Spruce budworm

Western spruce budworm, Christoneura occidentalis, sixth instar stage Arsenic trioxide pestiferous species Dietary levels of 99.5 mg/kg FW killed 10%, 2250 mg/kg 7... 

Lechowlcz, M.j In "Proceedings, Forest Defoliator--Hos t Interactions A Comparison Between Gypsy Moth and Spruce Budworms" General Technical Report NE-8 5, USDA Forest Service Washington, DC, 1983 pp. 67-86. 

Patterns in Defensive Natural Product Chemistry Douglas Fir and Western Spruce Budworm Interactions... 

Our objective Is to examine some aspects of current plant herbivore theory using Douglas-flr (Pseudotsuga menzlesll) and western spruce budworm (Chorlstoneura occldentalls). Both plant and herbivore are widespread In western North America. Natural hosts of the budworm Include Douglas-flr, species of Abies, and, on occasion, other conifers (9). Variation In budworm density occurs on both a geographic and local scale. We have frequently observed differential defoliation In trees having overlapping crowns at sites In Montana, Idaho, and New Mexico. 

Our focus was upon natural and experimental studies that were designed to Investigate various aspects of the current plant-herblvore theory using the Douglas-flr/western spruce budworm system. Specifically, we wished to test whether there are chemical characteristics In the young needle tissue of Douglas-flr that reduce the growth, survival, and adult fecundity of the western spruce budworm. Secondly, we were Interested In... 

Redak, R. "A Determination of the Resistance-Susceptibility Characteristics In Douglas-flr to the Western Spruce Budworm" MS Thesis, Unlv. of New Mexico, Albuquerque, NM, 1982, pp 1-74. 

Phenological Synchronization. Induced delays in budbreak in balsam fir reduce feeding by the spruce budworm, and defoliation and desquaring in cotton depress overwintering success of several major cotton pests. Table IV presents a summary of the work on these two systems. 

Balsam F ir Abscisic Acid Maleic Hydrazide Chlorf lurenol Spruce Budworm Delayed budbreak 1325... 

When abscisic acid is applied to balsam fir, the break of buds in the spring is delayed and the emerging spruce budworm, Choristoneura fumiferana, larvae are forced to feed on old needles, which are a less desirable food. Attempts have been made, rather unsuccessfully, under natural forest situations, to manipulate budbreak with growth retardants for the control of the spruce budworm. However, this system seems to operate under controlled greenhouse conditions, and with some adjustments, it may have potential for practical applications in the field (32). 

An entirely different, in fact opposite, effect on insect reproduction by terpenes occurs with the desert locust. In this case the monoterpenes a-pinene, -pinene, llmonene, and euge-nol evaporating from desert shrubs about to bloom, precipitates synchronised sexual maturation and mating activity in the locusts (14). The spruce budworm is also stimulated to increased fertility levels by host tree monoterpenes (R.G. Cates, personal communication). It is possible that even opposite effects on reproduction in insects could occur depending on the specialisation of the insect species to its environment, the diversity of the biological activities of the compounds, and the high level of complexity of the reproductive processes. 

The salts of fatty acids (not naturally occurring) have long been known to have insecticidal properties. The most effective potassium salts center around oleate in the monounsaturated and saturated series, although potassium caprate (Cio) was especially active against Choristoneura occidentalis (Western spruce budworm) and Acleris gloverana (Western blackheaded budworm) (117). 

Bentley, M. D., Leonard, D. E., Stoddard, W. F. and Zalkow, L. H. (1984). Pyrrolizidine alkaloids as larval feeding deterrents for spruce budworm, Choristoneura fumiferana (Lepidoptera Tortricidae). Annals of the Entomological Society of America 77 393-397. 

Delisle, J. and Hardy, M. (1997). Male larval nutrition influences the reproductive success of both sexes of the spruce budworm, Christoneura fumiferana (Lepidoptera Tortricidae). Functional Ecology 11 451 163. 

E)-l 1-tetradecenal [35746-21-5] CH3CH2CH=CH(CH2)9CHO eastern spruce budworm, Choristoneura fumifemna... 

The coddling moth (deciduous fruits) pink bollworm (cotton) the gypsy moth and spruce budworm, two defoliators of our forests. 

