Forest Pest Control Research Articles

Molecular modifications of Baculoviruses for the control of forest insect pests

Publisher Summary This chapter describes some of the more recent research in the areas of gene cloning and recombinant viruses, genome sequencing of spruce budworm viruses, and development of cell lines. The insect communities in the forests often contain a rich complex of natural enemies of the insects, such as parasites, predators, bacteria, fungi, and viruses. These natural enemies can be used as control agents and are attractive alternatives to chemical pesticides, because they are not only naturally occurring but also in many instances host specific with little or no adverse effects on the environment. Many insect viruses are attractive as environmentally benign control agents, because their host range is generally quite narrow, infecting only a few species or genera. This narrow host range permits the use of insect viruses in integrated pest management of forests. Although the viruses eventually kill the insects, because they take a long time to act, the pest insect often causes extensive defoliation before they die. The forest ecosystem is an environmentally sensitive region and is, especially suited for the use of environmentally safe baculoviruses as control agents. Recombinant DNA technology has provided a powerful tool to genetically manipulate the viruses and make it possible to enhance the control potential of baculoviruses.

Sensitivity of amphibian embryos and tadpoles to Mimic® 240 LV insecticide following single or double exposures

AbstractMimic® 240 LV is a novel, narrow‐spectrum insecticide containing the active ingredient tebufenozide. Tebufenozide mimics the action of the insect molting hormone ecdysone and shows specific activity toward larval Lepidoptera. In Canada, Mimic 240 LV has been proposed for use in forest pest control, whereas a different formulation has been registered for use in agriculture. We examined the effects of single and double pulses of Mimic 240 LV (tebufenozide) on the development, growth, and predator avoidance behavior of four frog species (wood frogs Rana sylvatica, leopard frogs R. pipiens, green frogs R. clamitans, and bullfrogs R. catesbeiana) exposed in the laboratory as embryos or tadpoles. Nominal doses ranged from 3.0 mg/L to 9.0 mg/L tebufenozide, and exposures were terminated at 96 h following single, or 192 h following double, exposures. More than 90% of the animals exposed as embryos hatched. Embryos exposed late in development and subsequently hatching into tebufenozide‐contaminated water all hatched and responded normally. Tadpole growth was not delayed following exposure, and premetamorphic green frogs successfully completed metamorphosis following exposure to the highest concentration. The results suggest that Mimic 240 LV, when used at the suggested application rates, will not severely affect the aquatic stages of ranid amphibians.

Gypchek: Biological Insecticide for the Gypsy Moth

Abstract Responding to concerns over the use of chemical pesticides, the USDA Forest Service has developed narrow host-range products for the control of forest pests. Among them is Gypchek, a viral Pesticide for gypsy moths, but its future availability is not assured. If the private sector will not produce a safe and useful pesticide because the market is unstable, some other approach toward developing such products and making them available is needed. A federal center may be necessary to research biopesticides, transfer technology to the private sector, and develop, register, produce, and market those products that industry will not.

FOLIAR AND SYSTEMIC APPLICATIONS OF NEEM SEED EXTRACT FOR CONTROL OF SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (CLEM.) (LEPIDOPTERA: TORTRICIDAE), INFESTING BLACK AND WHITE SPRUCE SEED ORCHARDS

AbstractNeem seed extract (20, 60, and 180 ppm azadirachtin) applied to the crowns of black spruce trees immediately prior to female reproductive bud flush, resulted in high mortality of early instar spruce budworm larvae. Dose-dependent reductions of 40–93%, as compared with check trees, were observed 2 and 4.5 weeks after treatment. Seed cone protection from grazing damage, however, was moderate; at 60 ppm azadirachtin, the incidence of cone grazing was reduced 29%, and the proportion of severely grazed cones reduced 39%, as compared with check trees. Larval mortality and bud damage observed in the laboratory corroborated field results. High toxicity to second-instar larvae, and performance during adverse weather conditions, supports the potential of neem seed extract for control of spruce budworm defoliation. However, both laboratory and field results indicate that feeding occurs before the effects of neem seed extract manifest, resulting in moderate protection of cones. Whereas foliage can tolerate low levels of feeding, female strobili are damaged significantly. Excellent protection of foliage was achieved from systemic injections of neem seed extract to white and black spruce trees (1.5 g azadirachtin/tree). Neem seed extract, formulated for systemic application, could provide a botanical alternative for control of forest pests in urban environments.

