Panolis flammea (Schiff.)) in Scottish forests and evaluated in a field trial and by a bioassay. Trees c. 2 m high were sprayed at ultra-low volume using two droplet sizes, on two occasions. Test formulations included virus with egg albumen on its own or with Tinopal, lignosulphonate or riboflavin, and virus with an emulsified mineral oil, Actipron. Ultraviolet light was measured by radiometer and polysulphone film. Larvae were monitored day-to-day in the bioassay and after gathering field samples, until most infected larvae had died. Infection levels were significantly affected by spray droplet size, and exposure before ingestion. Small droplet sprays led to higher infection levels than large droplet sprays. Infectivity declined on exposure to weather. Infection levels on the larger trees were lower than on small ones. The different formulations performed in a similar way, whether exposed or not; the three protectants added to the spray conferred no obvious benefit at the concentrations used.

The effect of time of spray application on infection of the pine beauty moth, Panolis flammea (Den. & Schiff.) (Lep., Noctuidae), with nuclear polyhedrosis virus

AbstractPanolis flammea nuclear polyhedrosis virus was applied to pine beauty moth, P. flammea, infesting lodgepole pine (Pinus contorta), on six separate occasions. The plots were monitored for seven weeks after hatch using destructive sampling to obtain an estimate of infection and population age structure. Highest levels of infection were obtained in the plot sprayed 6 days after 95% hatch, when over 70% of the sprayed population were first instar larvae. Spraying earlier than this resulted in lower levels of infection: spraying after this resulted in similar or slightly decreased infection. Investigation of the instars infected showed that the earlier sprays, when the P. flammea population was solely or predominantly in the first instar, resulted in a peak of infected larvae in the third instar. Later sprays, when the population was mainly second instar larvae, resulted in an infection peak in fourth instar larvae. The implications for P. flammea control are discussed.ZusammenfassungEinfluß des Zeitpunkts der Spritzung auf die Infektion von Panolis flammea (Den. & Schiff.) (Lep., Noctuidae) mit KernpolyedervirusPanolis flammea NPV wurde in sechs getrennten Versuchen gegen die Forleule, P. flammea, in Kiefernbeständen (Pinus contorta) eingesetzt. In diesen Gebieten wurden nach Schlüpfbeginn der Raupen noch sieben Wochen lang Proben entnommen, um Einblick in Infektion und Altersstruktur der Population zu erhalten. Die höchste Infektionsrate wurde in dem Gebiet festgestellt, das 6 Tage nachdem 95% der Raupen geschlüpft waren, gespritzt wurde, so daß zum Zeitpunkt der Behandlung 70% der Population in L1 war. Die Spritzung zu einem früheren Zeitpunkt ergab niedrigere Infektionsraten; wurde hingegen zu einem späteren Zeitpunkt gespritzt, ergaben sich vergleichbare Infektionsraten. Die Untersuchung der infizierten Larvenstadien zeigte, daß Spritzungen zu einem frühen Zeitpunkt, zu dem die P. flammea Population ausschließlich oder überwiegend in L1 war, eine maximale Infektionshäufigkeit in L3 ergab. Spätere Spritzungen, wenn die Population hauptsächlich aus Larven in L2 bestand, bewirkten die höchste Infektionshäufigkeit in L4. Die Bedeutung dieser Ergebnisse für die Schädlingsbekämpfung wird erörtert.

Interactions between pheromone traps with different strength lures for the pine beauty moth,Panolis flammea (Lepidoptera: Noctuidae)

Catches of malePanolis flammea in traps baited with lures containing 25 μg of sex attractant are enhanced when in the proximity of traps baited with 125-μg lures. The degree of enhancement is increased as the intertrap distance is decreased, and when the low-dose trap is upwind of the high-dose one. The patterns of alteration in trap catch suggest that moths initially attracted by one lure may divert into other traps, which may be either upwind of the original trap ("overshooting"), or downwind ("undershooting"). "Overshooting" can result in up to fivefold increases in catch and may provide a useful method for estimating the attractant zone of particular lure/trap combinations.