DDT, discovered by Dr. Mueller in Switzerland, and used for insect vector control during World War II, quickly found a place in forestry, as well as agriculture. The material proved highly effective in the control of such insects as the spruce budworm, tussock moth, hemlock looper, and many others. It was widely used in the Northeast for control of the introduced Gypsy moth during these early years. The low toxicity of DDT to mammals made it to appear to be an excellent insecticide for forestry use. It was only after subsequent studies revealed the impact on other species that reservations about its use was raised. 

The chemical and behavioral aspects of the sex pheromones of several forest defoliating insects of economic importance in eastern Canada are presented, with emphasis on the spruce budworm, Choristoneura fumiferana. Studies conducted over several years in New Brunswick on the use of pheromones as potential control agents, using in particular the air permeation technique to effect mating disruption, are discussed. The identification and the behavioral effects of minor components of the spruce budworm pheromone system are presented and the potential exploitation of their behavioral roles in the mating sequence in terms of control strategies are addressed. 

This paper will review the uses of pheromones for detection, monitoring and possible control of eastern forest Lepidoptera. As an illustrative example, particular reference will be made to the control of the spruce budworm, the techniques used and the problems involved including limitations due to economics and lack of biological information on this species. 

As in most Lepidoptera, spruce budworm males locate conspecific females by flying upwind along a pheromone plume. The blends and release rates of these pheromone components form an important part of a specific communication system for the species. Once the communication system of an insect is understood, especially the pheromone chemistry as it relates to male behavior, it can be used in a variety of ways. For example, pheromones can be used to detect the presence of an insect in an area, to remove males from a population by trapping or poisoning and in air-permeation techniques in which the controlled and continuous release of pheromone components in the forest can disrupt mating. The latter use of pheromones appears to alter the normal male behavioral responses to the natural pheromone (16). 

Review of Spruce Budworm Pheromone-mediated Behavior... 

It is apparent that not all the chemicals involved in female-to-male communication in the spruce budworm are known. In monitoring and mating disruption programs, however, it may not be essential to know every minor component, although as Roelofs has pointed out (16), trap specificity and potency may be greatly increased as the synthetic lure more closely duplicates the natural pheromone and it is presumed that the efficacy of mating disruption would likewise be enhanced by the "more complete pheromone". 

Present methods for the detection and population survey of spruce budworm rely on the sampling of egg masses on tree foliage. Pheromone traps could probably detect moths at lower densities than the present method and this information could be used to prevent or decrease the development of an epidemic infestation of spruce budworm. However, a great deal of work is still required to correlate trap capture with moth population densities and with damage to trees. 

The spruce budworm is considered a "high density" pest since it occurs at damaging densities of > 1CT adults per hectare. In epidemic situations it occurs in densities sometimes orders of magnitude higher. Under such conditions, it is questionable that pheromone alone could suppress populations. However, recent work has shown some disruptive effects on reproductive behavior even at these high densities and... 

Mating disruption experiments with spruce budworm in laboratory, small-scale field tests and "semi-operational" field trials have recently been reviewed (27). Work to date, on the disruption of spruce budworm mating behavior has concentrated on the use of the primary components /Zll-14 Ald s (95-97% E), and the results indicate that some mating disruption does occur. There appears to be a positive correlation between the applied pheromone concentration and the percent disruption, and based on field cage studies, percent disruption is inversely related to insect density (27) as would be predicted (32). 

Previous tests of the aerial application of synthetic sex attractant of the spruce budworm resulted in reductions of up to 90% of males captured in traps baited with virgin females and/or synthetic pheromone. However, there has been no convincing demonstration of reduction in population density in the subsequent generation (33). 

Pheromone releaser distributions and/or point-source release rates have pronounced effects on the disruption of trap captures of spruce budworm (39). Small field plot studies with hand-placed releasers in moderate- to-high density budworm populations indicate an increase in trap disruption as the point sources of the synthetic pheromone are increased in release rate and decreased in number per unit area (Fig. 1). Identical pheromone dosages per plot were present in each treatment. Optimizing the releaser spacing and point-source release rate is therefore important and implies the need for a formulation re-design. This effect of releaser distribution and point-source release rate on trap disruption and mating disruption has been demonstrated in several insect species (40). 

Miller, C. A. Report of Spruce Budworm Pheromone Trials, Maritimes, 1978. Pep. Environ. CFS, Fredericton. File Report 1980. 

Figure 1. Comparison of average number of western spruce budworm egg masses in treated and untreated areas,...

---