A Bug Is a Bug Is a Bug: Symbolic Responses to Contingent Valuation Questions about Forest Pest control programs?

Symbolic responses are one of many issues attending contingent valuation studies. The problem is that many objects that are the subject of contingent valuation surveys can act as symbols for larger issues. In this paper, we want to compare the attitudes of residents of five communities with two different forest pests, jack pine budworm and gypsy moth. Jack pine budworm affects commercially important forests in Canada, while gypsy moth generally affects recreational areas and has less commercial significance. All of the respondents were asked about both insects; however, not all of the communities had direct experience with both insects. The purpose is to examine whether respondents would differentiate their willingness to pay for control mechanisms between these different defoliators. The implication is that all bugs are alike and generally noxious, a notion that would not necessarily sit well with resource managers who have to deal with insect outbreaks. Respondents did not differentiate strongly between insect control programs that would impact their community and those that would not. While not conclusive, the results do suggest symbolic responses to this particular issue. This is further evidence that willingness‐to‐pay results from contingent valuation studies need to be cautiously interpreted as pseudo market values.

Nontarget Effects of Neem-Based Insecticides on Aquatic Invertebrates

Neem-based insecticides are being investigated as alternatives to synthetic insecticides for the control of forest insect pests in Canada. Because the proposed use pattern against forest defoliators often necessitates spraying near shoreline areas, an assessment of adverse effects of neem on nontarget aquatic invertebrates was warranted. Acute lethal effects of two neem-based formulations on eight species of macroinvertebrates were determined in flow-through screening tests at 10 times the expected environmental concentration (0.35 mg/liter). Significant mortality occurred only in the mayflyIsonychia bicolor/rufaexposed to one formulation, and further tests were conducted to determine a concentration-dependent response. The LC50forI. bicolor/rufawas estimated at 1.12 mg/liter; the LC10was 0.63 mg/liter. Three detritivorous species were tested at expected environmental concentrations (0.035 mg/liter) at longer exposures in aquatic microcosms to determine effects of the two formulations on feeding rates and survival. Neither formulation caused significant mortality or antifeedant effects after a 28-day exposure. The implications of these results for forest pest management operations are discussed.

Biotechnology in forestry: Examples from the Canadian Forest Service

As a general trend, research activities related to biotechnology in the Canadian Forest Service (CFS) have increased significantly during the last decade as illustrated by a marked increase in resources committed to this field and in the number of publications produced by the scientists involved. The three areas covered by CFS biotechnological activities are forest regeneration, forest protection and environmental impact assessment. In forest regeneration, the tissue culture of conifers using somatic embryogenesis is a good example of potential application of biotechnology to conventional tree improvement. This technology is being used on a large scale in British Columbia and involves private firms such as BC Research Inc. Other technologies are also being developed such as genetic engineering which eventually will allow the incorporation of advantageous traits into trees which would otherwise be difficult or impossible to achieve. In forest protection, Bacillus thuringiensis is a well known success of biotechnology. This bacterium is used as a biopesticide in Canada to control spruce budworm and gypsy moth. Its use has been increasing during the last few decades and, with the phasing out of chemical insecticides for forestry use, Bacillus thuringiensis will become one of the few alternatives available for insect control. Insect viruses are also becoming more attractive for the biological control of forest pests. The CFS has registered three viruses for forestry use and the next generation of viruses will be genetically engineered to increase their efficiency and effectiveness. The last area of activity encompasses environmental impact studies of biotechnology products for forestry use. The CFS has been a pioneer in the development of microcosms (soil and aquatic) for studying microbial pesticides used to evaluate the impact of engineered biopesticides. Key words: biotechnology, genetic engineering, biopesticides, molecular biology, tissue culture, microcosm, regulation, environmental impact

Integrated pest management in forestry: some difficulties in pursuing the holy-grail

Summary As Australian forests become more intensively managed, there is increasing interest in the development of integrated pest management (IPM) strategies for the control of forest pests. IPM, in the strict sense, is a research model which uses tools such as economic injury levels (EIL's), growth impact models and pest population monitoring to help coordinate the application and timing of pest control techniques. Because of economic and practical constraints (such as effective monitoring, determination of EIL's and low operating budgets), I argue that IPM may be an inappropriate model upon which to base research priorities. As an alternative, I remind both researchers and forest managers that many pest control techniques, such as biological control and silvicultural management, can be used effectively outside an IPM framework. Because forest managers ultimately dictate the level of support which is given to forest health management, it should be at the corporate level, rather than the research level, that the decision as to which pest management model to be followed is made.

Microbial insecticides in forestry

Research has been conducted in Canada on bacteria, viruses, protozoa, fungi and nematodes for control of forest insect pests. Environmental concerns regarding the use of synthetic chemical pesticides have resulted in increased use of the only microbial control agent that is commercially available, the bacterium Bacillus thuringiensis (B.t.). There are currently 18 B.t. products registered for forestry use in Canada. The greatest use of B.t. has been for control of spruce budworm, Choristoneura Jumiferana, although it has been extensively used on several other species of defoliating lepidopterous pests.The use of other microbial control agents is insignificant compared to B.t. Three viral insecticides containing baculoviruses are registered in Canada, two for control of Douglas-fir tussock moth and one for control of redheaded pine sawfly. Registration petitions have been submitted for viral insecticides to control European pine sawfly and gypsy moth.The advent of recombinant DNA technology has opened the door to limitless possibilities for the genetic manipulation of microbial insecticides. Genetic engineering of B.t. toxin genes into other microorganisms and into plants has been accomplished. Foreign genes have been expressed in baculoviruses; most of these products have pharmaceutical applications unrelated to insect control, but this technology can be used to engineer viral insecticides for enhanced activity.

Social, economic and policy aspects of integrated pest management of forest defoliators in India

About half a dozen insects are important forest defoliators in India, and they are primarily pests of plantations. No progress has been made towards their integrated management, in spite of some good beginnings in the 1930s. Socio-economic factors have been the main hindrances to successful development and adoption of IPM strategies against forest defoliators. Virtually all forests in India are government-owned, and forest pest control has been accorded low priority relative to the more pressing agricultural pest problems. Added handicaps are the small number of forest entomologist, their inadequate training in the concepts and techniques of IPM, the lack of adequate recognition and rewards for applied research, and the absence of purposeful research management at institutional and national levels in forestry (which is being corrected with the establishment of an Indian Council of Forestry Research and Education). In retrospect, the past neglect of forest pest control in India has saved the forest ecosystem from the onslaught of chemical pesticides. The present trend in agriculture is away from chemicals to IPM, and state ownership of forests is conducive to the implementation of IPM. But IPM research and implementation have their own inherent difficulties. Massive training efforts are needed to bring about the needed shift in emphasis in research approaches. Equally important needs are adnministrative decisions to correct the inflexibility of institutional structures to meet the new demands of coordinated research much needed for the success of IPM in practice in spite of its wide acceptance as a concept.

Biological control of forest aphid pests in Africa

AbstractThe aphids, Cinara cupressi (Buckton), Eulachnus rileyi Williams and Pineus pini (Macquart), have invaded conifer plantations in southern and eastern Africa between 1968 and 1986. Conifer plantations, and particularly pine plantations, are a new habitat in this region, having been established in the 1960s and 1970s. These aphids are the first non-native pests to colonize these forest plantations. As exotic pests, the aphids are suitable targets for classical biological control through the importation of natural enemies from Europe, the region of origin of the three aphids. The opportunities for biological control are explored and the prospects are encouraging. Details of the natural enemy complexes of the target pests in Europe are provided and discussed in relation to previous successful biological control programmes against conifer pests in other continents.

The recent Canadian record in applied biological control of forest insect pests

The applied biological control of 21 forest insect pests was recently evaluated in Canada. One-third of these pests have been almost permanently controlled in their present environment. One-third of the pests can be controlled for one to several pest generations. The remaining third were either not controlled or the evaluation of the applied biological control has not been completed. Benefit:cost data are scant and those available are rudimentary. Ratios of at least 20:1 were calculated for two successes with long-term control. Higher ratios were obtained when the control economics were examined from the perspective of the forest manager. Only the production of Bacillus thuringiensis is sufficiently profitable for private industry to undertake supply. Applied biological control has a good record of environmental compatibility. Prospects for the control method are briefly outlined.

Improving Efficiency in a Forest Pest Control Spray Program

The Maine Forest Service limits the destruction of Maine spruce-fir forests by spruce budworms through a large aerial spray program. They use several types of aircraft flying from six airfields to spray 250 to 300 infested areas. A mathematical programming model which determines the lowest cost set of flight plans and provides “what if” analyses for changes in operating conditions is improving management decisions.

Predaceous Ants in Biological Control of Insect Pests of North American Forests

Ants are common and usually ignored members of forest communities, yet their activities affect forests in many ways. Their nesting in soil aids soil aeration, movement of soil particles to the surface, accumulation and breakdown of organic matter, and nutrient recycling (Petal 1978). Ants influence vegetation patterns by dispersing seed while foraging, and by creating favorable or unfavorable microhabitats for plant growth near ant mounds. Ant foraging, whether for plant or animal material, can affect both the population dynamics and the distribution of species commonly included in the ants' diet. Although ants feed on a wide range of organic material, my discussion is confined to those ant species that habitually prey on other insects—species that can play an important role in the biological control of forest insect pests.

World Forestry: Forest Research and its Prospects in the People's Republic of China

Abstract Long experience has provided China with much practical knowledge about her complex forest sites and ecology, but only recently has the nation begun systematic research on a substantial scale. Now she is making progress in forest surveys, silviculture, tree breeding, and pest control; and some basic research is under way in dendrology, soils, tree physiology, and biochemistry. Much remains to be done, and if progress is to be speeded it is desirable to keep the research institutions stable, increase the number of experimental forests, strengthen basic research, and promote scientific cooperation within the People's Republic and with other nations.

Pulpwood, pesticides, and people. Controlling spruce budworm in northeastern North America

The eastern spruce budworm is a major forest pest over the continental range of the spruce-fir forest ecosystem and its southern ecotonal fringes in Canada and the northeastern United States. The current budworm outbreak illustrates the difficulty of arriving at economically sound and publicly acceptable forest pest control policies. Policies ranging from no use of chemical control to annual widespread crop protection have been adopted. There is no single all-around “best” policy for spruce budworm control. Chemical spray programs have demonstrably slowed the normal progress of mortality due to budworm, but have not eradicated the pest. Where industry remains heavily dependent on a fully utilized spruce-fir forest, no easy, low-cost solutions to the budworm problem exist. Reliance on spraying will have to be reduced and plans made to utilize higher levels of tree mortality and to manage the forest for lower future vulnerability.

Estimating the Southern Pine Beetle's Hydrologic Impact

Decisions concerning institution or expansion of forest pest control programs should be based on all relevant effects of the pest. The southern pine beetle (Dendroctonus frontalis Zimm.) is a forest pest and the forest's watershed values could be affected by it (Leuschner and Newton 1974). This study's objectives were to develop a methodology for estimating the physical impacts of D. frontalis infestations on forest-produced water and to place a value on that impact within the benefit-cost framework.

Forest Pest Control: Volume IV of Pest Control: An Assessment of Present and Alternative Technologies

Forest Pest Control: Volume IV of Pest Control: An Assessment of Present and Alternative Technologies

Pest Control: An Assessment of Present and Alternative Technologies. Vol IV Forest Pest Control

Pest Control: An Assessment of Present and Alternative Technologies. Vol IV Forest Pest Control

Recent Development in ULV Techniques

SummaireSome interesting problems concerning the European and Mediterranean areas which can be solved by using ULV techniques are discussed. Malathion ULV Concentrate with and without protein bait is compared with conventional cover sprays to control Dacus oleae Gmel. and Ceratitis capitata Wied. Evidence is given demonstrating the advantages of ULV techniques for cotton and forest pest control. In field crops good results have been obtained against Meligethes spp., Athalia spp. and it appears that Eurygaster spp. can be effectively controlled by ULV fenitrothion sprays. Further tests are still required to determine more precisely the dosage required for the control of adults and the different larval instars of these species. The main concern of the Cyanamid work within the ULV treatment is in avoiding environmental pollution as far as possible.